Superwettable bulk Janus materials with mechanical robustness and underwater self-cleaning action

Janus materials exhibiting superwettability, unique structure, and fascinating properties have emerged as important candidates for solving the practical problems encountered in various fields. However, practical applications of such surfaces are limited due to their inability to repel oil in air and poor mechanical robustness. In this study, we developed a new concept of creating a bulk Janus material (BJM) that used porous skeleton structure to lock-in the nanocomposite filler. Compared to the Janus materials with characteristics similar to those of lotus leaf, the BJM exhibits in-air superamphiphobicity on one side and underwater superoleophobicity on the other side. Surprisingly, the BJM surfaces maintain their super-repellent nature toward liquids after finger-wipe, knife-scratch, sand impact, tape-peeling, and even 100 abrasion cycles with sandpaper. Moreover, these developed BJMs can be applied to underwater oil transportation channels, and they sustain high-efficient self-cleaning performance even after exposure to harsh environments. Undoubtedly, these materials should find potential usage in marine oil transportation pipelines.