Effect of processing environment on the wettability behavior of laser-processed titanium

The wettability properties of two types of titanium surfaces structured by femtosecond laser are studied. Samples that are textured in air, demonstrated superhydrophilic properties immediately after laser structuring. In contrast, just prepared samples, which are processed in vacuum, show an increase in the water contact angle compared to the unprocessed Ti. Since the surface morphology of both samples was similar, the observed superhydrophilic behavior of the samples prepared in air is attributed to the partial oxidation of Ti surface during laser texturing. High temperature post-annealing of the samples that were laser-structured in vacuum completely oxidized the Ti surface. This in turn led to the formation of a permanent hydrophilic surface that could not be changed even after storing in vacuum or ambient atmosphere for a long time.

Automated summary

This study investigates the wettability properties of two types of titanium surfaces structured by femtosecond laser. It is found that samples textured in air show superhydrophilic properties, while samples processed in vacuum exhibit an increase in water contact angle. The observed difference can be attributed to the partial oxidation of the titanium surface during laser structuring in air. High temperature annealing of vacuum-processed samples results in complete oxidation of the titanium surface, leading to the formation of a permanent hydrophilic surface.