Bouncing or sticky droplets: Impalement transitions on superhydrophobic micropatterned surfacesD. Bartolo1, F. Bouamrirene1, É. Verneuil2, A. Buguin2, P. Silberzan2 and S. Moulinet1
1 Laboratoire de Physique Statistique de l'ENS, CNRS, UMR 8550 associée aux Universités Paris 6 et Paris 7 - 24 rue Lhomond, 75231 Paris Cédex 05, France
2 Laboratoire de Physico-Chimie Curie, Institut Curie, CNRS, UMR 168 26 rue d'Ulm, 75248 Paris Cédex, France
received 18 November 2005; accepted in final form 14 February 2006
published online 15 March 2006
When a liquid drop impinges a hydrophobic rough surface it can either bounce off the surface (fakir droplets) or be impaled and strongly stuck on it (Wenzel droplets). The analysis of drop impact and quasi-static "loading" experiments on model microfabricated surfaces allows to clearly identify the forces hindering the impalement transitions. A simple semi-quantitative model is proposed to account for the observed relation between the surface topography and the robustness of fakir non-wetting states. Motivated by potential applications in microfluidics and in the fabrication of self-cleaning surfaces, we finally propose some guidelines to design robust superhydrophobic surfaces.
68.08.Bc - Wetting.
68.03.Cd - Surface tension and related phenomena.
47.55.D- - Drops and bubbles.
© EDP Sciences 2006