Binary associating fluid mixtures against a hard wall: density functional theory and simulation

We present an extension of our perturbation density functional (DF) theory [SEGURA, C. J., CHAPMAN,W.G. and SHUKLA, K.P., 1997, Molec. Phys., 90, 759] , which applies the weighting from Tarazona's hard sphere density functiona l theory to Wertheim's bulk first-order perturbation theory, to form a pert urbation density functional theory for binary associating hard sphere fluid mixtures. Monte Carlo simulation results of a binary mixture of equal-size d hard spheres with one component having four associating sites placed in t he Bol [1982, Molec. Phys., 45, 605] fashion are presented to compare with the theory. Comparison of theory and molecular simulation for the separatio n factor, component density profiles and fraction of monomers (associating component) show good agreement. Good to excellent accuracy are obtained for the densities and temperatures studied.