Preparation and properties of functionalized nano-TiO₂/epoxy resin superhydrophobic anticorrosive composite coating

Superhydrophobic materials have great potential application prospects in the field of metal anticorrosion. In order to obtain TiO₂/epoxy resin composite coating material with excellent corrosion resistance, firstly, the surface of nano-TiO₂ was modified with trimethoxy heptafluorodecyl silane and γ-aminopropyltriethoxysilane (KH550), and then the diethylenetriamine (DETA) as curing agent was fluorinated with perfluorooctyl methacrylate. Finally, two kinds of composite coatings were prepared by blending method and two-step method respectively. The phase composition and microstructure of fluorinated curing agent (F-DETA) and fluorinated nano TiO₂ (f-TiO₂) were analyzed by FTIR, XPS and ¹HNMR. The contact angle tester and static test show that when the molar ratio of trimethoxyheptafluorodecyl silane to γ-aminopropyltriethoxysilane is 1∶15, the performance of f-TiO₂ is the best. The contact angle of the composite coating reaches 164.9°. SEM was used to characterize the micro-morphology of the coating surface and cross-section. The results show that the f-TiO₂/epoxy resin composite coating prepared by two-step method has uniform rough surface, low porosity inside the coating, and gradient structure between epoxy resin layer and f-TiO₂ layer. The friction experiment proves that the super hydrophobicity of f-TiO₂/epoxy resin composite coating prepared by two-step method has certain mechanical stability. Tafel polarization curve and electrochemical impedance spectroscopy (EIS) show that the f-TiO₂/epoxy resin composite coating prepared by two-step method has excellent corrosion resistance, and its corrosion inhibition efficiency is as high as 99.99%.