Simulation of Droplet Resting on Micro-structured Surface by Lattice Boltzmann Method

Three-dimensional liquid droplet resting on micro-structured pillar surface is simulated with lattice Boltzmann method incorporat- ing the Cahn-Hilliard equation. This is based on the two-phase model of Zheng et al. [14], combined with partial wetting boundary condition of Briant et al. [12]. Two Simulations are conducted with the same area fractions but different pillar heights, i.e. surface roughness, which is shown to have minor influence on the apparent contact angles at the Cassie state investigated. The predicted apparent contact angles are contrasted with measurements. Predictions show lower apparent contact angles and the deviations are around 10%. This might be due to the inadequate treatment of wetting boundary condition of the pillar surface, and this is deserved to be further studied.