1

The Art of Nanoscience for the

Conservation of Art

Luigi Dei

Department of Chemistry ldquoUgo Schiff rdquo

amp CSGI Consortium

University of Florence

2

TopTop--toto--bottom or bottombottom or bottom--toto--top totop to synthesizesynthesize nanostructurednanostructured hard and soft hard and soft mattermatter

3

4

CaCa(OH)(OH)22 nanoparticles with high degree of physicochemicalnanoparticles with high degree of physicochemical compatibility for consolidationprotection ofcompatibility for consolidationprotection of wall paintings and wall paintings and limestoneslimestones MicellarMicellar systems and watersystems and water--based based microemulsionsmicroemulsions -- green systemsgreen systems -- for cleaning architectonicartistic surfaces for cleaning architectonicartistic surfaces Polymeric systems waterPolymeric systems water--cosolventscosolvents with peculiar viscoelasticwith peculiar viscoelastic properties for selective and controlled cleaning of easel paintingsproperties for selective and controlled cleaning of easel paintings

5

Decay of painting layers from coherent porous material

to incoherent granular matter

Many factors among which the most important atmospheric pollution

determine the loss of adhesioncohesion properties originating

surface powdering

lifting and bowls of painting layers

surface opacification (light scattering)

NEED OF PRE-CONSOLIDATION

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

2

TopTop--toto--bottom or bottombottom or bottom--toto--top totop to synthesizesynthesize nanostructurednanostructured hard and soft hard and soft mattermatter

3

4

CaCa(OH)(OH)22 nanoparticles with high degree of physicochemicalnanoparticles with high degree of physicochemical compatibility for consolidationprotection ofcompatibility for consolidationprotection of wall paintings and wall paintings and limestoneslimestones MicellarMicellar systems and watersystems and water--based based microemulsionsmicroemulsions -- green systemsgreen systems -- for cleaning architectonicartistic surfaces for cleaning architectonicartistic surfaces Polymeric systems waterPolymeric systems water--cosolventscosolvents with peculiar viscoelasticwith peculiar viscoelastic properties for selective and controlled cleaning of easel paintingsproperties for selective and controlled cleaning of easel paintings

5

Decay of painting layers from coherent porous material

to incoherent granular matter

Many factors among which the most important atmospheric pollution

determine the loss of adhesioncohesion properties originating

surface powdering

lifting and bowls of painting layers

surface opacification (light scattering)

NEED OF PRE-CONSOLIDATION

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

3

4

CaCa(OH)(OH)22 nanoparticles with high degree of physicochemicalnanoparticles with high degree of physicochemical compatibility for consolidationprotection ofcompatibility for consolidationprotection of wall paintings and wall paintings and limestoneslimestones MicellarMicellar systems and watersystems and water--based based microemulsionsmicroemulsions -- green systemsgreen systems -- for cleaning architectonicartistic surfaces for cleaning architectonicartistic surfaces Polymeric systems waterPolymeric systems water--cosolventscosolvents with peculiar viscoelasticwith peculiar viscoelastic properties for selective and controlled cleaning of easel paintingsproperties for selective and controlled cleaning of easel paintings

5

Decay of painting layers from coherent porous material

to incoherent granular matter

Many factors among which the most important atmospheric pollution

determine the loss of adhesioncohesion properties originating

surface powdering

lifting and bowls of painting layers

surface opacification (light scattering)

NEED OF PRE-CONSOLIDATION

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

4

CaCa(OH)(OH)22 nanoparticles with high degree of physicochemicalnanoparticles with high degree of physicochemical compatibility for consolidationprotection ofcompatibility for consolidationprotection of wall paintings and wall paintings and limestoneslimestones MicellarMicellar systems and watersystems and water--based based microemulsionsmicroemulsions -- green systemsgreen systems -- for cleaning architectonicartistic surfaces for cleaning architectonicartistic surfaces Polymeric systems waterPolymeric systems water--cosolventscosolvents with peculiar viscoelasticwith peculiar viscoelastic properties for selective and controlled cleaning of easel paintingsproperties for selective and controlled cleaning of easel paintings

