Cassie-Baxter to Wenzel state wetting transition: Scaling of the front velocity

摘要

We experimentally study the dynamics of water in the Cassie-Baxter state to Wenzel statetransition on surfaces decorated with assemblies of micrometer-size square pillars arranged on a squarelattice. 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 wettingfront velocity dependence on the geometry and material properties. We show that a decrease in gapsize as well as an increase in pillar height and intrinsic material hydrophobicity result in a lower frontvelocity. Scaling arguments based on balancing surface forces and viscous dissipation allow us to derivea relation with which we can rescale all experimentally measured front velocities, obtained for variouspattern geometries and materials, on one single curve.