Bioinspired multifunctional hetero-hierarchical micro/nanostructure tetragonal array with self-cleaning, anticorrosion, and concentrators for the SERS detection.

Heterohierarchical micro/nanostructure tetragonal array consisted of engineering materials of microprotrusion-like Cu and secondary nanostructured dendrite Ag have been fabricated via a primary cell-induced deposition and a facile galvanic displacement reaction combined with photolithography technique on Cu foil. Confined by the circle microwell tetragonal array of the photoresist template, regular microprotrusion-like Cu with the tunable size of diameter can be easily deposited on the surface of Cu foil. Then, the secondary dendritic Ag nanostructures in situ grow on the surface of microprotrusion via a galvanic displacement reaction, leading to the formation of heterohierarchical micro/nanostructure tetragonal array, which is similar to the surface microstructure of the lotus leaf. Inspired by this novel surface structure of imitating lotus leaf, its wettability has been systematically investigated. The results indicate that the fabricated heterohierarchical micro/nanostructure regular array after the surface fluoration presents a remarkable superhydrophobic performance. Initiated from its superhydrophobicity, an excellent self-cleaning property has also been demonstrated. In addition, the durability of the superhydrophobic surfaces is examined in the wide pH range of corrosive liquids. Notably, the fabricated superhydrophobic surface can be potentially used as concentrators, which presents a great perspective in the field of analysis through employing the SERS detection as an example.