Switchable Wettability of Silicon Micro-Nano Structures Surface Produced by Femtosecond Laser

Abstract

Silicon micro-nanostructures were directly produced by femtosecond laser in air. By varying the laser power, we can tune the surface morphology, the wetting property. As-prepared silicon micro-nanostructures show superhydrophilicity, but with removal of native SiOx, superhydrophobicity is observed without surface modification. And a reversible switch between superhydrophilicity and superhydrophobicity can be realized by immersing samples in hydrofluoric acid and hydrogen peroxide, respectively, for many times.