Hydrophobic fumed silica/epoxy coating: the impact of solvents on its hydrophobicity and durability

In this study, the effect of the solvents on the formation of superhydrophobic fumed silica/ FAS-17/epoxy surfaces modified by the incorporation of hydrophobic fumed silica nanoparticles was investigated. We used three different solvents, namely n-butyl acetate, ethyl acetate, and dichloromethane, to develop a superhydrophobic surface using the easily applicable doctor's blade method. Surfaces obtained were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). The performances of the different solvent-based coated surfaces were compared by measuring the contact angle (CA) of three liquids, sliding angles (SA), surface friction force, environmental adaptability, and self-cleaning performance. The water contact angles (WCAs) of the n-butyl acetate, ethyl acetate, and dichloromethane-based coated surfaces were 149.70°±5.52°, 146.89°±3.7°, and 147.34°±2.50°, respectively, which were 150.36°±4.03°, 147.53°±4.97°, and 148.68°±3.36° for a 3.5% NaCl solution. Comparing the wettability, environmental durability, and self-cleaning performance of the different solvent-based coated surfaces, n-butyl-acetate-based coated surfaces showed better performance compared to ethyl-acetate- or dichloromethane-based coated surfaces.