Fabrication of durable corrosion-resistant polyurethane/SiO₂ nanoparticle composite coating on aluminium

In this work, SiO₂ nanoparticle–embedded polyurethane superhydrophobic coating on aluminium substrate was fabricated using spin coating technique. By embedding SiO₂ nanoparticles into the polyurethane matrix, superhydrophobicity is successfully achieved with water static contact angle of 156 ± 3° and tilt angle of 6 ± 1°. Coating exhibits excellent self-cleaning and antifouling properties. Wetting stability of coating was further evaluated by performing water jet, bending, sand falling, tape peeling, floating, annealing, and chemical stability tests. It is found that coating is mechanically, thermally, and chemically stable. Water droplet impact test shows the bouncing, pinning, and splashing behaviour of water droplets at different impact velocities. The electrochemical experiment has demonstrated that the corrosion potential of aluminium after coating increases and the corrosion current density decreases, revealing the corrosion resistance property of coating. We envision that the self-cleaning, antifouling, and anticorrosive superhydrophobic coating of the polyurethane/SiO₂ nanoparticle composite can effectively prevent the corrosion of aluminium and the aforesaid coating has great industrial applications.