Effect of Photoresist Biomimetic Surface Roughness on Droplet Evaporation Dynamics

Control of the wetting properties of biomimetic functional surfaces is a desired functionality in many applications. In this paper, the photoresist SU-8 was used as fabrication material. A silicon wafer was used as a substrate to prepare a biomimetic surface with different surface roughness and micro-pillars arranged in array morphology. The evaporation dynamics and interfacial heat transfer processes of deionised water droplets on the bioinspired microstructure surface were experimentally studied. The study not only proves the feasibility of preparing hydrophilic biomimetic functional surfaces directly through photoresist materials and photolithography technology but also shows that by adjusting the structural parameters and arrangement of the surface micro-pillar structure, the wettability of the biomimetic surface can be significantly linearly regulated, thereby effectively affecting the heat and mass transfer process at the droplet liquid-vapour interface. Analysis of the results shows that by controlling the biomimetic surface microstructure, the wettability can be enhanced by about 22% at most, the uniformity of the temperature distribution at the liquid-vapour interface can be improved by about 34%, and the average evaporation rate can be increased by about 28%. This study aims to provide some guidance for the research on bionic surface design based on photoresist materials.