Facile and eco-friendly fabrication of superhydrophilic and superhydrophobic SiC surfaces by nanosecond laser treatment

Superhydrophobic silicon carbide surfaces have garnered substantial attention for their potential applications in aerospace, ship domain, military, etc., fields. In this work, we used a nanosecond laser (λ = 1065 nm) and fluorine-free N-octyltriethoxysilane (OcTES) to fabricate SiC surfaces capable of transitioning from superhydrophilic to superhydrophobic. Superhydrophilic surfaces were produced within minutes through laser treatment, and the time required to convert it to superhydrophobic surfaces is only 1 h. The apparent water contact angle (WCA) of superhydrophilic SiC could reach the saturated Wenzel regime. The number of hydrophilic polar bonds on SiC surfaces increased while nonpolar bonds of hydrophobicity decreased due to oxidation during laser treatment. After OcTES treatment, the SiC surface transformed from superhydrophilic to superhydrophobic (WCA of 153° and roll-off angle of 0°). These results indicate that surface roughness and chemical compositions are critical for superhydrophobicity. It was discovered that Si–O–Si groups were formed on SiC surfaces in the atmosphere, thereby enhancing the material surface's hydrophobicity. Superhydrophobic SiC surfaces also have excellent low-adhesion and anti-icing properties, making them of potential interest for functional ceramic surface applications.