Effet Ouzo : Mlange, Coalescence, RpulsionsKevin Roger [email protected]
Bernard Cabane, Robert Botet, Bob Prudhomme, Christina Tang
PMMA + AcetoneEauLe basculement de solvant en image
WaterPolymer solutionAcetonePMMASwollen PMMA nanoparticlesBasculement de solvant, effet Ouzo et systme modle
Comprendre les mcanismes ANR Limouzine : Limite Ouzo, Interprtation, Estimation
Hydrodynamique et Physico-chimieWaterPolymerSolutionUncouplingCoupling
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
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
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
Small distancesLarge distancesOscillationPorod limittimeTotal surfacePolydispersityCourbes de diffusion de RX rsolues en temps
Logarithmic Growth LawRmean = a.ln(t)+bPorod limit Total SurfaceInvariantTotal VolumeDecreasing number of dropletsGrowth through coalescenceCoalescence lente
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
Adding surface charge (square dependence)OK for concentration dependence (log scale)Contrle par les charges de surface
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
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)
?|| Marinova et Al, Langmuir 199620 kTDes observations gnralesSurfactant-free conditions?OH- adsorption? Special water structuring?
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
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
Good MixingBad MixingComprendre limportance du mlangeDangerous area below the binodal : no repulsions
Mlanges de polymres : leffet Ouzo plusieurs solut
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
Merci de votre attentionSuite des festivits avec Robert Botet ste aprs-midi
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