Surface characteristics and wettability of superhydrophobic silanized inorganic glass coating surfaces textured with a picosecond laser

In this study, picosecond laser texturing was applied to enamel (an inorganic glass material) with micro-features that were then covalently absorbed with fluorosilane agents to produce superhydrophobic coatings. The resultant surfaces showed multiscaled structures of broccoli-like and cone-shaped pillars that resulted in excellent water-repelling properties with a water contact angle approaching 180°. The results proposed a surface area index to obtain the Cassie-Baxter hydrophobic state. The study also discussed the correlation of surface areal parameters to the Cassie-Baxter non-wetting state of the silanized samples. Most laser textured samples of ultrahigh water contact angles had similar surface metrological characteristics to natural leaves like alocasia odora and agave. The sample hierarchical surface structures had waviness constituents of platykurtic distribution, which were decorated with nano-submicron remelted enamel debris, which had leptokurtic distribution. The study has demonstrated the significant roles of surface metrology in the production of hierarchical morphologies to achieve the stable Cassie-Baxter superhydrophobicity.