Modeling of Wetting in Restricted Geometries

This review discusses Monte Carlo simulations of simple models for fluids and binary mixtures (lattice gas, lattice models for binary polymer blends, Asakura-Oosawa model of colloid-polymer mixtures) in confined geometries. The geometries considered are thin films confined by either symmetric or competing walls, as well as wedges and pyramid-shaped cones, including “closed” geometries such as double wedges and bipyramids. Testing of theoretical concepts on the phase behavior in these geometries is emphasized: There is a delicate interplay between wetting phenomena and phase separation into vapor and liquid (or two fluids of different composition, respectively). Capillary condensation phenomena occur in thin films with symmetric walls, and interface localization transitions occur in cases with competing walls. Concepts on wedge filling and cone filling are also examined.