Preparation of silica-epoxy superhydrophobic coating with mechanical stability and multifunctional performance via one-step approach

Functionalized nanoparticles can provide the required rough structures and properties, which are an effective way to construct superhydrophobic surfaces. Yet, these surfaces have problems of complicated fabrication and poor adhesive strength. Based on the above problems, the hydrophilic SiO2 nanoparticles are modified with low-surface-energy 1 H, 1 H, 2 H, 2 H-perfluorodecyltrimethylsilane (FAS-17) to synthesize fluorosilane-modified SiO2 (FS) nanoparticles. Furthermore, epoxy resin (EP) containing stable benzene ring and ether bond was introduced as adhesive and anti-corrosion substance to form the superhydrophobic FSEP coating by a one-step approach. The as-prepared coating exhibits high water repellency and adhesion on various substrates, with water contact angle of 162.0º and rolling angle of 2.6º. The coating can withstand 550 cm sandpaper abrasion and resist water droplets with different pH values, showing good mechanical and chemical stability. Additionally, it possesses good durability after weathering in air for 30 d or immersing in saline for 14 d. Moreover, the coating demonstrates excellent multifunctional performance in anti-corrosion, drag reduction and self-cleaning, and its mechanisms of multifunctional applications are analyzed and revealed in detail. It is noteworthy that the corrosion current is decreased by 3 orders of magnitude and the drag reduction rate is enhanced by 28.06 %, after spraying the FSEP coating on the aluminum alloy. This work establishes multifunctional superhydrophobic coating through a simple and effective one-step approach, which will further expand the production scale of superhydrophobic coatings and facilitate their practical applications.