Controllable wettability of metallic surfaces via micro-nano structure fabricated by femtosecond laser

Micro-pits array structure, micro-gratings structure covered with finer nanostructures were generated on titanium surfaces using femtosecond laser pulse. The wetting behavior of the two types of surface structures were studied. Micropits array structure with a size of dozens of microns exhibits hydrophilic properties, and the hydrophilicity increased with increasing the number of laser pulses. Micro-gratings structure covered with finer nanostructures exhibits hydrophobic properties, and the hydrophobicity increased with decreasing the laser energy density. The results demonstrated that wettability of metallic surface can be facilely controlled by adjusting the femtosecond laser processing parameters. The formation processes of the two types of surface microstructures as well as the underlying mechanisms for their special wettability are also discussed. This research might provide a facile controllable strategy to realize special wettability for metal or other solid surfaces, even expand the functions and applications of metals.