Fabrication of superhydrophobic surface on AISI316L stainless steel using a nanosecond pulse laser

Laser texturing process is a promising method to alter the wettability of metal surface on which micro/nano rough structures are created for changing the contact angle between the textured surface and liquid droplet. This paper aims at fabricating a superhydrophobic surface on AISI316L stainless steel, and a nanosecond pulse laser was employed for texturing line and point patterns on the metal surface. The influences of texturing patterns, laser power, scan speed, irradiation duration, and aging hours on the water contact angle and morphology of workpiece surface were investigated. According to the results, the hydrophilic surface was obtained right after the texturing process, and the surface turned to be hydrophobic after being left in ambient air for 15 days. The aging of laser-textured surface was also performed to induce the chemisorption of hydrocarbons toward the surface. This post process was able to shorten the hydrophilic-to-hydrophobic transition from days to a few hours. The aging duration of 2 and 0.5 h was respectively recommended for yielding and stabilizing the superhydrophobicity on line- and point-patterned surfaces. The maximum contact angle of 159.61° was achievable when the point pattern was textured on the stainless steel surface by using the laser power of 10 W and irradiation duration of 0.18 ms.