[摘要]：We have fabricated and characterized a novel superhydrophobic system, a meshlike porous superhydrophobic membrane with solid area fraction Phi(s), which can maintain intimate contact with outside air and water reservoirs simultaneously. Oscillatory hydrodynamic measurements on porous superhydrophobic membranes as a function of Phi(s) reveal surprising effects. The hydrodynamic mass oscillating in phase with the membranes stays constant for 0.9 less than or similar to Phi(s) <= 1, but drops precipitously for Phi(s) < 0.9. The viscous friction shows a similar drop after a slow initial decrease proportional to Phi(s). We attribute these effects to the percolation of a stable Knudsen layer of air at the interface.
