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

• Superhydrophobic surface is prepared by secondary anodic oxidation (SAO) process. • The SAO process simultaneously constructs and modifies the rough structure. • Inhomogeneous surface energy leads to the formation of volcano-like structure. • Hydrophobic ability is enhanced significantly by the modified micro-/nanostructure. • Excellent water repellence and self-cleaning ability are obtained. 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 TiO 2 /PFOTS-AAO-15 exhibited the optimal water repellence with a WCA of ~154°, 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. [ABSTRACT FROM AUTHOR]