https://doi.org/10.1140/epje/i2009-10489-3
Regular Article
Cassie-Baxter to Wenzel state wetting transition: Scaling of the front velocity
1
Membrane Technology Group, Faculty of Science and Technology, Mesa+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands
2
Physics of Fluids, Faculty of Science and Technology, Mesa+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands
3
Laboratoire de Physique de la Matière Condensée et Nanostructures, Université de Lyon, Univ. Lyon I, CNRS, UMR 5586, 69622, Villeurbanne, France
4
Department of Physics, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy
5
Impact, Institute on Mechanics, Processes and Control Twente, University of Twente, P.O. Box 217, 7500, AE Enschede, The Netherlands
* e-mail: r.g.h.lammertink@utwente.nl
Received:
6
April
2009
Accepted:
8
July
2009
Published online:
9
August
2009
We experimentally study the dynamics of water in the Cassie-Baxter state to Wenzel state transition on surfaces decorated with assemblies of micrometer-size square pillars arranged on a square lattice. The transition on the micro-patterned superhydrophobic polymer surfaces is followed with a high-speed camera. Detailed analysis of the movement of the liquid during this transition reveals the wetting front velocity dependence on the geometry and material properties. We show that a decrease in gap size as well as an increase in pillar height and intrinsic material hydrophobicity result in a lower front velocity. Scaling arguments based on balancing surface forces and viscous dissipation allow us to derive a relation with which we can rescale all experimentally measured front velocities, obtained for various pattern geometries and materials, on one single curve.
PACS: 68.03.Cd Surface tension and related phenomena – / 68.08.Bc Wetting – / 68.08.De Liquid-solid interface structure: measurements and simulations –
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2009