Construction of Robust Hierarchical Micro-nanostructure by Laser Irradiation and Hydrothermal Treatment on Titanium Alloy for Superhydrophobic and Slippery Surfaces

Although a large number of bionic superhydrophobic surfaces have been reported in recent years, their poor robustness remains to be improved. Herein, we present a method to fabricate a hierarchical micro-nanostructure on Ti6Al4V with excellent robustness by combining laser direct writing technology and hydrothermal treatment. Microscale pore array pattern with hard oxide layer was generated by laser irradiation, which provided protection for the nanowires later grown in situ by hydrothermal treatment. After low surface energy molecular modification, the composite surface exhibited outstanding wetting properties with a contact angle of 165.2 degrees and a roll-off angle less than 1 degrees. We focused on the mechanical and chemical stability of the as-prepared superhydrophobic surface (SHS), and the performance tests included water jet impact, cyclic friction, solution immersion, heat treatment and UV irradiation. Additionally, the SHS was transformed into slippery liquid-infused porous surface (SLIPS) by lubricant injection, which expends the applications of the hierarchical micro-nanostructure surface. Considering the loss degree and the self-repairing performance of the lubricants with different viscosities, we can conclude that the lubricant with a viscosity of 350 mPa center dot s matches the SHS substrate best. The constructed SHS and SLIPS show remarkable robustness and versatility and may be applied in various fields.

Automated summary

This article introduces a method to fabricate a hierarchical micro-nanostructure on Ti6Al4V with excellent robustness by combining laser direct writing technology and hydrothermal treatment. The composite surface exhibits outstanding wetting properties and passes multiple performance tests, such as water jet impact, cyclic friction, solution immersion, heat treatment, and UV irradiation. Additionally, the superhydrophobic surface can be transformed into slippery liquid-infused porous surface for extended applications.