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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 30: Poster: Focus: Wetting on smooth and rough surfaces: From spreading to superhydrophobicity

CPP 30.12: Poster

Wednesday, March 13, 2013, 16:30–18:30, Poster C

Universal Phase Diagram for Wetting on Mesoscale Roughness — •Stephan Herminghaus — MPI für Dynamik und Selbstorganisation

The wetting properties of solid substrates with mesoscale (between van der Waals tails and the capillary length) random roughness are considered as a function of the microscopic contact angle of the wetting liquid and its partial pressure in the surrounding gas phase. It is shown that the well-known transition occurring at Wenzel's angle is accompanied by a transition line at which a jump in the adsorbed liquid volume occurs. This should be present generally on surfaces bearing homogeneous, isotropic random roughness. While a similar abrupt filling transition has been reported before for certain idealized groove or trough geometries, it is identified here as a universal phenomenon. Its location can be analytically calculated under certain (rather mild) conditions.