Laboratoire de Rhéologie

UMR 5520

Particulate Fluids Processing Centre

Microscopic and Macroscopic Characterization of Aot / Iso-octane / Water

Sheared Lyotropic Lamellar Phases

Ph.D. Viva Voce

Yann AUFFRET

Ecole Doctorale I-MEP2: Mécanique des Fluides, Energétique et Procédés

Université Joseph Fourier – Grenoble 1, France

Department of Chemical and Biomolecular Engineering

The University of Melbourne, Australia

16th of December 2008

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Presentation Outline

I. Lyotropic Lamellar Phases

II. Shear Induced Structural Evolution

III. Non-Linear Viscoelastic Properties

Yann Auffret

3

I. Lyotropic Lamellar PhasesSelf-Assembling Properties of Surfactants

Yann Auffret

Surfactant

(AOT)

Hydrocarbon chains

Polar head

Apolar solvent (Iso-octane)

Polar Solvent (Water)

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I. Lyotropic Lamellar Phases

Yann Auffret

Self-Assembling Properties of Surfactants

vs

ls

a0

s

ss la

vp

0

s

ss la

vp

0

~1/3 ~1/2 ~1

‘SDS-like’‘AOT-like’

5

I. Lyotropic Lamellar Phases

(Tamamushi and Watanabe, Colloid & Polymer Science, 1980)

SAXS patterns along a water dilution line (ESRF – D2AM french CRG beamline)

S0 S1

S2 S3 S4

S5 S6 S7

Lamellar Phases

• L1: Direct Micelles (oil-in-water droplets)

• 2L: Two Distinct Phases

• L2: Reverse Micelles (water-in-oil droplets)

• L+LC: Micelles and Liquid Crystal Coexistence

•LC (H): Hexagonal Liquid Crystal

•LC (D) Lamellar Liquid Crystal

Yann Auffret

Nanoscopic Structural Characterization

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I. Lyotropic Lamellar Phases

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Nanoscopic Structural Properties

Membrane volume fraction:

=/d

d

q0

0

2

qd

d (

Å)

o

A1.24

fit

d

ls≈11Å

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I. Lyotropic Lamellar Phases

Proliferation and ‘alignment’ of topological defects with increasing water content

(Warriner et al., Science, 1996.)

Yann Auffret

Microscopic Properties

=0.41 =0.32=0.79

Circularly polarized light microscopy

Light

P

A

λ/4

λ/4

sample

8Yann Auffret

I. Lyotropic Lamellar PhasesConclusion

o

A1.24

fit

d

Nanoscopic scale:

- Lamellar structures for <0.8

- = 24.1Å 35Å<d<91Å

Microscopic scale:

- Permanent topological defects for <0.5

9Yann Auffret

II. Shear Induced Structural Evolution Transient and Steady Flow

=0.32Defect Rich Lamellar Phase

Complex transient regime

then

apparent steady state

=0.79Defect Poor Lamellar Phase :

Constant stress upon apllication of constant shear rate

Newtonian apparent behavior

=0.4Pa.s

(Auffret et al, Rheologica Acta, 2008.)

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X-ray beamShear cell

110 sg

r

r

ω

Sample

Yann Auffret

II. Shear Induced Structural Evolution Nanoscopic Scale

=0.32

vv

110 s

11Yann Auffret

II. Shear Induced Structural Evolution Microscopic Scale

=0.32

ω

r

P+λ/4 λ/4+AShear cell

g

rloc

110 s

12Yann Auffret

II. Shear Induced Structural Evolution Microscopic Scale

Apparent steady state textures

80ma

Frank’s Theory:2

222

111

a

K

aadt

d

1

asteady state

(Larson and Mead, Liquid Crystals, 1992.)

13Yann Auffret

II. Shear Induced Structural Evolution Macroscopic Effects

=0.32

Strain-controlled

.ss t

.ii t

.oo t

rt

11 130 sg

rs loc

i

ct tt

gtr

)(

Transition at a

critical strain: c

4800c

14Yann Auffret

II. Shear Induced Structural Evolution Conclusion

Rheological behavior of the shear induced ‘phase’?

Nanoscopic scale:

- Shear induced formation of lamellar vesicles

Microscopic scale:

- Strain controlled macroscopic to microscopic

texture transition

Macroscopic scale:

- Strain controlled transient regime

.ss t

.ii t

.oo t

15Yann Auffret

III. Non-linear Viscoelastic Properties Controlled Rheometry?

Invariant apparent steady shear rate

with various surface roughnesses

g=r.tan() gmin~a g=R2-R1

g>>a

80~ma

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Steady State of Reference

Creep Steps Recovery Steps

Applied Stress

init

Tinit Tw Time (s)

step 1 step 2 step 3

Unknown

III. Non-linear Viscoelastic Properties

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time

Recovery step

‘Probing’ step

App

lied

Str

ess

(Pa) 10

0.2

Tinit

preshear

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Steady State of ReferenceIII. Non-linear Viscoelastic Properties

(C. Baravian and D. Quemada, Rheologica Acta, 1998.)

