Fabrication of biomimetic anisotropic super-hydrophobic surface with rice leaf-like structures by femtosecond laser

Abstract

It was found that the anisotropic hydrophobicity of rice leaves was caused by the multi-level grooves and tiny papillary microstructures on their surface. Inspired by rice leaves, a rice leaf-like anisotropic super-hydrophobic aluminum surface was obtained by femtosecond laser raster scanning. The surface structure, chemical composition, contact angle and sliding angle of the structured aluminum surface have been investigated in detail. The results show that structured surface appears super-hydrophobic with sliding anisotropy. The contact angle reaches 153° for 5 μl water droplet. The sliding angle is about 9° along the groove direction and about 34° perpendicular to the groove direction for 10 μl water droplet. • The surface structures of the rice leaves were investigated and the mechanism of anisotropic hydrophobicity of rice leaves was revealed. • It achieves the processing of hierarchical grooves and tiny papillary microstructures in “one step”. • The dominant mechanism for the directional wetting was discussed.