Roughness-induced superhydrophobicity: a way to design non-adhesive surfaces

Abstract

Non-adhesive and water-repellent surfaces are required for many tribological applications.Roughness-induced superhydrophobicity has been suggested as a way to reduce adhesionand stiction. In this paper, the theory of roughness-induced superhydrophobicity ispresented. Wetting is studied as a multiscale process involving the macroscale (waterdroplet size), microscale (surface texture size), and nanoscale (molecular size). We studyfundamental physical mechanisms of wetting, including the transition betweenvarious wetting regimes, contact angle and contact angle hysteresis. The effect ofsurface roughness upon wetting and capillary adhesion force is discussed. Practicalrecommendations for the design of superhydrophobic surfaces are formulated.