multidetector field flow fractionation for the ... event/2015/related... · multidetector field...

Multidetector Field Flow Fractionation Multidetector Field Flow Fractionation for the Comprehensive Analysis of for the Comprehensive Analysis of

Complex Polymers Complex Polymers

Harald Pasch, Ashwell Makan, Margareta Brand, Nyasha Ngaza, Guilaume Greyling

SASOL Chair of Analytical Polymer ScienceDepartment of Chemistry and Polymer Science, University of Stellenbosch, South Africa

1

BackgroundBackground

Problems:Problems:

Limited towards higher molar masses

Shear degradation (mechanical stress due to(mechanical stress due to stationary phase

Separation of linear and branched molecules

Adsorption on the stationary phase

Separation according to hydrodynamic volume

SEC Separation

2

BackgroundBackground

Problems:Problems:Column-based chromatography does not

k f

1

work for

polymer nanocomposites

colloids

Vr

2

emulsions

particle suspensions

1

2Composition

Chain Length

3

NanomaterialsNanomaterials

modified clay particlemodified clay particle

Nano to micro

Single wall carbon

nanotubesCH3 S

S

S

CH3

O

ON

+CH3

CH3CH3

1. Ion exchange:

2. polymerization

CH3 S

S

S

CH3

O

ON

+CH3

CH3CH3

1. Ion exchange:

2. polymerization

Unmodified clay particleUnmodified clay particle

4

free polymer

ionically bound polymer

free polymer

ionically bound polymer

Advantages of Field Flow FractionationAdvantages of Field Flow Fractionation

Experimental setup

Higher exclusion limit Colloids, emulsions,

particle suspensions

SEC FFF FFF

SEC 2nm - 100µm Mild conditions: proteins, cells Log M Log M

• channel volume 1-5 mL

Elution Volume

• sample volume 1-500 µL

• sample conc. < 1%5

Field Flow FractionationField Flow Fractionation

Most commonly used types of fieldsMost commonly used types of fields

• Sedimentation: VR = f (M, particle diameter dp)R ( , p p)channel is spun at a right angle to the flow, field strengths similar to ultracentrifuge,separation of colloids 30 nm to 1 µm range

• Thermal: VR = f (D/DT ~ 1/Ma)temperature gradient across the channel, T ~ 80 K, particles are driven towards the

ld ll t l ti

Temperature Field

cold wall, not as mass selective as sedimentation

• Flow: VR = f (D ~ 1/Ma)application of a cross-flow through a semi-permeable membrane, driving force is the viscous force exerted on the particle by the cross stream, based on particle (molecule) size

D - diffusivity; DT - thermal diffusivity

6

The LEGO ApproachThe LEGO Approach

ICP-MS

NMR

AF4AF4

7 DLS FTIR

ThFFFThFFF

SdFFFSdFFF

Applications (AFApplications (AF44 –– MALLS)MALLS)

8

Analysis of High Molar Mass Branched PolybutadienesAnalysis of High Molar Mass Branched Polybutadienes

• polybutadiene rubber is synthesised via Ziegler-Natta catalysis, broad molar mass and branching distributions are obtained, molar masses might reach > 1Mio g/mol

• Initial SEC results obtained showed complete contradiction with processing behaviour

at Mbranched = Mlinear Vhbranched < Vh

linear

Method development for AF4/MALLS and comparison with SEC/MALLS

SBR Rubber

9A.C. Makan, T. Otte, H. Pasch, Macromolecules 45 (2012) 52479

SBR Rubber

ExperimentalExperimental DetailsExperimental Details

Degasser

Waste

Mobile phase

Focus flow pump

Tip flow pump

Waste

MALLS

RI

pump

Cross‐flow pump

Waste

MALLS

Oven @ 25° C

Mylar foil with AF4 channel cut‐out

A BCross‐section view

Stainless steelplates Porous frit

with cellulose membrane

PolybutadienePolybutadiene samples• Rubber dissolved in HPLC grade THF at 3 mg/mL• BHT stabilizer (1mg/mL) • Dissolution steps:

Di l i f 16h RTCross‐flow field

DiffusionB > A

Cross section view of the channel

SEC columns DetectorsTip pump

- Dissolution for 16h at RT- Heated at 50°C for 4 hrs- 0.2µm and 0.45µm filters SEC, FFF- Unfiltered injection in FFF

AF4-instrument (Postnova Analytics, Landsberg/Germany)

MALLS - (Dawn DSP, Wyatt Technology, Santa Barbara, USA) RI detector (PN 3140, Postnova Analytics, Landsberg/Germany)

1010

Two columns (PL mixed B + mixed C) for SEC

100 µL sample loop for both methods

Constant Detector flow rate of 0.5 mL/min

SEC: Effect of different dissolution stepsAnalysis of High Molar Mass PolybutadienesAnalysis of High Molar Mass Polybutadienes

Molar mass Molar mass

Branching? Dissolution?

