Benzotriazole inbuilt hollow mesoporous CeO2 microsphere encapsuled by polydopamine/polyethyleneimine co-deposition layer for dual active corrosion protection of waterborne epoxy coated steel

In this work, a new type of hollow mesoporous CeO₂ microsphere (HMCM), synthesized through a template-free approach, was utilized as both an inhibitor and a nanocontainer for loading the corrosion inhibitor benzotriazole (BTA). These microspheres were encapsulated with a co-deposition layer composed of polydopamine (PDA) and polyethyleneimine (PEI) to construct smart containers (PDA-PEI@HMCM-BTA) with pH-responsive release properties. The corrosion inhibition effect of PDA-PEI@HMCM-BTA nanocontainers was assessed and the release rate of BTA and Ce ions from the nanocontainers was greatly accelerated in the presence of acidic solutions. Electrochemical impedance spectroscopy (EIS) was conducted to evaluate the barrier properties and active anti-corrosion performance of the coatings. The results showed that the integration of nanocontainers within the waterborne epoxy coating significantly improved the corrosion resistance and self-healing capabilities, thereby providing efficient corrosion protection for carbon steels. The method offered a simplified synthesis route for Ce-based nanocontainers and presented a strategy for producing waterborne epoxy coatings with active anticorrosive properties.