Time-dependent anisotropic wetting behavior of deterministic structures of different strut widths on Ti6Al4V

Abstract

This study investigated the wetting behavior of Ti6Al4V surfaces that were groove-structured by means of femtosecond laser irradiation. The material was treated under ambient air conditions by use of a laser wavelength of 1030 nm and a pulse duration of 300 fs. Highly accurate structures with a gap width of 20 µm, a gap depth of 10 µm, and varying strut widths (1–300 µm) were generated and the contact angles in parallel and perpendicular direction were determined using sessile drop method with ultrapure water 1, 8, and 15 days after irradiation. All deterministic surfaces exhibited a pronounced contact angle change over time. The structures showed a strong anisotropic wetting behavior with a maximum contact angle aspect ratio of 2.47 at a strut width of 40 µm and a maximum difference between the parallel and perpendicular contact angle of 47.9° after 1 day.