Chain Scission?

Gels? Molecular

Aggregates? Entanglements?

Gels? Molecular

Aggregates? Entanglement?

Entanglements?

A.C. Makan, T. Otte, H. Pasch, Macromolecules 45 (2012) 524711

Comparison SEC vs. AFComparison SEC vs. AF44 of Polybutadieneof Polybutadiene

Molar MassMolar MassR.M.S RadiusR.M.S Radius

SECFFF

FFF

SEC

SECFFF Slope FFF = 0.43

(randomly branched)

Randomly branched

Slope SEC= 0.36

Randomly branchedPS = 0.45

Linear = 0.588

(no physical meaning)

Conformation plotConformation plot12

Size Analysis of Polyrotaxanes: SECSize Analysis of Polyrotaxanes: SEC

0 5089 mg/mlMolar Mass (SEC)

0.24

0.28

volts

)

0.5089 mg/ml 1.0384 mg/ml 1.9374 mg/ml 3.6174 mg/ml

1.0x108Molar Mass (SEC)90o LS signal

Normal SEC behaviour

Abnormal SEC behaviour

0 12

0.16

0.20

Mas

s (g

/mol

)

terin

g S

igna

l (v

1.0x107

behaviour

0.04

0.08

0.12

Mol

ar M

90o L

ight

Sca

tt

1.0x106

Samples: G. Wenz, University of Saarbruecken, Germany

20 24 28 32 360.00

0.049

Retention time (min)

1.0x105

13

Size Analysis of Polyrotaxanes: AFSize Analysis of Polyrotaxanes: AF44

2.0

0.5089 mg/ml 1.0384 mg/ml 1.9374 mg/ml

Molar Mass (AF4)90o LS signal 1.0x1010

1.4

1.6

1.8 3.6174 mg/ml

(vol

ts)

1.0x108

1.0x109

)

Perfect molar mass

separation

0 8

1.0

1.2

erin

g S

igna

l

1.0x106

1.0x107

Mas

s (g

/mol

)

0.4

0.6

0.8

0o Ligh

t Sca

tte

1 0x104

1.0x105

1.0x10

Mol

ar M

4 8 12 16 20 24 28 320.0

0.290


1.0x103

1.0x10


H. Pasch, A.C. Makan, H. Chirowodza, N. Ngaza, W. Hiller, Anal. Bioanal. Chem. 406 (2014) 1585-159614

Size Analysis of Polyrotaxanes: SEC and AFSize Analysis of Polyrotaxanes: SEC and AF44

0.24

0.28

s)


R.M.S. Radius (SEC)90o LS signal

1 2 3

100Observed elugram

0.12

0.16

0.20

90o s

igna

l (V

olts

Rg (n

m)

1 2 3

10

20 24 28 32 360.00

0.04

0.08

MA

LLS

9 R

1SEC

Rg nten

sity

Rg1 Rg2

20 24 28 32 36


1.41.61.82.0

Vol

ts)


R.M.S. Radius (AF4)90o LS signal

100

1000

R

Sign

al in

0.60.81.01.21.4

LS 9

0o sig

nal (

V

Rg(n

m)

10

100

Elution volume (mL)

4 8 12 16 20 24 28 32

0.00.20.4

MAL

L


1

FFFElution volume (mL)

FFF Separation of NanoparticlesFFF Separation of Nanoparticles

FTIR

16

Nanoparticle GraftingNanoparticle Grafting

PolystyrenePolystyrene--Laponite GraftingLaponite Grafting

modified clay particlemodified clay particlemodified clay particle

N+CH3

CH3C

N+CH3

CH3C

free clay particle

How to analyze such complex graft materials ?

