We study the formation and the shape of a liquid meniscus in a wedge with opening angle 2 ϕ which is exposed to a vapor phase. By applying a suitable effective interface model, at liquid-vapor coexistence and at a temperature T ϕ we find a filling transition at which the height of the meniscus becomes macroscopically large while the planar walls of the wedge far away from its center remain nonwet up to the wetting transition occurring at T w > T ϕ .Depending on the fluid and the substrate potential the filling transition can be either continuous or discontinuous. In the latter case it is accompanied by a owprefilling line extending into the vapor phase of the bulk phase diagram and describing a transition from a small to a large, but finite, meniscus height.The filling and the prefilling transitions correspond to nonanalyticities in the surface and line contributions to the free energy of the fluid, respectively.

Abstract. Mean field analysis of the effective interfacial Hamiltonian shows that with increasing temperature the adsorption on a periodically corrugated substrate can proceed in two steps: first, there is the filling transition in which the depressions of the substrate become partially or completely filled; then there is the wetting transition at which the substrate as a whole becomes covered with a macroscopically thick wetting layer. The actual order and location of both transitions are related to the wetting properties of the corresponding planar substrate and to the form of corrugation. Certain morphological properties of the liquid-vapor interface in the case of a saw-like corrugated substrate are discussed analytically.

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