Laser-induced hydrophobicity on Ti-6Al-4V surface

Topographic and wetting properties of Ti-6Al-4V were modified by nanosecond laser irradiation. Three types of microstructures were created after the laser processing, the irradiated samples initially showed hydrophilic behavior, however, over time, these surfaces became hydrophobic with contact angles above 90°, and the maximum contact angle could reach 137°. The change from hydrophilicity to hydrophobicity was related to surface morphology, but it was not completely determined by surface morphology, because directly after laser treatment, the surface morphology was already formed and would not change by time. Through surface chemistry analysis, the explanation for the time dependency of the surface wettability was the modification of surface chemical composition, the increased carbon content on Ti-6Al-4V was proposed to be responsible for the hydrophobic behavior observed on the surface.