LAUSR

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.