Energy of interaction between solid surfaces and liquids

TL;DR

This paper refines the modeling of solid-liquid interactions by incorporating the entire fluid density profile into the surface energy calculation, extending classical models and including fluid mixtures.

Contribution

It introduces a more accurate surface energy representation that considers the full density profile and extends the model to fluid mixtures.

Findings

Enhanced surface energy model considering density profiles

Mean-field approximation for interaction potentials

Extension to fluid mixtures in contact with solids

Abstract

We consider the wetting transition on a planar surface in contact with a semi-infinite fluid. In the classical approach, the surface is assumed to be solid, and when interaction between solid and fluid is sufficiently short-range, the contribution of the fluid can be represented by a surface free energy with a density of the form Phi(rho_s), where rho_s is the limiting density of the fluid at the surface. In the present paper we propose a more precise representation of the surface energy that takes into account not only the value of rho_s but also the contribution from the whole density profile rho(z) of the fluid, where z is the coordinate normal to the surface. The specific value of the functional of rho_s at the surface is expressed in mean-field approximation through the potentials of intermolecular interaction and some other parameters of the fluid and the solid wall. An extension to the case of fluid mixtures in contact with a solid surface is proposed.