Volcano-like hierarchical superhydrophobic surface synthesized via facile one-step secondary anodic oxidation

Superhydrophobic surface has been extensively applied in the field of self-cleaning and corrosion prevention, and the common preparation route of the superhydrophobic surface involves the construction of rough structure and modification with low-surface-energy regents in multistep process. Herein, a facile one-step method was proposed to fabricate the superhydrophobic surface with the simultaneous construction and modification of hierarchical microstructure and surface, the volcano-like anodic aluminium oxide (AAO)-based superhydrophobic surfaces with controllable roughness were synthesized via secondary anodic oxidation (SAO) process of AAO film in an organic-inorganic sol-gel system. During the SAO process, the perfluorooctyl triethoxysilane, which covalently bonded onto the surface, resulted in the inhomogeneous distribution of surface free energy and heterogeneous generation of volcano-like structure. The hydrophobic ability was enhanced by the rough hierarchical micro-/nanostructure with low surface energy, and the TiO2/PFOTS-AAO-15 exhibited the optimal water repellence with a WCA of similar to 154 degrees, self-cleaning performance and anticorrosion property in corrosive medium. This convenient method is anticipated to unlock various superhydrophobic surfaces on different substrates in the practical fields of self-cleaning and anticorrosion.