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O: Oberflächenphysik

O 4: Oxide und Isolatoren / Phasenüberg
änge

O 4.1: Vortrag

Montag, 23. März 1998, 11:15–11:30, H37

The filling transition for a wedge — •K. Rejmer, S. Dietrich, and M. Napiórkowski — Bergische Univ. Wuppertal, Fachbereich Physik, Postfach 100127, D-42097 Wuppertal.

We study the formation and the shape of the liquid meniscus in a wedge with opening angle 2 ϕ which is exposed to the vapour phase. By applying a suitable effective interface model, at liquid-vapor coexistence and at temperature T_ϕ we find a filling transition at which the height of the meniscus becomes macroscopically large but the planar walls of the wedge far away from the 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 prefilling line extending into the vapour phase of the bulk phase diagram and describing transition from a small to a large, but finite, meniscus height. The filling and the prefilling transitions correspond to singularities in the line contribution to the free-energy of the fluid.