the art of nanoscience for the conservation of...
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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
top related