Dresden 2011 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 44: Micro- and Nanofluidics I

CPP 44.6: Talk

Thursday, March 17, 2011, 15:15–15:30, ZEU 160

Electrical switching of wetting states on superhydrophobic surfaces: a route towards reversible Cassie-to-Wenzel transitions — Gor Manukyan, Oh Jung Min, van den Ende Dirk, Lammertink Rob, and •Mugele Frieder — University of Twente, MESA institute, Enschede, The Netherlands

We demonstrate that the equilibrium shape of the composite interface between superhydrophobic surfaces and drops in the Cassie state under electrowetting is determined by the balance of the Maxwell stress and the Laplace pressure. Energy barriers due to pinning of contact lines at the pillar edges control the transition from Cassie to the Wenzel state. Barriers due to the narrow gap between adjacent pillars control the lateral propagation of the Wenzel state. Suitable engineering of surface and electrode geometries allows for reversible local switching between the two wetting states.