Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: Wetting, Microfluidics and Confined Liquids I (joint session CPP/DY)
CPP 40.1: Hauptvortrag
Mittwoch, 14. März 2018, 09:30–10:00, C 264
Slippage over superhydrophobic surfaces: fundamentals and local phenomena — •Clarissa Schönecker1,2, David Schäffel2, Kaloian Koynov2, Doris Vollmer2, and Hans-Jürgen Butt2 — 1Lehrstuhl für Mikrofluidmechanik, TU Kaiserslautern — 2Max-Planck-Institut für Polymerforschung, Mainz
Superhydrophobic surfaces can provide a significant slip to a fluid flowing over the surface, making them attractive for the development of functional coatings. Although the global behaviour of flow past such surfaces has been widely investigated, understanding the local fundamentals that lead to slippage is still lacking. We studied in detail the local slip length and local flow field for water in the Cassie state on a structured superhydrophobic surface. Using fluorescence correlation spectroscopy, we revealed that the local slip length of a superhydrophobic surface is finite, non-constant and anisotropic. Furthermore, it can be strongly influenced by the presence of surface active substances. All these properties are in accordance with and can be explained by a theoretical model of the local hydrodynamics close to the surface. The study shows the effect of surface properties, like the surface geometry or interfacial forces.