42 / 2021-06-29 10:49:12

Effect of low vacuum heat treatment on the wettability transition of laser-ablated stainless-steel surface

Superhydrophobic,Picosecond laser processing,Low adhesion

Inspired by natural creatures, superhydrophobic surfaces with unique adhesion properties have attracted significant scientific interest. In this study, micro-pillar arrays with different morphologies were fabricated on 304 stainless steel surfaces using picosecond laser direct writing by controlling the laser energy and the scanning times. With the subsequent low vacuum heat-treatment, these laser-patterned surfaces then present different wetting performances and rolling behaviors. Long-lasting superhydrophobic surfaces with low-adhesion were obtained, and a contact angle greater than 150° with a minimum sliding angle of 3.14° was observed, which could not be achieved on samples that were merely heat-treated or only treated in a low vacuum environment. These were mainly attributed to the adsorption of organic matter on the surface which reduced the surface free energy and the laser-processed micro- nano composite structures which altered the continuity of the solid-liquid contact line. By combining laser processing and low vacuum heat treatment, the wettability transition and adhesion control of laser-processed stainless steel were realized.