Wetting and evaporation phenomena of water droplets on textured surfaces

Abstract

When water droplets are placed on a surface, the contact angle depends on the surface conditions, and the subsequent evaporation of the droplets depends on the wetting phenomena. In this study, we investigated the wetting and evaporation of droplets of deionized water from surfaces with various intrinsic contact angles and surface morphologies (θ0=34°, 58° and 109°, 1.00<fW<2.00, 0.02<fC–B<1.00). For each droplet, the apparent contact angle and radius of the contact line were measured, and the wetting state was visualized with synchrotron X-ray radiography. Comparing between the experimental data and the results of a number of wetting models, the models were experimentally validated. On the basis of the wetting phenomena, the evaporation rate depending on the surface condition is clarified in the experimental ranges.