5

Decay of painting layers from coherent porous material

to incoherent granular matter

Many factors among which the most important atmospheric pollution

determine the loss of adhesioncohesion properties originating

surface powdering

lifting and bowls of painting layers

surface opacification (light scattering)

NEED OF PRE-CONSOLIDATION

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

5

Decay of painting layers from coherent porous material

to incoherent granular matter

Many factors among which the most important atmospheric pollution

determine the loss of adhesioncohesion properties originating

surface powdering

lifting and bowls of painting layers

surface opacification (light scattering)

NEED OF PRE-CONSOLIDATION

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

6

Piero della Francesca (15th century) particular of the

The Legend of the True Cross St Francis Church Arezzo

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

7

The art of materials science Ca(OH)2 as

perfect art-compatible binding agent

The best pre-consolidating agent based

on the golden rule of physicochemical

compatibility

Slaked lime as a paste containing Ca(OH)2

plus water (ca 50 by weight)

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

8

Saturated aqueous (lime water) too lsquoweakrsquo as re-

establishing agents for the mechanical properties due to

the very low Portlandite solubility

(16 gL-1)

Dispersions or suspensions in water (lime milk) too

kinetically unstable originating fast particles settling and

consequent glazing on the painted surfaces

Problems associated to the use of Ca(OH)2

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

9

Research strategy

Ca(OH)2 dispersions instead of saturated aqueous solutions to

increase the binder concentration short chain aliphatic alcohols as

dispersant media instead of water and finally

Ca(OH)2 nanoparticles to increase the dispersions kinetic stability and

favour binder penetration within the pictorial layers

Giorgi R Giorgi R L Dei and P Baglioni A New Method for consolidating Wall Paintings and P Baglioni A New Method for consolidating Wall Paintings based on Dispersions of Lime in Alcohol based on Dispersions of Lime in Alcohol Studies in ConservationStudies in Conservation 45 (2000) 154 45 (2000) 154

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

10

Expected advantages of an approach

based on the art of nanoscience

Better penetration of the consolidating agent into

the painting layers

Strong reduction of possible white glazing

Smaller pores filled in by the binder Ca(OH)2

particles

In conclusion improved performance of the art-

compatible consolidating agent

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

11

Bottom-to-top strategy synthesis of Ca(OH)2

nanocrystals method 1

In homogeneous phase at 90 degC by reaction between aqueous solutions of NaOH and CaCl2 at supersaturation degree between 3 and 10

vN gtgt vG

warrants small crystals

(hexagonal prisms with a few nm height) Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

12

Nucleation rate wk = exp-C[ln(CoCs)]

2 wk probability of nuclei formation

CoCs = S supersaturation degree

C constant depending on r g PM e T

vN = dxdt = Aexp-[(DG + q)kBT] x nuclei concentration

A frequency factor

DG Gibbs free energy for nuclei formation

q activation energy for ionic couples diffusion across the interface

Yasuo Arai Chemistry of Powder Production Chapman amp Hall London 1996

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

13

02

1

0 05 1 15 2 25

ln(CoCs)

3 lt S lt 10 wk

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

14

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

15

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

16

10nmI

x and y axes dimensions

1630x1630 nm

x

y

z

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

17

Synthesis of Ca(OH)2 nanocrystals method 2 2

In homogeneous phase by reaction between an aqueous

solution of NaOH and a solution of CaCl2 in diols

(CH2OHCH2OH o CH2OHCHOHCH3) at 150-160 ordmC and with

3 S 10 By this method we reduce size but we need a

peptization subjecting the particles to ultrasounds in 2-propanol

L A Peacuterez-Maqueda I Wang and E Matijevic Nanosize Indium Hydroxide by Peptization of Colloidal

Precipitates Langmuir 14 (1998) 4397

B Salvadori and L Dei Synthesis of Ca(OH)2 Nanoparticles from Diols Langmuir 17 (2001) 2371

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

18

PEPTIZATION

Dispersion in 2-

propanol

Ultrasounds

disperse the

nanoparticles

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

19

B Salvadori and L Dei Synthesis of Ca(OH)2Nanoparticles from Diols Langmuir 17 (2001) 2371

