Issue
EPL
Volume 87, Number 3, August 2009
Article Number 36003
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/87/36003
Published online 27 August 2009
EPL, 87 (2009) 36003
DOI: 10.1209/0295-5075/87/36003

Drops onto gradients of texture

M. Reyssat1, F. Pardo2 and D. Quéré1

1   Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, ESPCI - 10 rue Vauquelin, 75005 Paris, France, EU
2   Laboratoire de Photonique et Nanostructures, UPR 20 du CNRS - Route de Nozay, 91460 Marcoussis, France, EU

david.quere@espci.fr

received 20 May 2009; accepted in final form 20 July 2009; published August 2009
published online 27 August 2009

Abstract
Hydrophobic microtextures on solids provide water repellency: drops hardly stick on these materials and bounce off after impacts. Here we achieved solids decorated with a texture of variable density. Impacting water drops were observed to bounce off obliquely, demonstrating a transfer of vertical momentum in the horizontal direction, after rebound. This allows us to understand why vibrated drops move on such surface: an asymmetric dewetting takes place for each cycle of the vibration, which leads to an incremental drift of the liquid towards regions of high texture density.

PACS
68.08.Bc - Wetting.
68.03.Cd - Surface tension and related phenomena.
85.40.Hp - Lithography, masks and pattern transfer.

© EPLA 2009