Microcapsule/silica dual-fillers for self-healing, self-reporting and corrosion protection properties of waterborne epoxy coatings

Abstract

Smart anticorrosive coatings were prepared by adding microcapsules and silica nanoparticles (SNs) in waterborne epoxy matrix and applied on galvanized steel substrates. The microcapsules encapsulated crystal violet lactone (CVL), epoxy monomer and phenyl acetate in methyl methacrylate polymer shell, so that the self-healing and self-reporting functions can be simultaneously realized. SNs can trigger the chromogenic reaction of CVL, while improving the corrosion protection properties of the composite coatings. The comprehensive properties of the coatings were investigated as a function of the weight ratio of CVL/epoxy monomer in microcapsules, the filling content of SNs and microcapsules, as well as the change of pH value. The corrosion current density of the composite coatings decreased with the SNs content and increased with the microcapsule content. Smart coatings with corrosion current density of 2.91 × 10−12 A cm−2 were achieved by adding 15 wt% microcapsules and 15 wt% SNs in epoxy matrix.