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

20

Cathedral of Santa Maria del Fiore

wall paintings lsquoThe Musician Angelsrsquo

by Santi di Tito (1536-1603)

decorating the inner counterfaccedilade of

the Cathedral

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

21

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

22

Ambrosi M L Dei R Giorgi C Neto and P Baglioni Colloidal Particles of Ca(OH)2 Properties and Applications to Frescoes Restoration Langmuir 17 (2001) 4251

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

23

Nanotechnology restores flaking frescos An off-the-wall application of tiny particles re-unites paint and plaster11 July 2001 PHILIP BALL

A beautiful bottom ndash thanks to the restorative effects of nanotechnology

Piero Baglioni and colleagues from the University of Florence have salvaged a lesser-known work Gli Angeli Musicanti painted in the sixteenth century by Santi di Tito in the Santa Maria del Fiore Cathedral in Florence This image is disfigured where flakes of paint-impregnated plaster having lifted off the wall below are threatening to fall off damaging the painting irreparably Baglioni and his colleagues use humble slaked lime as a kind of glue to re-adhere flaking paint They apply it as a suspension of tiny calcium hydroxide crystals in alcohol Creating such small crystals is one of the objectives of nanotechnology the manipulation of matter at the nanometre level Nanotechnology usually portrayed as the futuristic pursuit of molecular-scale machines has something to

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

24

20 mm

20 mm

Surface re-compacting

Lower water absorption

CaSi

( At)

As

(m2g)

Before 89 plusmn 09 37 plusmn 04

After 183 plusmn 18 27 plusmn 03 0

5

10

15

20

25

30

35

40

0 100 200 300 400

t^05

Mi

10^2

PRIMA

DOPO

_______ Before

----------- After

t05

m(g

)x10

0

Application even on limestones

Dei L and B Salvadori Nanotechnology in Cultural Heritage Conservation Nanometric Slaked Lime saves Architectonic

and Artistic Surfaces from Decay J Cultural Heritage 7 (2006) 110

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

25

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

26

Before

After

Dei L B Salvadori E Arlango F Pietropoli and C Scardellato Proceedings of the XXI International Meeting

ldquoScience amp Cultural Heritage ndash On Wall Paintingsrdquo Brixen (Bozen) Italy July 12-15 2005 Arcadia Ricerche

Publisher pp 293-302

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

27

Lunettes decorated with the Histories of St Helijah and the Carmelite Order in the Cloister of the St Simon and St

Judas Church 30 Km far from Florence painted in 1708 by Gaetano Carrai Present lunette Transfiguration

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

28

Verification of the recovering of the mechanical properties

induced by nanolime application

Before the treatment After 6 applications After 12 applications 0

02

04

06

08

1

12

14

16

0 6 12

Number of applications

ST

T (

mg

cm

2)

STT 1b

STT 2b

STT 3b

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

29

The legend of the Sacral Wood (1380) Agnolo Gaddi

St Croce Basilica Florence Major Chapel

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

30

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

31

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

32

WHATrsquoS A GEL

Brinker JC Scherer GW Sol-Gel Science Academic Press New York 1990

laquo We interpret a gel to consist of continuous solid and fluid phases of colloidal

dimensions Continuity means that one could travel through the solid phase from

one side of the sample to the other without having to enter the liquid conversely

one could make the same trip entirely within the liquid phase raquo

Black rods colloidal solid

polymer strands

Open circles cross-links

White region colloidal fluid

phase

Red line trip through the solid

phase

Blue line trip through the fluid

phase

Tens of nm

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

33

LESS EMPIRICAL DEFINITION

MECHANICAL PROPERTIES

MECHANICAL ENERGY STORED (SHEAR

STORAGE MODULUS Gprime) versus

MECHANICAL ENERGY DISSIPATED

(SHEAR LOSS MODULUS Gprimeprime)

GE

L =

VIS

CO

EL

AS

TIC

SY

ST

EM

S

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

34

laquo A gel is a solid or a semisolid material which consists of at least two

components one of which is a liquid and that it is soft and resilient The latter

property means that the mechanical damping

tan = Gprimeprime(w)Gprime(w) ltlt 1

in the material is small raquo Almdal et al Polymer Gels and Networks 1 (1993) 5

For a gel most of the

mechanical energy

furnished is stored the rest dissipated that is

Gprime(w) gtgt Gprimeprime(w)

