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SANS at interfaces and in bulk systems under shear Henrich Frielinghaus JCNS c/o TUM, 85747 Garching.

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Presentation on theme: "SANS at interfaces and in bulk systems under shear Henrich Frielinghaus JCNS c/o TUM, 85747 Garching."— Presentation transcript:

1 SANS at interfaces and in bulk systems under shear Henrich Frielinghaus JCNS c/o TUM, 85747 Garching

2 Hydrogen Bonds Ionic // Coulomb Van Der Vaals Teflon / Flourinated Carbon Molecules Surfactants

3 Detergents Hair care Enhanced oil recovery Cosmetics Personal care Applications of Surfactants

4 CMC Macroscopic Volumes water

5

6 conewedgecylinder P = 0.. 1/3, 1/3.. 1/2, 1/2.. 1, 1 Packing Parameter

7 Symmetry: Entropy: Finite Length Finite Area Shape Curvature Undulations Undulations

8

9 L3L3 LαLα H1H1

10 Symmetry: Cubic, hexagonal, lamellar… Entropy: Distortions Soft MatterClassical Hard Matter Soft PotentialsCoulomb Potentials High EntropyLow Entropy Interactions Steric Repulsions Coulomb Interactions

11 Microemulsions Water: H 2 OOil: Decane Surfactant: C 10 E 4 Film WaterOil Micelles Stability !!!

12

13 1µm Bicontinuous Microemulsion

14 Larson

15 Free Energy R1R1 R2R2 c 1 = R 1 -1 c 2 = R 2 -1

16 γ -1 Phase Diagram f. Small Concentrations

17 Interactions

18 Oil Surfactant Water

19 Translational Entropy N: lattice sites k: species A N-k: species B

20 Summary: Microemulsions From Bulky Surfactant Molecules  Surfactant Film * Packing Parameter * Helfrich Energy Simple Shapes (diluted system) Liquid Crystalline Phases

21 Measurements

22 Optical Measurements Crossed Polarizers Anisotropic Domains Rheology

23 NMR - Microemulsion

24 Small Angle Scattering: Monochromator Collimation Incident Beam Sample Θ Detector Intensity

25 SAS PEO-PB PS-PI

26

27

28 Formfactors

29 TEM

30 Summary Measurements Optical NMR Rheology Relative Viscosities Frequency sweep Small Angle Scattering For many peaks: High accuracy For indistinguishable peaks: Esoteric TEM Many cuts needed isotropic / anisotropic quick and easy powerful (single crystals) further extension …

31 Scattering from polymeric systems Polymer Micelles Wormlike Micelles

32 PEP 10 -PEO 10 and PEP 22 -PEO 22 PEP 1 -PEO 1

33

34 PS in CS 2 water/isooctane/lecitin Wormlike Micelles or Polymer

35 Oil Production Aqueous Surfactant Systems are used for: Drilling Fluid Secondary/Tertiary Oil Production Fracturing Fluid

36 Simulations (M. Belushkin) Single order parameter: +1: Oil -1: Water 0: Surfactant Lamellar order decays !!!

37 The System The Cell Water: D 2 O, H 2 O (41.5%vol) Oil: Decane (41.5%vol) Surfactant: C 10 E 4 (17.0%vol) Temperature ca. 25°C Silicon Cd Glass with Boron Cd 0.5 mm 2 cm 15 cm 0.1° n

38 The Cell

39

40 GISANS: 2 nm < ζ // < 600 nm (large  y,  critical angle)  might be large... Reflect.: 1 µm < ζ // < 20 µm  Grazing incidence:

41 Evanescent Wave: the depth information

42 Measurements vs. Fits

43 Results from GISANS Lamellar: Peak Isotropic: perforated lam. + bicontinuous

44 n n

45 Microemulsion with Unsymmetric Polymer WATER

46 Shear Scans with SANS hexagonal

47 Comparison to Injected Microemulsion in GISANS Cell Perfect Alignment No Alingnment Lamellar Order Near Surface shear

48 Comparison to Injected Microemulsion in GISANS Cell shear Silicon

49 Summary Amphiphile Condensation – Self Assembly High Symmetry Interactions Concepts: * Aqueous Surfactant Systems * Microemulsions * (Polymeric Systems) not here * (Mesoscopic Particles) (Ianus) not here Actual research: Surfaces Mesoscopic Particles Surfactants + Polymers


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