Durable and anti-corrosion superhydrophobic coating with bistratal structure prepared by ambient curing

Limited durability, poor anti-corrosion property and complex synthesis procedure are the major obstacles to the practical application of superhydrophobic coatings, especially for room-temperature curing superhydrophobic coatings. To address these problems, a versatile superhydrophobic coating embedding with carbon nanotubes and silica nanoparticles was fabricated in this work via facile spraying and ambient curing technique, utilizing epoxy resin as film-forming material. With the surface modification of 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS), the prepared surface demonstrated an excellent superhydrophobicity with a water contact angle (WCA) of 164 ± 1.5° and a sliding angle (SA) of 4 ± 0.5°. The inorganic particle and the organic resin together constructed a unique bistratal structure consisting of superficial protrusions and underlying porous structures. The mechanical property of the coating was improved by their synergistic effect. Furthermore, the underlying porous structures could capture more air to form a stable air layer, which enhanced the self-cleaning property and durability of the superhydrophobic coating. Especially, the fabricated coating exhibited outstanding corrosion resistance, the corrosion current density of the coating was about 2.37 × 10−11 A/cm2, which was 2 and 4 orders of magnitude lower than that of the EP coating and the pure Al plate, respectively. Based on the electrochemical analysis, the anti-corrosion mechanism involving physical barrier and electrons transfer was proposed. The facile, economical method for preparing superhydrophobic coating has enormous application value in various fields.