Wetting in mixtures of colloids and excluded-volume polymers from density-functional theory.

We use a microscopic density-functional theory based on Wertheim's [J. Chem. Phys. 87, 7323 (1987)] first-order thermodynamic perturbation theory to study the wetting behavior of athermal mixtures of colloids and excluded-volume polymers. In opposition to the wetting behavior of the Asakura-Oosawa-Vrij [J. Chem. Phys. 22, 1255 (1954); Pure Appl. Chem. 48, 471 (1976)] model we find the polymer-rich phase to wet a hard wall. The wetting transition is of the first order and is accompanied by the prewetting transition. We do not find any hints for the layering transitions in the partial wetting regime. Our results resemble the wetting behavior in athermal polymer solutions. We point out that an accurate, monomer-resolved theory for colloid-polymer mixtures should incorporate the correct scaling behavior in the dilute polymer regime and an accurate description of the reference system.