Effet Ouzo : Mélange, Coalescence, Répulsions

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1 Effet Ouzo : Mélange, Coalescence, Répulsions
Kevin Roger 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 Uniform hydrodynamic domains
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 Bad Mixing 10-2 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in good mixing conditions : opportunity to study the precipitation K. Roger*, C. Tang, R.K. Prud’homme and B. Cabane, unpublished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 Synchrotron X-ray beam
Suivi cinétique SAXS Synchrotron X-ray beam Fast-mixing chamber (5ms) Stop the flow Start acquisition Detector Acetone-filled Syringe (buffer) Water-filled syringe Polymer solution-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 Growth through coalescence
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 The polydispersity decreases with time !
Un chemin vers des populations étroites Distributions obtained through an original inversion procedure Method in : R.Botet & B.Cabane Journal of Applied Crystallography 2012 The polydispersity decreases with time !

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 Air bubbles are moving to the cathode (Quincke 1861)
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 ? |μ| 20 kT pH Des observations générales
Marinova et Al, Langmuir 1996 Surfactant-free conditions? OH- adsorption? Special water structuring? 20 kT |μ|

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