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Effet Ouzo : Mélange, Coalescence, Répulsions

Effet Ouzo : Mélange, Coalescence, Répulsions. Kevin Roger kevin.roger@espci.fr. Bernard Cabane, Robert Botet, Bob Prud ’ homme, Christina Tang. Le basculement de solvant en image. Diamètre (nm). PMMA + Acetone. Eau. Basculement de solvant, effet Ouzo et système modèle. Water.

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Effet Ouzo : Mélange, Coalescence, Répulsions

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  1. Effet Ouzo : Mélange, Coalescence, Répulsions Kevin Roger kevin.roger@espci.fr Bernard Cabane, Robert Botet, Bob Prud’homme, Christina Tang

  2. Le basculement de solvant en image Diamètre (nm) PMMA + Acetone Eau

  3. Basculement de solvant, effet Ouzo et système modèle Water Polymer solution Swollen PMMA nanoparticles PMMA Acetone

  4. Comprendre les mécanismes ANR Limouzine : Limite Ouzo, Interprétation, Estimation

  5. Hydrodynamique et Physico-chimie Uncoupling Polymer Solution Water Coupling

  6. Contrôler le mélange Homogeneous mixing : Uniform hydrodynamic domains Controlled mixing: Flux control to tune the size of the domains B.K. Johnson and R.K. Prud’homme and B. Cabane, AIChE journal, 2003

  7. Couplage ou découplage Polymer fraction 10-2 Bad Mixing 5.10-3 10-3 10-4 Good Mixing • Homogeneous mixing : no more Ouzo boundary • Uncoupling in good mixing conditions : opportunity to study the precipitation K. Roger*, C. Tang, R.K. Prud’homme and B. Cabane, unpublished

  8. Suivi cinétique SAXS Synchrotron X-ray beam Fast-mixing chamber (5ms) Stop the flow Start acquisition Detector Acetone-filled Syringe (buffer) Polymer solution-filled syringe Water-filled syringe Instrument ID02, ESRF, Grenoble K. Roger*, R. Botet and B. Cabane, Langmuir, 2013

  9. Courbes de diffusion de RX résolues en temps Porod limit Total surface time Oscillation Polydispersity Large distances Small distances

  10. Coalescence … lente Porod limit Total Surface Invariant Total Volume Logarithmic Growth Law Rmean = a.ln(t)+b Decreasing number of droplets Growth through coalescence

  11. Un chemin vers des populations étroites The polydispersity decreases with time ! Distributions obtained through an original inversion procedure Method in : R.Botet & B.Cabane Journal of Applied Crystallography 2012

  12. Contrôle par les charges de surface Adding surface charge (square dependence) OK for concentration dependence (log scale)

  13. Un outil sensible - - - - - - - - … … - - - - - - - - - - - - - - - Surface charge determines the size of the droplets Mean Radius decreases with the square of the surface charge Indirect method to quantify the surface charge

  14. Un vieux problème : la charge des systèmes purifiés Air bubbles are moving to the cathode (Quincke 1861) Oil droplets are moving to the cathode (Carruthers 1938)

  15. Des observations générales ? Marinova et Al, Langmuir1996 Surfactant-free conditions? OH- adsorption? Special water structuring? pH 20 kT |μ|

  16. Les impuretés sont partout… Adding fatty acids to 99.8%-pure C16 reproduces the behavior of 99%-pure C16 The purer the oil, the less stabilizer is available The stabilizer is in the oil and is not hydroxide ions. K. Roger* and B. Cabane, Angewandte Chemie 2012

  17. Et quand on s’en débarrasse… No colloidal metastability without charged end-groups PMMA-COOH particles PMMA-H particles K. Roger*, M. Eissa, A. Elaissari and B. Cabane, Langmuir 2013

  18. Comprendre l’importance du mélange Bad Mixing Polymer fraction 10-2 5.10-3 10-3 10-4 Good Mixing Dangerous area below the binodal : no repulsions

  19. Mélanges de polymères : l’effet Ouzo à plusieurs soluté

  20. Mélanges de polymères : l’effet Ouzo à plusieurs soluté Mixing PMMA-COOH (M=9900) and PMMA-H (M=9800) Fraction en PMMA-COOH : x Mixing PMMA-COOH (M=9900) and PMMA-H (M=25000) Fraction en PMMA-COOH : x

  21. Merci de votre attention Suite des festivités avec Robert Botet sète après-midi

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