Issue
EPL
Volume 81, Number 6, March 2008
Article Number 66002
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/81/66002
Published online 20 February 2008
EPL, 81 (2008) 66002
DOI: 10.1209/0295-5075/81/66002

Multiple time scale dynamics in the breakdown of superhydrophobicity

C. Pirat1, M. Sbragaglia1, A. M. Peters2, B. M. Borkent1, R. G. H. Lammertink2, M. Wessling2 and D. Lohse1

1  Physics of Fluids, Department of Applied Physics, University of Twente P.O. Box 217, 7500 AE Enschede, The Netherlands
2  Membrane Technology Group, Department of Chemical Engineering, University of Twente P.O. Box 217, 7500 AE Enschede, The Netherlands


received 26 July 2007; accepted in final form 19 January 2008; published March 2008
published online 20 February 2008

Abstract
Drops deposited on rough and hydrophobic surfaces can stay suspended with gas pockets underneath the liquid, then showing very low hydrodynamic resistance. When this superhydrophobic state breaks down, the subsequent wetting process can show different dynamical properties. A suitable choice of the geometry can make the wetting front propagate in a stepwise manner leading to square-shaped wetted area: the front propagation is slow and the patterned surface fills by rows through a zipping mechanism. The multiple time scale scenario of this wetting process is experimentally characterized and compared to numerical simulations.

PACS
68.08.Bc - Wetting.
68.03.Cd - Surface tension and related phenomena.
68.08.De - Liquid-solid interface structure: measurements and simulations.

© EPLA 2008