Self-healing microcapsules integrating montmorillonite and hydrotalcite: A corrosion inhibition strategy in multiple polluted environments

Multiple polluted environments accelerate the corrosion of metal coatings. Here, microcapsules of pretreated montmorillonite (MMT) and layered double hydrotalcite (LDH) encapsulated repair agents were prepared by a simple and effective method and applied to epoxy coatings. The microcapsules efficiently adsorbed Congo red (CR), copper ions (Cu²⁺), and chloride ions (Cl⁻). Moreover, the coating doped microcapsules demonstrated a remarkable 334.6% improvement in its self-healing capability. After 40 days of exposure to a multiple polluted environments, the composite coating maintained a corrosion resistance efficiency of 99.01%. The experimental and theoretical methods prove that MMT/LDH efficiently adsorbed corrosive pollutants through ion exchange, coordination complexation, and electrostatic interaction, while the self-healing product achieved microcrack closure through hydrogen bonding and van der Waals force between atoms. This work can provide new insights and assistance for the study of corrosion inhibition mechanisms under multiple polluted environments.