Improving the anti-corrosive performance of an epoxy coating by ionic liquid modified layered double hydroxide nanocontainer

Background Functionalized composite coatings play a key role in protecting metals and alloys against corrosion in harsh environments. Methods Layered double hydroxide (LDH) modified with choline benzoate ionic liquid is successfully fabricated through coprecipitation and ion-exchange strategies, and then incorporated into an epoxy to generate the CB-LDH/EP composite coating. The anti-corrosive and self-healing abilities of the CB-LDH/EP are comprehensively evaluated. Significant findings The addition of CB-LDH active nanocontainer induces a clear increase in the polarization resistance of the coatings (from 9.36 × 10 6 to 4.35 × 10 8 Ω cm 2 ). Moreover, the localized corrosion of the coating surface can be considerably retarded according to the long-term immersion experiments. Such an obvious enhancement in the corrosion resistance is attributed to the synergistic mechanism between the components of the polymer coating. The inherent lamellar structures of LDH enhance the physical barrier effect of the coating. Benefiting from the outstanding ion-exchange behavior, the LDH can serve as a storage station for corrosive anions like chloridion, and simultaneously the released benzoate anions from LDH galleries play a role of active corrosion protection. In addition, the choline cations can be adsorbed to the LDH surface because of their polar groups, indicative of a further improvement in the anti-corrosive performance of the coating.