osmotic pressure is the key
Transcription
osmotic pressure is the key
Cours de chimie séparative M3/D1-D2 Master CSMP ED 459 Session 2013-2014 : Osmotic pressure : Diving in the sea : take into account pressure versus depth ! Diving in nano-world: osmotic pressure is the key [email protected] 14/12/2013 Cours de chimie séparative Master CSMP ED 459 Session 2013-2014 : - - - Osmotic pressure : General meaning Historic approach : Jean Perrin Osmotic pressure in practical applications Osmotic presure to investigate LRI : EOS Jean-francois.dufrê[email protected] 7/12/2013 II P+ΔP I P Osmotic pressure : derivative of free energy vs volume Controlled humidity, membrane or capillary rise HR fixée H.R. = P/P0 = asolvant X X X Dispersion Solution sursaturée de sel (ou tonomètres…) π =− k.T .ln$&%asolvant ')( 0 Vsolvant dispersion membrane solvant capteur de P P = Patm + ms.g.h h P' = Patm Π = P-P’ = ρs.g.h réservoir solution Dessicating salt set : the poor man’s method The osmotic stress* method , even without membrane I II - réservoir *alias « pressostat » Parsegian, ….Brotons G. et al., Langmuir (2003)… Equation of state : EOS ( P, T; c) Van’t Hoff equation (1903) >> Van de Waals fluid π =1 ρ.k.T Carnahan-Starling dispersion of spheres ( φ= frac. Vol.) 2 3 π 1+φ +φ −φ = 3 ρ.k.T (1−φ ) Ideal situation: theta solvent Possible atmospheres ( Laplace>van’t Hoff) Mgh P = P0 .exp(1− ) NkbT Mgh Π = Π 0 .exp(1− ) NkbT Jean Perrin « Les atomes », 1908 Measuring macroscopic a-toms ( 330 nm) Jean Perrin « Les atomes », 1908 The colloidal atmosphere Jean Perrin « Les atomes », 1908 Equation of state of van der Waals gas Jean Perrin « Les atomes », 1908 Extension to charged colloids :Latex particles 0.4 µm % − V (r ) ( Π = ρ .kT(1 + ρ 2 ∫ ' e k T − 1* .4πr 2 .dr ) ' *) 0 & ∞ V. Reus et al. /Colloidal Colloids and crystals Surfaces A: :Physicochem. latex Eng. Aspects 151 (1999) 449–460 tion the osmotic of the A incrystals centimetersinduced of water asby a function of the salin V. ofReus et al.:pressure Fusion of sample colloidal monovalent an onstant volume fraction equal to 5.5%. Open squares represent samples with a liquid order and asymmetric salt: osmotic and USAXS (1999) with the Pois lline order. The full line an corresponds to pressure theoretical osmotic pressures calculated Colloidal crystals : latex V. Reus et al.: Fusion of colloidal crystals induced by monovalent an Hydroxymethylcellulose-based gels Cécile Bonnet_Gonnet et al. « Measurement of Forces between Hydroxy propyl cellulose Polymers: Temperature Favored Assembly and Salt Exclusion » (2001) Synthetic clays : Onsager mechanism M. Page et al: Osmotic pressure and phase boundary determination of multiphase systems by analytical ultracentrifugation (2008) Micelles are colloids % − V (r ) ( Π = ρ .kT(1 + ρ 2 ∫ ' e k T − 1* .4πr 2 .dr ) ' *) 0 & ∞ The structure of micelles and microemulsions », Y. Chevalier et al. 1991 Long Range Interactions In Nanoscale Science ; R G French , V A Parsegian et al. (2010) The devil is the contact pressure ! ! 109 Pascals and 0.03 nm3 > 0.2 nm > 0.15 nm2 means DG = 8kT=20 kJ (DH-TDS) Primary vs secondary hydration force ! Predicts osmotic pressure and phase limits ! Primary vs secondary hydration force F. Oosawa analytical simple expression (1954-1957) From equation of state to master equation Van’t Hoff = Van der Waals fluid / Jean Perrin -curvature, shape ??? Molecular, colloidal(meso), mechanical " ∂G % " ∂G % " ∂G % δU mech = Π = + + $ ' $ ' $ ' # ∂V &µ j # h.∂A &µ j # A.δ h &µ j ∂V