Robust Superhydrophobic and Repellent Coatings Based on Micro/Nano SiO2 and Fluorinated Epoxy

Superhydrophobic surfaces possess low mechanical strength, and can be easily contaminated by fluids with low surface tension, such as oil
this hinders their practical applications. In this study, fluorinated epoxy was prepared through the thiol-ene click reaction at first. The superhydrophobic surface with high oil-repellency was prepared by the addition of unmodified nano-SiO2 and micron-SiO2 to the fluorinated epoxy. The effect of the ratio of micro- and nano-silica particles on the morphology and wettability of the coating was investigated. It was shown that a re-entrant structure appears and FEP-S coating has good liquid repellency when the amounts of nano-SiO2 and micro-SiO2 are equal. The contact angles of the FEP-S coating (coating with the best liquid repellent performance) for water, glycerol, ethylene glycol, and diiodomethane were 158.6° ± 1.1°, 152.4° ± 0.9°, 153.4° ± 1.3°, and 140.7° ± 0.9°, respectively. In addition, the superhydrophobic coatings possess excellent mechanical and chemical durability, excellent performance in self-cleaning, corrosion resistance, and anti-icing properties. The preparation method of superhydrophobic coating is relatively simple
therefore, it has a wide range of applications and can also be applied to various substrates.