- number of PS chains per Laponite

- molar masses of grafted and non-grafted PS

17

g g

- Separation of grafted and non-grafted Laponite

AF4 of PolystyreneAF4 of Polystyrene--Laponite NanocompositeLaponite Nanocomposite

LS 90oA

F r a c t i o n 3

gnal

dRI

= C – H

– C – H

S i – OC = C

o o p C H22

Det

ecto

r sig

3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0

w a v e n u m b e r s ( c m - 1 )

o o p C – H

Fraction 4

aromatic overtones

0 10 20 30 40 50 60

Retention time (min)F r a c t i o n 1

Si–O–C–H

=C–H C=O

C–O33

18 3 5 0 0 3 0 0 0 2 5 0 0 2 0 0 0 1 5 0 0 1 0 0 0

w a v e n u m b e r s ( c m - 1 )

= C – H – C – HC = C

o o p C – H11

AF4 of PolystyreneAF4 of Polystyrene--Laponite NanocompositeLaponite Nanocomposite

LS 90oANot exfoliated grafted particles

gnal

dRI

Det

ecto

r sig

CH3

modified clay particle

CH3

modified clay particle

0 10 20 30 40 50 60


N+CH3

CH3C

N+CH3

CH3C

19

FFFFFF Separation of Polymer EmulsionsSeparation of Polymer Emulsions

ICP-MS

DLS

20

WaterWater--Based Decorative CoatingsBased Decorative Coatings

Water-Based Decorative Paint

TiO2, CaCO3 and other inorganics

Binder/emulsion/latexAdditives: surfactants,

biocides,rheology modifiers tg etc.

Additives

Common defects:cracking, peeling, chalking

21

cracking, peeling, chalking

May be caused by wrong composition and size of polymer latex

Latex Preparation: Emulsion PolymerizationLatex Preparation: Emulsion Polymerization

5 % added

Formation of in-situ seed

Pre-emulsion:water, surfactant,

Water, buffer, surfactant,shot of initiator

Sample Details Hour1 After in-situ seed formation for 7 minutes 02 30 minutes after feed started 0.5

3 1 hour after feed started 1

4 1 5 h ft f d t t d 1 5

ate , su acta t,BA, MMA, MAA

4 1.5 hours after feed started 1.5

5 2 hours after feed started 2

6 2.5 hours after feed started 2.5

7 3 hours after feed started 3

8 Monomer feed ends 3 5

22

8 Monomer feed ends 3.59 20 minutes after delayed initiator 4

10 4.5 hours after feed was started – Post treatment started 4.5

11 Final particle size 6

Polymer Latex AnalysisPolymer Latex Analysis

Experimental approach: AF4

DLS analysis of bulk samples

particle growth until the end

23

of monomer addition

Polymer Latex Analysis: AF4Polymer Latex Analysis: AF4--UVUV--RIRI--MALLSMALLSRI signal

90o MALLS signal

UV 254 nm signalsignal

24

Polymer Latex Analysis: AF4 vs. SdF3Polymer Latex Analysis: AF4 vs. SdF3

Sedimentation: VR = f (M, particle density, particle diameter dp)

Flow: VR = f (D ~ 1/Ma)

25

Polymer Latex + TiOPolymer Latex + TiO22 Analysis: AF4Analysis: AF4--UVUV--RIRI--MALLSMALLS--ICPICP--MSMS

Size distribution of polymer latex particles

andand

quantitative analysis of TiO2 content

26

AF4AF4

ThFFFThFFF

SdFFFSdFFF

27

AF4AF4--MALLS and offline MALLS and offline NMRNMR of PSof PS--PI Block CopolymerPI Block Copolymer

R1 CH2 CH CH2 C

CH3

CH CH2 R2

m n

PSPS--PIPI

PIPI Multi PSMulti PS--PIPIMulti PSMulti PS PIPI

A. Makan, P. Sinha, N. Ngaza, W. van Aswegen, H. Pasch, Anal. Bioanal. Chem. 405 (2013) 9041-9047 28

Online Coupling of Online Coupling of FFFFFF and and 11HH--NMRNMRp gp g

Temperature Fi ldField

ThFFFThFFF--NMR of PI, PS and PMMANMR of PI, PS and PMMA

S l bSame molar masses but different elution volumes

for PI and PS/PMMA

UniversalUniversal calibration

ThFFF SEC

30

ThFFFThFFF--NMR of Block CopolymersNMR of Block Copolymers

Uniform chemical composition as a function of molar mass

Clear indication for fractions of different chemical compositions

31W. Hiller, W. van Aswegen, M. Hehn, H. Pasch, Macromolecules 46 (2013) 2544-2552

ThFFF OnThFFF On--flow Coupling to NMRflow Coupling to NMR

Specific chemical shift regions for all monomers

monomer composition as a function of FFF separation profilemonomer composition as a function of FFF separation profile

32W. van Aswegen, W. Hiller, M. Hehn, H. Pasch, Macromol. Rapid Commun. 34 (2013) 1098-1103

ThermalThermal FFFFFF Separations of PSSeparations of PS PEOPEOThermal Thermal FFFFFF Separations of PSSeparations of PS--PEOPEOBlock Copolymers in Solvents of Different Block Copolymers in Solvents of Different

