Berlin 2008 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 14: Statistical physics II (general)
DY 14.5: Talk
Tuesday, February 26, 2008, 15:15–15:30, MA 004
Critical Adsorption and Critical Casimir Force at Geometrically Structured Substrates — •Matthias Tröndle1,2, Ludger Harnau1,2, and Siegfried Dietrich1,2 — 1Max-Planck-Institut für Metallforschung, Heisenbergstr. 3, 70569 Stuttgart — 2Universität Stuttgart, Institut für Theoretische und Angewandte Physik, Pfaffenwaldring 57, 70569 Stuttgart
We study the behavior of fluids close to geometrically structured substrates upon approaching a critical point at T=TC in their bulk phase diagram. The substrate surfaces are modeled by periodic arrays of wedges and ridges.
Guided by general scaling considerations we calculate, within the mean field approximation, the order parameter profiles of a fluid close to a single structured substrate for T>TC, T=TC, and T<TC. Universal amplitudes for a suitably defined excess adsorption are discussed.
Universal scaling functions for forces between geometrically structured substrates mediated by critical fluids are calculated within mean field theory. Normal forces between flat and structured substrates as well as lateral forces between two identically structured substrates are studied.