Solvent mediated interactions between model colloids and interfaces: A microscopic approach

Abstract

We determine the solvent mediated contribution to the effective potentials for model colloidal or nano- particles dispersed in a binary solvent that exhibits fluid-fluid phase separation. Using a simple density functional theory we calculate the density profiles of both solvent species in the presence of the `colloids', which are treated as external potentials, and determine the solvent mediated (SM) potentials. Specifically, we calculate SM potentials between (i) two colloids, (ii) a colloid and a planar fluid-fluid interface, and (iii) a colloid and a planar wall with an adsorbed wetting film. We consider three different types of colloidal particles: colloid A which prefers the bulk solvent phase rich in species 2, colloid C which prefers the solvent phase rich in species 1, and `neutral' colloid B which has no strong preference for either phase, i.e. the free energies to insert the colloid into either of the coexisting bulk phases are almost equal. When a colloid which has a preference for one of the two solvent phases is inserted into the disfavored phase at statepoints close to coexistence a thick adsorbed `wetting' film of the preferred phase may form around the colloids. The presence of the adsorbed film has a profound influence on the form of the SM potentials.

17 Pages, 13 Figures. Accepted for publication in Journal of Chemical Physics

References in corpus (9)

• Grain Boundary Scars and Spherical Crystallography
• Effective capillary interaction of spherical particles at fluid interfaces
• Capillary bridging and long-range attractive forces in a mean-field approach
• Non-analytic curvature contributions to solvation free energies: influence of drying
• Solvent mediated interactions close to fluid-fluid phase separation: microscopic treatment of bridging in a soft core fluid
• Microscopic theory of solvent mediated long range forces: influence of wetting
• Pair correlation functions and phase separation in a two component point Yukawa fluid
• Structure of a liquid crystalline fluid around a macroparticle: Density functional theory study
• Interfacial and wetting properties of a binary point Yukawa fluid

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