Prewetting at a liquid mixture–solid interface: A comparison of Monte Carlo simulations with mean field density functional theory

Abstract

We present a comparison of the predictions of mean field density functional theory with recent Monte Carlo simulation results for adsorption from a binary liquid mixture in contact with a wall. The symmetric liquid mixture under consideration exhibits liquid–liquid immiscibility with an upper critical solution temperature and the simulation results are consistent with a first order wetting transition with an accompanying prewetting line. The density functional theory gives quite good predictions of the wetting phase diagram for the system when the effect of errors in the bulk thermodynamic properties is removed. However, the composition distribution and adsorption isotherms show significant deviations reflecting the inability of the mean field theory to account correctly for the composition correlations in the system.