(Auffret et al, Eur. Phys. J. E, to be published)

Maxwell-Jeffrey Model

Inertio-Elastic Response:G

(P

a)

Tinit (s)

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Solid to Fluid Transition

App

lied

Str

ess

Tinit Tw Time (s)

init

app

(Caton and Baravian, Rheol. Acta, 2008)

‘Fluid’ regime Ternary creep

‘Solid’ regime

Primary creep

Solid to fluid transition Secondary Creep

Inertio-Elastic Response

III. Non-linear Viscoelastic Properties

19Yann Auffret

Solid to Fluid Transition

Apparent shear history dependent yield stress

Viscoelastic properties controlled by (init,Tinit,Tw)

Reproducible results on shear history dependent materials

Definition of a ‘true’ steady state of reference

III. Non-linear Viscoelastic Properties

20Yann Auffret

Conclusion

- Multi-scale characterization at rest

• Lamellar phases =24.1Å for <0.8• Permanent topological defects for <0.5

- Shear induced transition in ‘defect rich’ lamellar phase • Lamellar vesicles formation

• Macroscopic to microscopic defects

• Strain controlled process

.ss t

.ii t

.oo t

- Viscoelastic properties of shear-induced lamellar vesicle • Steady state of reference

• Inertio-elastic response analysis

• Solid to fluid transition

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Possible developments

- Confinement effects on rheological properties

- Systematic studies as a function of membrane volume fraction

- origin of topological defects and quantification

- Confinement of ‘macro-molecules’ in such systems

Yann Auffret

Conclusion

22Yann Auffret

Acknowledgement

- I. Pignot-Paintrand, CERMAV, UPR5301, Grenoble

- C. Rochas, Laboratoire de Spectrometrie physique, UMR 5588, Grenoble

- H. Galliard, Laboratoire de Rhéologie, UMR5520, Grenoble

- F. Caton, Laboratoire de Rhéologie, UMR5520, Grenoble

- D. Roux, D.E Dunstan and N. El Kissi (Ph.D Advisors)

Questions?

Thank You for your attention* * * * *

* * * * *

23

I. Lyotropic Lamellar Phases

X-ray Wave

Anisotopic Lamellar Structures

Scattered waves

Scattering pattern

Isotropic Structures

X-ray Wave

Scattered waves

Scattering pattern

d

d

Yann Auffret

Nanoscopic Structural Characterization

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I. Lyotropic Lamellar Phases

Unpolarized white light source

Linear polarizers θ=0°

Plane polarized light

Linear polarizers θ=90°

Unpolarized white light source

No light

α=0

α

Isoclines

Extinction of all wavelengths for:

=0 or =/2

α

Isochromes

Extinction of a given wavelength for:

n.e=k.

Yann Auffret

A

λ

πΔn.eα.II 22

0 sin2sin

α

P

n1n2

e

Microscopic Properties

25

I. Lyotropic Lamellar Phases

Unpolarized white light source

Linear polarizer

θ=0°

λ/4 waveplate

θ=45°

sample λ/4 waveplate

θ=-45°

Linear Analyzer

θ=90°

Microscope or wide lens camera

Without λ/4 waveplates With λ/4 waveplates

Addition of λ/4 waveplates:

α(t)≈ω.t with ω>>1

P

A

P

A

ω

Yann Auffret

Microscopic Properties

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II. Shear Induced Structural Evolution Shear rheometry

Yann Auffret

sPat

t .),(

),( 12

Shear rate: 10 sh

V

Shear stress: Pas

F12

Shear Viscosity:

Usual Shear Cells

Strain-controlled mode:

- Constant applied angular velocity

- Torque evolution

Stress controlled mode:

- Constant applied torque

- Angular displacement evolution

27Yann Auffret

III. Non-linear Viscoelastic Properties Controlled Rheometry?

20Pa

40Pa

Constant apparent shear rate for:

g>>a

Invariant apparent steady shear rate

with various surface roughnesses

g=r.tan()

gmin~a

g=R2-R1

g>>a

80~ma

28Yann Auffret

Recovery Time EffectsA

pplie

d S

tres

s (P

a)

10

0.2

Tw

init

Inertial Coupling Analysis

Tw=0s Tw=9hours

III. Non-linear Viscoelastic Properties