Analysis of Gas Diffusion-Induced Cassie to Wenzel State Transition on a Structured Surface

Abstract

We provide an approximate and one-dimensional solution for transient diffusion of gas between parallel ridges into a degassed and quiescent liquid suspended in the Cassie state above a parallel-ridge type structured surface. At time equal to zero, the liquid and gas are at the same pressure; therefore, the meniscus formed between ridges is flat. The analysis provides the transient gas concentration field in the liquid. It also computes the times when the triple contact line begins to move down the ridges and that when the meniscus contacts the bottom substrate compromising the Cassie state.