Dual hierarchical biomimic superhydrophobic surface with three energy states

Abstract

A low hysteresis surface prepared by two-length-scaled hierarchical textures to mimic the Lotus effect is proposed. The fabricated textures incorporate self-masked nanorods on microextrusions. A high static contact angle (160°) and low hysteresis (∼2.7°) are obtained and comparable to the surface properties of a natural lotus leaf. The stability of hydrophobicity is described with respect to three energy states (nonwetting, microwetting, and nanowetting) based on dynamic contact angle analysis by droplet impinging onto the surface. The estimated texture-induced energy barrier based on the principle of energy conservation is in good agreement to those estimated from Laplace’s law.