Wetting in thebinary Gaussian core model

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Using a simple mean-field density functional approach weinvestigate the adsorption of a binary fluid mixture ofrepulsive Gaussian core particles at a repulsive planar wall.For certain choices of wall-fluid potential we find afirst-order wetting transition, and the accompanying pre-wettingline, whereby the fluid phase rich in the larger speciescompletely wets the interface between the wall and the fluidphase rich in the smaller species. We show that in the completewetting regime the film thickness diverges as l~-l0ln (x-xcoex), where (x-xcoex) is the deviation inconcentration x of the smaller species from the bulk binodal,for all the (short-ranged) wall potentials that we have consideredbut the amplitude l0 depends on the precise details of thesepotentials.