Fluid Dynamics Seminar

Monday, Apr. 25, 2011, 4:00 PM
Cullimore Hall, Room 611
New Jersey Institute of Technology


Wetting Transition, Drop Impact, and Micro-Flows upon Hydrophobic Microstructures

Peichun Amy Tsai


Dept. Mechanical & Aerospace Engineering, Princeton University



Hydrophobic microstructures, which may display superhydrophobicity, shed light on applications in coating, drying, and microfluidics. In this talk, three examples of wetting effects on regular and irregular water-repelling surfaces are presented, namely (i) an evaporation-triggered wetting transition at which a gently deposited water drop on the microstructures jumps from the heterogenous (Cassie-Baxter) to the homogenous (Wenzel) wetting state, (ii) drop impact on superhydrophobic substrates, with an emphasis on the influences of nano-roughness, microstructure patterns, and air pressure, and (iii) laminar micro-flows over hydrophobic micro-grooves, with which effective slippage can be achieved. We learn that the intervening air layer plays an important role in these three scenarios.