Entropically driven ordering in a binary colloidal suspension near a planar wall - art. no. 012401

The local ordering of a binary hard-sphere mixture with a size ratio 1:10 n ear a planar wall is investigated by means of integral equation theory. We find that when the bulk volume fraction of the smaller particles is greater than 15%. the larger particles (at a bulk volume fraction of 1% and higher ) become highly localized on the wall surface, forming a quasi-two-dimensio nal surface-localized monolayer. Our results are discussed and compared aga inst computer simulation data with an effective one-component Hamiltonian t hat is based on sphere-sphere and sphere-wall depletion potentials.