Laboratoire de Rhéologie UMR 5520

1. 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 Microscopic and Macroscopic Characterization of Aot / Iso-octane / Water Sheared Lyotropic Lamellar Phases Yann AUFFRET Ph.D. Viva Voce 16th of December 2008 Laboratoire de Rhéologie UMR 5520

2. Presentation Outline Yann Auffret • Lyotropic Lamellar Phases • Shear Induced Structural Evolution • Non-Linear Viscoelastic Properties

3. I. Lyotropic Lamellar Phases Apolar solvent (Iso-octane) Hydrocarbon chains Surfactant (AOT) Polar head Polar Solvent (Water) Yann Auffret Self-Assembling Properties of Surfactants

4. I. Lyotropic Lamellar Phases ‘SDS-like’ ‘AOT-like’ vs ~1/3 ~1/2 ~1 ls a0 Yann Auffret Self-Assembling Properties of Surfactants

5. I. Lyotropic Lamellar Phases S0 S1 S2 S3 S4 S5 S6 S7 Lamellar Phases SAXS patterns along a water dilution line (ESRF – D2AM french CRG beamline) Yann Auffret Nanoscopic Structural Characterization (Tamamushi and Watanabe, Colloid & Polymer Science, 1980) • 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

6. I. Lyotropic Lamellar Phases ls≈11Å  q0 d (Å)  Yann Auffret Nanoscopic Structural Properties d Membrane volume fraction: =/d

7. I. Lyotropic Lamellar Phases =0.79 =0.41 =0.32 A λ/4 sample λ/4 P Light Yann Auffret Microscopic Properties Circularly polarized light microscopy Proliferation and ‘alignment’ of topological defects with increasing water content (Warriner et al., Science, 1996.)

8. I. Lyotropic Lamellar Phases Yann Auffret Conclusion Nanoscopic scale: - Lamellar structures for <0.8 -  = 24.1Å 35Å<d<91Å Microscopic scale: - Permanent topological defects for <0.5

9. II. Shear Induced Structural Evolution Defect Poor Lamellar Phase : =0.79 Constant stress upon apllication of constant shear rate Newtonian apparent behavior =0.4Pa.s Defect Rich Lamellar Phase =0.32 Complex transient regime then apparent steady state Yann Auffret Transient and Steady Flow (Auffret et al, Rheologica Acta, 2008.)

10. II. Shear Induced Structural Evolution ω r X-ray beam Shear cell Sample Yann Auffret Nanoscopic Scale =0.32

11. II. Shear Induced Structural Evolution ω r P+λ/4 λ/4+A Shear cell Yann Auffret Microscopic Scale =0.32

12. II. Shear Induced Structural Evolution Frank’s Theory: steady state (Larson and Mead, Liquid Crystals, 1992.) Yann Auffret Microscopic Scale Apparent steady state textures

13. II. Shear Induced Structural Evolution Strain-controlled rt Transition at a critical strain: c Yann Auffret Macroscopic Effects =0.32

14. II. Shear Induced Structural Evolution Yann Auffret Conclusion Nanoscopic scale: - Shear induced formation of lamellar vesicles • Microscopic scale: • Strain controlled macroscopic to microscopic • texture transition Macroscopic scale: - Strain controlled transient regime Rheological behavior of the shear induced ‘phase’?

15. III. Non-linear Viscoelastic Properties g=r.tan() gmin~a g=R2-R1 g>>a Yann Auffret Controlled Rheometry? Invariant apparent steady shear rate with various surface roughnesses

16. III. Non-linear Viscoelastic Properties step 1 step 2 step 3 Applied Stress init Unknown Tinit Tw Time (s) Creep Steps Recovery Steps Yann Auffret Steady State of Reference

17. III. Non-linear Viscoelastic Properties preshear 10 Recovery step Applied Stress (Pa)‏ time 0.2 ‘Probing’ step Tinit Inertio-Elastic Response: Maxwell-Jeffrey Model G (Pa) Tinit (s) (C. Baravian and D. Quemada, Rheologica Acta, 1998.) (Auffret et al, Eur. Phys. J. E, to be published) Yann Auffret Steady State of Reference

18. III. Non-linear Viscoelastic Properties init Applied Stress app Tinit Tw Time (s) ‘Solid’ regime Primary creep Solid to fluid transition Secondary Creep ‘Fluid’ regime Ternary creep Inertio-Elastic Response Yann Auffret Solid to Fluid Transition (Caton and Baravian, Rheol. Acta, 2008)

19. III. Non-linear Viscoelastic Properties Definition of a ‘true’ steady state of reference Reproducible results on shear history dependent materials Viscoelastic properties controlled by (init,Tinit,Tw) Apparent shear history dependent yield stress Yann Auffret Solid to Fluid Transition

20. 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 • Viscoelastic properties of shear-induced lamellar vesicle • Steady state of reference • Inertio-elastic response analysis • Solid to fluid transition Yann Auffret

21. Conclusion Yann Auffret 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

22. Acknowledgement Yann Auffret • 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) * * * * * Thank You for your attention Questions? * * * * *

23. I. Lyotropic Lamellar Phases Isotropic Structures d Scattered waves Scattering pattern X-ray Wave Scattered waves Anisotopic Lamellar Structures Scattering pattern X-ray Wave Yann Auffret Nanoscopic Structural Characterization d

24. I. Lyotropic Lamellar Phases Isochromes P Extinction of a given wavelength  for: Unpolarized white light source Unpolarized white light source  A e Linear polarizers θ=90° n1 Linear polarizers θ=0° n2 Plane polarized light No light Isoclines α=0 Extinction of all wavelengths for: =0 or =/2 α α α n.e=k. Yann Auffret Microscopic Properties

25. I. Lyotropic Lamellar Phases ω Addition of λ/4 waveplates: α(t)≈ω.t with ω>>1 P P A A Without λ/4 waveplates With λ/4 waveplates Yann Auffret Microscopic Properties Unpolarized white light source Microscope or wide lens camera Linear polarizer θ=0° λ/4 waveplate θ=45° sample λ/4 waveplate θ=-45° Linear Analyzer θ=90°

26. II. Shear Induced Structural Evolution Shear rate: Shear stress: Shear Viscosity: Yann Auffret Shear rheometry • Strain-controlled mode: • Constant applied angular velocity • Torque evolution • Stress controlled mode: • Constant applied torque • Angular displacement evolution Usual Shear Cells

27. III. Non-linear Viscoelastic Properties Constant apparent shear rate for: g>>a g=r.tan() gmin~a 40Pa 20Pa Invariant apparent steady shear rate with various surface roughnesses g=R2-R1 g>>a Yann Auffret Controlled Rheometry?

28. III. Non-linear Viscoelastic Properties Tw=0s Tw=9hours Inertial Coupling Analysis Yann Auffret Recovery Time Effects init 10 Applied Stress (Pa)‏ Tw 0.2