  We report a numerical study of equilibrium phase-diagrams and interfacial
properties of bulk and confined colloid-polymer mixtures using grand canonical
Monte Carlo simulations. Colloidal particles are treated as hard spheres, while
the polymer chains are described as soft repulsive spheres. The
polymer-polymer, colloid-polymer, and wall-polymer interactions are described
by density-dependent potentials derived by Bolhuis and Louis [Macromolecules,
35 (2002), p.1860]. We compared our results with those of the
Asakura-Oosawa-Vrij model, that treats the polymers as ideal particles. We find
that the number of polymers needed to drive the demixing transition is larger
for the interacting polymers, and that the gas-liquid interfacial tension is
smaller. When the system is confined between two parallel hard plates, we find
capillary condensation. Compared with the AOV model, we find that the excluded
volume interactions between the polymers suppress capillary condensation. In
order to induce capillary condensation, smaller undersaturations and smaller
plate separations are needed in comparison with ideal polymers.
