Improvement of active corrosion protection of carbon steel by water-based epoxy coating with smart CeO^sub 2^ nanocontainers

Water-based epoxy coating containing CeO2 nanocontainers was successfully applied on carbon steel for corrosion protection. CeO2 nanocontainers were loaded with the corrosion inhibitor benzotriazole (BTA). Polyelectrolyte multilayers were deposited on the loaded nanocontainers by layer-by-layer assembly method. Responsive release of BTA molecules were studied in water media at different pH values using UV–vis spectroscopy. The anticorrosive performance of the epoxy coatings doped with 0.5 wt% of smart nanocontainers was tested by immersion of the coated carbon steel in 0.5 M NaCl solution. Electrochemical impedance spectroscopy (EIS) was used to estimate the influence of smart nanocontainers on the passive corrosion resistance. The self-healing performance of the coating with modified CeO2 nanocontainers was studied by scanning Kelvin probe (SKP). From results of EIS and SKP, the addition of pH-sensitive nanocontainers into the epoxy resin inhibited the corrosion activities on the metal surface, showing a promising strategy for developing water-based epoxy coatings with long term protection performance.