Evaporation and wetting behavior of water on the laser-textured silicon substrate

Abstract

It is important to elucidate the impact of surface micromorphology on the evaporation mechanism and behavior to design rational micromorphologies for enhancing/regulating evaporation. In this study, we investigated the wetting and evaporation behaviors of water droplets on monocrystalline silicon surfaces with concentric circular textures etched using a laser engraving system at varying spacing intervals. Only when the texture spacing overlapped did it exhibit a significantly increased apparent surface energy and evaporation rate. The droplet volume decreased consistently at a constant evaporation rate at different temperatures, and the process involved two stages: constant contact radius (CCR) and constant contact angle (CCA). Laser etching increases the thickness of the oxide film from 10 to 377 nm, resulting in enhanced hydrophilicity. For millimeter-sized droplets, microscopic capillary phenomena in the vicinity of the triple line dominated the evaporation behavior rather than liquid/gas interface evaporation.