Effet Ouzo : Mélange, Coalescence, Répulsions
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Transcript of Effet Ouzo : Mélange, Coalescence, Répulsions
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Effet Ouzo : Mlange, Coalescence, RpulsionsKevin Roger [email protected]
Bernard Cabane, Robert Botet, Bob Prudhomme, Christina Tang
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PMMA + AcetoneEauLe basculement de solvant en image
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WaterPolymer solutionAcetonePMMASwollen PMMA nanoparticlesBasculement de solvant, effet Ouzo et systme modle
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Comprendre les mcanismes ANR Limouzine : Limite Ouzo, Interprtation, Estimation
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Hydrodynamique et Physico-chimieWaterPolymerSolutionUncouplingCoupling
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Contrler le mlangeB.K. Johnson and R.K. Prudhomme and B. Cabane, AIChE journal, 2003Homogeneous mixing :Uniform hydrodynamic domains
Controlled mixing:Flux control to tune the size of the domains
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Good MixingBad MixingPolymer fraction10-25.10-310-310-4K. Roger*, C. Tang, R.K. Prudhomme and B. Cabane, unpublishedCouplage ou dcouplageHomogeneous mixing : no more Ouzo boundaryUncoupling in good mixing conditions : opportunity to study the precipitation
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Water-filledsyringePolymer solution-filledsyringeAcetone-filledSyringe(buffer)Synchrotron X-ray beamFast-mixing chamber (5ms)DetectorStop the flowStart acquisitionInstrument ID02, ESRF, GrenobleSuivi cintique SAXSK. Roger*, R. Botet and B. Cabane, Langmuir, 2013
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Small distancesLarge distancesOscillationPorod limittimeTotal surfacePolydispersityCourbes de diffusion de RX rsolues en temps
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Logarithmic Growth LawRmean = a.ln(t)+bPorod limit Total SurfaceInvariantTotal VolumeDecreasing number of dropletsGrowth through coalescenceCoalescence lente
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Distributions obtained through an original inversion procedureMethod in : R.Botet & B.Cabane Journal of Applied Crystallography 2012
The polydispersity decreases with time !Un chemin vers des populations troites
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Adding surface charge (square dependence)OK for concentration dependence (log scale)Contrle par les charges de surface
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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
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Un vieux problme : la charge des systmes purifisAir bubbles are moving to the cathode (Quincke 1861)Oil droplets are moving to the cathode(Carruthers 1938)
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?|| Marinova et Al, Langmuir 199620 kTDes observations gnralesSurfactant-free conditions?OH- adsorption? Special water structuring?
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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 C16Les impurets sont partoutK. Roger* and B. Cabane, Angewandte Chemie 2012
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K. Roger*, M. Eissa, A. Elaissari and B. Cabane, Langmuir 2013 Et quand on sen dbarrassePMMA-COOH particlesPMMA-H particlesNo colloidal metastability without charged end-groups
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Good MixingBad MixingComprendre limportance du mlangeDangerous area below the binodal : no repulsions
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Mlanges de polymres : leffet Ouzo plusieurs solut
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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
Mlanges de polymres : leffet Ouzo plusieurs solut
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Merci de votre attentionSuite des festivits avec Robert Botet ste aprs-midi