Hydrogels are formed through the cross-linking of hydrophilic polymer chains within an aqueous microenvironment. A novel synthesis strategy, UV-initiated frontal polymerization to quickly synthesize bubble-free, self-propagating hydrogel anticorrosive coatings in aqueous conditions, was presented, in which the self-propagating polymerization rate reached 16.7 mm min-1. SEM, AFM, FTIR, EIS, IC, XPS, and ultra-depth-of-field microscopy were used to characterize the surface morphology and anti-corrosion properties of the hydrogel coating. The addition of nano-SiO2 formed dense hydrogen bonds, and the stability of the three-dimensional network was enhanced. Underwater, the hydrogel coating could physically block corrosive media from reaching steel surfaces, and it was 75% effective at blocking chloride ions after 7 days under osmotic pressure. In addition, 1,2,4-triazole accumulated on the steel surface, and then the active anti-corrosion function took effect. This paper provides the basis for the in situ synthesis of hydrogel anticorrosive coatings on the surface of mild steel in a wet or underwater state.
Keywords: UV-initiated frontal polymerization; anticorrosive coatings; hydrogels; in situ synthesis; self-propagating.