A smart healable anticorrosion coating with enhanced loading of benzotriazole enabled by ultra-highly exfoliated graphene and mussel-inspired chemistry

Abstract

Graphene-based nanomaterials encapsulated with corrosion inhibitors are promising materials for achieving smart coatings with healable properties. However, the low loading contents of inhibitors (10%–20%) and the cumbersome synthesis processes remain as urgent problems for practical applications. Here, we propose a novel strategy for preparing healable coatings with the enhanced loading of inhibitors enabled by ultra-highly exfoliated graphene and mussel-inspired chemistry. Ultra-highly exfoliated graphene (1355 m2/g) was achieved via a unique one-pot method of H2O2/KOH catalytic exfoliation and etching with residual KOH. Polydopamine (PDA), as a green corrosion inhibitor, effectively promoted the adsorption of benzotriazole (BTA) on graphene via facile co-adsorption. The corrosion perception of this smart coating with the dual healable effect of BTA/PDA was triggered by PDA decomposition from corrosion-induced pH variations. Thus, the coating exhibited an increased impedance modulus (3.31 × 1010 Ω cm2) even after 30 days of immersion (three orders of magnitude higher than that of an epoxy coating), owing to the outstanding barrier effect of the ultra-highly exfoliated graphene and high loading content of inhibitors (30%). This study has a great significance for the design of high-loading smart nanomaterials for sustainable smart systems.