F Chambon Z S Petrovic W J MacKnight H Henning Winter Rheology of Model Polyurethanes at the

Gel Point Macromolecules 1986 19 2146-2149

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

35

Poly(acrylic acid) PAA gel Poly(vinyl alcohol)-borate system

E Carretti S Grassi M Cossalter I Natali G Caminati P Baglioni R G Weiss L Dei Poly(vinyl alcohol)-borate

HydroCosolvent Gels Viscoelastic Properties Solubilizing Power and Application in Art Conservation Langmuir 25

(2009) 8656-8666

GEL = Gprime gtgt Gprimeprime in the whole range of frequency

w c

Gprimeprime

Gprime

w c = cross-over frequency

Gprimeprime

Gprime

So that hellip

PAA systems are GELS whereas PVA-borate ones are

highly viscous polymeric dispersions

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

36

minimize the minimize the

penetration of the

solvent

GELS OR HIGHLY VISCOUS POLYMERIC DISPERSIONS

SOLVENT(S) ldquoTHICKENEDrdquo BY SUITABLE MOLECULES

CALLED ldquoTHICKENING AGENTSrdquo

when optically when optically

transparent minimize the minimize the

evaporation of

dispersed phase

control of the control of the

cleaning action IMPROVED IMPROVED

PERFORMANCE

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

37

PROBLEMS WITH TRADITIONAL GELS

AS RESIN SOAP OR SOLVENT GEL

COMPLETE REMOVAL OF GELATOR (ldquoTHICKENING AGENTrdquo)

ACHIEVED BY MEANS OF

bull washing with solvent mixtures

with the consequence of gelator residues

Stulik et al Solvent Gels for the Cleaning of Works of Art

The Residue Question V Dorge (ed) Getty Conservation Institute 2004

Goal easy removal

Strategy elasticity versus viscosity

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

38

PVABorax systems

Poly (vinyl alcohol) PVA

Borax Na2B4O710H2O

Water (Organic cosolvent)

CH3

CH3

OH

OH

B-

OH

OH

OH

OH

+ +

-4 H2OCH3

CH3

OH

OH

B-

CH3

CH3

O

O

CH3

CH3

O

O

PVA chains

Cross linking

induced by

borate ions

Lin H-L et al Polymer 2005 46 5541-5549

Carretti et al Langmuir 2009 25 8656-8662

High shear storage (elastic) modulus Gprime

depending on both PVA and borax

concentration

B-

B-

Na+

Na+

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

39

Polyvinylalcohol-borate hydrogels incorporating cosolvents

001 01 1 10 1001

10

100

1000

G

G [

Pa]

Com

plex

Vis

cosi

ty [P

a x

s]

w [1s]

A

100

10000

Loss modulus Gprimeprime

Storage modulus G

PVA 3 BORATE 06 PVA 2 BORATE 03 TRADITIONAL POLYACRYLIC GEL

ALL GELS CONTAIN 20 1-PROPANOL

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

40

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

41

Nature Materials June 2009 - Vol 8 (6)

Research Highlights ldquoHydrogels clean uprdquo

Poly(vinyl alcohol)minusBorate HydroCosolvent Gels Viscoelastic

Properties Solubilizing Power and Application to Art Conservation

Emiliano Carretti Scilla Grassi Manuela Cossalter Irene Natali

Gabriella Caminati Richard G Weiss Piero Baglioni and Luigi Dei

Langmuir 25 (2009) 8656

Carretti E E Fratini D Berti L Dei P Baglioni Nanoscience for Art

Conservation Oil Droplets in Hydrogel for the Cleaning of Works of Art

Angewandte Chemie 48 (2009) 8966

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

42

ldquoIncoronazione della Vergine con Santirdquo

by Neri di Bicci (XV secolo)

