Superhydrophobic surface fabricated by nanosecond laser and perhydropolysilazane

Abstract Superhydrophobic surfaces have attracted much interest in science research and actual engineering applications. In this study, the nanosecond laser technology on the surface of carbon steel and functional surface modification by the perhydropolysilazane (PHPS) coating with the repeating unit of (SiH2NH) were used to obtain a novel carbon steel material with superhydrophobic property. Through the selected treatment of nanosecond laser, the periodic micro/nanostructures were formed on the surface of carbon steel and changed in the surface roughness of the substrate was observed. A new, cheap and environmental low surface energy alternative is used to apply on micro/nanostructures in order to reach stable and long-acting superhydrophobic state. The surface free energy of coating is 18.64 mN/m by calculating follow the two-liqudi and three-liquid methods. Further adding PHPS coatings, we found that the as-synthesized surfaces exhibited outstanding water repellence (water contact angle (WCA) = 163.9°) and non-stickiness behavior (sliding angle (SA) = 1.7°), which is attributed to low surface free energy of PHPS coating. In addition, the modified carbon steel materials were very stable and long-acting, which can remain superhydrophobic behavior in air without an obvious decay of water contact angle after 90 days. The combination of micro/nanostructures and coating possesses excellent mechanical durability, presenting broad application prospects.