Thermodynamic QualityThermodynamic Quality

33

ThFFF of PS and PEO in ChloroformThFFF of PS and PEO in Chloroform

107

108 1.5

PS 132 kDa PS 275 kDa PS 1 412 kDa

105

106

Mol

ar m

ass

(g/m

ol)

0.5

1.0

RI s

igna

l (V

)

10 20 30103

104

M


0.0

107 0.8 PEO 81.9 kDa PEO 289 kDa PEO 1 015 kDa

good solvent = random coil conformation

105

106

Mol

ar m

ass

(g/m

ol)

0.4

0.6

RI s

igna

l (V

)

0 10 20 30104

Retention time(min)

0.2

N. Ngaza, M. Brand, H. Pasch, Macromol. Chem. Phys. 216 (2015) 1355-1364

ThFFF of PSThFFF of PS--bb--PEO, PS and PEO in ChloroformPEO, PS and PEO in Chloroform

1.0

PEO 289 kDa PS 275 kDa PS-b-PEO 218 kDa

108

0.8

V)

106

107

g/m

ol)

0.4

0.6

RI s

igna

l (

105

Mol

ar m

ass

(g

5 10 15 20 25

0.2103

104

All samples have similar molar masses

5 10 15 20 25


difference in TR is due to different DT


ThFFF of PS and PEO in THFThFFF of PS and PEO in THF

107 3.5 PEO 289 kDa PS 275 kDa THF is a good solvent for PS

= random coil conformation

105

106

ss (g

/mol

)

2.5

3.0

0° s

igna

l

104Mol

ar m

as

1.5

2.0

MAL

LS 9

0

THF i l t f PEO0 10 20 30 40 50 60

103


THF is a poor solvent for PEO = collapsed coil conformation

Sample Nominal Mp

[kg/mol]

D x 10-7

[cm2/s]

DT x 10-7

[cm2/s K]

PS3 275 0 2 00± 0 05 0 48± 0 01PS3 275.0 2.00± 0.05 0.48± 0.01

PEO3 289.0 2.97± 0.13 0.34± 0.02


ThFFF of PSThFFF of PS--bb--PEO, PS and PEO in THFPEO, PS and PEO in THF

PS-b-PEO has a 30 kDa PS block

106

0.7

0.8

PS 132 kDa PS-b-PEO 91.5 kDa PS 29.5 kDa

and a 61.5 kDa PEO block105

s (g

/mol

)

0.4

0.5

0.6

al (V

)

104

Mol

ar M

ass

0.1

0.2

0.3

RI s

igna

0 10 20 30 40 50 60103


0.0

PS block in random coil conformation and PEO block in collapsed conformation

Corona polymer (PS)

Sample D x 10-7 [cm2/s] DT x 10-7 [cm2/s K]

PS1 (30 kDa) 7.93± 0.15 0.63± 0.04

PSPEO1 5 47± 0 18 0 61± 0 03 dominates elution behaviourPSPEO1

(30-61.5 kDa)

5.47± 0.18 0.61± 0.03


ThermalThermal FFFFFF as a Selecti e Tool foras a Selecti e Tool forThermal Thermal FFFFFF as a Selective Tool for as a Selective Tool for Microstructure SeparationsMicrostructure Separations

What is the Limit of What is the Limit of FFFFFF Selectivity ?Selectivity ?

38

HPLC Separation of PS by Degree of DeuterationHPLC Separation of PS by Degree of Deuteration

Separation of similar molar masses and chemical structures the only difference being the deuteration

39 P. Sinha, G. Harding, K. Maiko, H. Pasch, J. Chromatogr. A 1265 (2012) 95-104

Microstructure Analysis of PMMA by 2DMicrostructure Analysis of PMMA by 2D--LCLC

0 014

0.016

0.018

0.020

0 002

0.004

0.006

0.008

0.010

0.012

0.014

ELS

D S

igna

l

2 4 6 8 10-0.002

0.000

0.002

SGIC Elution volume (ml)

0 018

0.008

0.010

0.012

0.014

0.016

0.018

SD

Sig

nal

2 4 6 8-0.002

0.000

0.002

0.004

0.006ELS

SEC Elution volume (ml)

K. Maiko, M. Hehn, W. Hiller, H. Pasch, Anal. Chem. 85 (2013) 9793-9798

ThF3ThF3 for Microstructure Fractionation of PI and for Microstructure Fractionation of PI and PBPB

