laboratoire de rhéologie umr 5520
DESCRIPTION
Particulate Fluids Processing Centre. 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. - PowerPoint PPT PresentationTRANSCRIPT
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
2
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)
4
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
6
I. Lyotropic Lamellar Phases
Yann Auffret
Nanoscopic Structural Properties
Membrane volume fraction:
=/d
d
q0
0
2
qd
d (
Å)
o
A1.24
fit
d
ls≈11Å
7
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.)
10
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
16Yann Auffret
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
Yann Auffret
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)
18Yann Auffret
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* * * * *
* * * * *
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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
26
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