Fluid handling device with directionally-biased wetting surface

摘要

A fluid handling device with an anisotropic wetting surface including a substrate with a multiplicity of asymmetric substantially uniformly shaped asperities thereon. Each asperity has a first asperity rise angle and a second asperity rise angle relative to the substrate. The asperities are structured to present a desired retentive force ratio (f1/f2) greater or less than unity caused by asymmetry between the first asperity rise angle and the second asperity rise angle according to the formula: f3/f2=sin(ω3+½&Dgr;&thetas;0)/sin(ω2+½&Dgr;&thetas;0).