Polybutadiene isomers

1,4-PB

1,2-PB

ThFFFSolvent: Cyclohexane∆T = 60 °C, Cold wall = 24 °C

1,4 1,2

Polyisoprene isomers

1,4-PI

3,4-PI 1 4 3 4

41

3,4 PI

G. Greyling, H. Pasch, Macromol. Rapid Commun. 35 (2014) 1846-1851

1,4 3,4

ThF3ThF3 for for TacticityTacticity Fractionation of Fractionation of PMMAPMMA

*

*

H H H HH H H H

rrr

CH3 COOCH3 CH3 COOCH3

H3COOC H3C H3COOC H3C

*

*

H H H H

CH CH COOCH CH

H H H H

H H H HH H H H

mrr

CH3 CH3 COOCH3 CH3

H3COOC H3COOC H3C H3COOC

mmm

**

CH3CH3CH3CH3

H3COOCH3COOCH3COOCH3COOC

42

mmm

G. Greyling, H. Pasch, Anal. Chem. 87 (2015) 3011-3018

ThF3ThF3 for Fractionation of for Fractionation of PMMAPMMA--bb--PS MicellesPS Micelles

Molecular weight

[kg/mol]

Tacticity content

[mol %]

PS PMMA Total Isotactic Atactic Syndiotactic

iPMMA-PS 60 85 145 92.6 2.8 4.6

sPMMA-PS 60 83 143 1.6 17.1 81.3

Transition

Unimers

T 10 oC

sPMMA-PS

Unimers

MicellesT 30 oC

iPMMA-PS

sPMMA PS

Liposomes

T 30 oC

43G. Greyling, H. Pasch, J. Chromatogr. A 1414 (2015) 163-172

HighHigh--Temperature Temperature FFFFFF Separation Separation of of PolyolefinsPolyolefins

44

FFF Separation of PolyolefinsFFF Separation of Polyolefins

Oven temp.: 145 oCDetector flo rate 0 5 mL/minDetector flow rate: 0.5 mL/minInjection volume: 200 mLMobile phase: TCB

SEC: 2 x PL Olexis

Rg-M HT-AF4 Rg-M HT-SEC 1,4

MMV HT-AF4 MMV HT-SEC

100

g

Ausgleichsgerade - Anstieg = 0,58

m] 0,8

1,0

1,2

Mas

sena

ntei

l

SEC

10

Rg [n

0,2

0,4

0,6

Diff

eren

tielle

r M

Molar mass distribution and conformation plot for NIST SRM 1496

(linear PE)

AF4

T. Otte, H. Pasch, R. Brull, T. Macko, Macromol. Chem. Phys. 2011, 212, 401–410

103 104 105 106 107

10

Molekulargewicht [g/mol]

0,0

45

SEC and AF4 of Branched LDPESEC and AF4 of Branched LDPE

1000 Rg-M HT-AF4 Rg-M HT-SECLinear Fit - Slope = 0.32

MMD HT-AF4 MMD HT-SEC

1000 Rg-M HT-AF4 Rg-M HT-SECLinear Fit Solpe = 0 36

MMD HT-AF4 MMD HT-SEC

Bimodal LDPE ‘Monomodal’ LDPE

100

Linear Fit Slope 0.32

[nm

]

1

Mas

s Fr

actio

n

100

Linear Fit - Solpe = 0.36

[nm

]

1

Mas

s Fr

actio

n

R g

Diff

eren

tial M

R g [

Diffe

rent

ial M

102 103 104 105 106 107 10810

Molar Mass [g/mol]

0

102 103 104 105 106 107 10810

Molar Mass [g/mol]

0

5,02Sample Method M PD5,0

z

2gRSample Method Mw

(kg/mol)(nm)

PD

LDPE 1 HT-AF4 12830 236 31,7

HT-SEC 1769 82 6,5

T. Otte, H. Pasch, R. Brull, T. Macko et al., J. Chromatogr. A 1218 (2011) 4257– 4267

LDPE 2 HT-AF4 6246 117 12,8

HT-SEC 663 64 15,8

46

SummarySummary

Column-based chromatography is limited regarding molecular size and complexity of sampleand complexity of sample

Field flow fractionation is an important alternative method with AF4 addressing molecular size and ThFFF addressing chemical g gcomposition

AF4 is a versatile fractionation method for very large macromolecules polymer nanocomposites and nanoparticlesmacromolecules, polymer nanocomposites, and nanoparticles

ThFFF is complementary to AF4 and provides chemical and microstructure information on complex samples

Similar to column-based chromatography FFF can be coupled easily to molar mass and spectroscopic detectors

47

Thank you for your attention

4848

multidetector field flow fractionation for the ... event/2015/related... · multidetector field...

Documents