Two superimposed layers

1 Brown rough clots

2 Dark texture underneath strongly bound to the painting layer

2 1

+2

2

1

Oxidized shellac

+ white egg

based varnishes

Photochemical aging

time (h)

of shellac resin

brown

coating

from

painting

0 120 240 Natural

aging

n (cm-1) C-O stretch 1251 1249 1246 1245

A~1250A1141-1171 163 112 100 095

Resolution of peaks at 1141

and 1171 cm-1

yes no no no

Shoulder at ~1245 cm-1 yes yes no no

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

43

E Carretti I Natali C Matarrese P Bracco R G Weiss P Baglioni A Salvini L Dei A

New Family of High Viscosity Polymeric Dispersions for Cleaning Easel Paintings J

Cultural Heritage J Cultural Heritage 11 (2010) 373-380

E Carretti M Bonini L Dei B H Berrie L V Angelova R G Weiss and P Baglioni New

Frontiers in Materials Science for Art Conservation Responsive Gels and Beyond Acc

Chem Res 43 (2010) 751-760

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

44

Structural and Mechanical Properties of ldquoPeelablerdquo Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks Applications to Cleaning Painted Surfaces

Irene Natali Emiliano Carretti Lora Angelova Piero Baglioni Richard G Weiss and Luigi Dei

Langmuir 27 (21) (2011) 13226

Cover of the issue 21 vol 27Cover of the issue 21 vol 27 November 1November 1stst 2011 2011

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

45

Conclusion

Chemical sciences not only to understand ldquowhy does it occur what occursrdquo (diagnostics and causes of the decay processes) but also to mould matter so that ldquoit can occur what we want that occurrdquo (the art of materials science for the conservation of art)

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

46

Acknowledgments bull Dott Arch M Lolli Ghetti Dottssa L M Medri Dott A Bisceglie Drs C Acidini C

Masdea M Sframeli M Simari Cultural Heritage Ministry Local Offices of Firenze Pistoia

and Prato

bull Dottssa A M Spiazzi Dott F Pietropoli C Scardellato Cultural Heritage Ministry Local

Offices of Verona

bull Dottsse C Acidini C Danti Dott G Lanterna C Frosinini Opificio delle Pietre Dure

bull Conservators G Calamandrei E Arlango Dott A Felici P Mariotti F Bandini M R

Lanfranchi Prof I Hammer S Engelmann D Venzlaff L Cinelli D Rossi P Bracco K

Nakahara

bull Profs E Ferroni P Baglioni Ivo Hammer G Caminati

bull Mrs Daniela Ristori International University of Art Foundation Florence

bull Prof Richard G Weiss Chemistry Department at Georgetown University Washington DC

bull Prof Antonella Salvini Department of Chemistry lsquoUgo Schiff lsquo University of Florence

bull Dr Susanna Bracci CNR-ICVBC Florence

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

47

But the deepest and sincerest gratitude is for pupils andBut the deepest and sincerest gratitude is for pupils and students who worked on these projectsstudents who worked on these projects

Rodorico Giorgi Moira Ambrosi Emiliano Carretti Barbara Salvadori Azzurra Macherelli Marcello Mauro Valentina Errico Giovanna Bitossi Paola Croveri Alessandra Nuccio Fabrizio Andriulo Irene Natali Scilla Grassi Manuela Cossalter Caterina Matarrese Caterina Palpacelli Serena Balducci Chiara Berlangieri Anna Ballerini Alice Fietta Elisa

Ghelardi Federica Marinelli Eliana Costa Francesca Giambi Mariangela Potenza (Italia)

Lora Lora AngelovaAngelova (Bulgaria(Bulgaria--USA)USA)

Paula Del Valle Paula Del Valle BartolomeacuteBartolomeacute Maria Del Carmen Llopis Enrique ((EspanaEspana))

George Mathew Brooke George Mathew Brooke RosenzweigRosenzweig Elizabeth Elizabeth MelnikMelnik (USA)(USA) Kristine Kristine Ehlers Sigrid Engelmann Damar Venzlaff (Deutschland) EstelleEstelle MoretMoret Carine Michel Carine Michel (France) Maria Rosario De Marcelino (Portugal)

since without them this lecture would be never bornsince without them this lecture would be never born

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention

48

ldquoMuch has already been found but what we have still to ldquoMuch has already been found but what we have still to find is more And this means other workfind is more And this means other work

for new generations for new generations rdquordquo

from ldquoGalileorsquos Liferdquo by Bertolt Brecht

Thanks for attention Thanks for attention