2-Mercaptobenzimidazole@carbon nanocages enable self-healing anticorrosion coatings

Self-healing anticorrosion coatings are attractive for extending the service-life of metals, especially in marine environments. This work reports the novel self-healing coatings based on (2-mercaptobenzimidazole)-loaded carbon nanocages (MBI@CNCs) embedded in a polymethyl methacrylate (PMMA) matrix. The carbon nanocages (CNCs) as inhibitor carriers provide abundant channels for loading and releasing of 2-mercaptobenzimidazole (MBI). Nanocomposite coatings containing 12 wt.% MBI@CNCs deliver the optimal anticorrosion performance as well as excellent self-healing properties when applied to carbon steels. After scratching the coatings in a corrosive medium, MBI molecules are released from the coating. The corrosion inhibitor then reacts with the metal surface to form a passivation layer by coordination and electrostatic effect. The general strategy combining the one-pot synthesis of CNCs and loading with a corrosion inhibitor is conducive to large-scale production and practical application of self-healing anticorrosion coatings.