Biomimetic design of surface architecture with simultaneously enhanced hydrophobicity and mechanical stability

Abstract

The practical applicability of artificial superhydrophobic surfaces has been limited by their poor mechanical stabilities. In this study, the delicate interplay between surface hydrophobicity and mechanical stability has been investigated quantitatively through a combined thermodynamic and micromechanical methodology. Based on the thermodynamic analysis, it was found that stable composite/superhydrophobic wetting states could be obtained on the micro/nano textured surface with low aspect ratio micropillars. Notably, the hydrophobicity of the textured surface could be enhanced by decreasing the microscale ratio of pillar width and spacing or increasing the nanoscale ratio of base spacing and radius. Concurrently, the critical forces for Euler bucking instability of superhydrophobic surface textures were numerically calculated. The results showed that the structural stability of superhydrophobic surface could be substantially increased by introducing nano-scale roughness or reducing the aspect ratio of micropillar. Finally, the design strategy was utilized to fabricate superhydrophobic surface which demonstrated sustained superhydrophobicity and mechanical stability.