Polydopamine improved anticorrosion of graphene on copper: Inhibiting galvanic corrosion and healing structure defects

• A strategy of solving galvanic corrosion and structure defects of graphene simultaneously was proposed. • Graphene healed by polydopamine has more complete structure and exhibits better impermeability for corrosion medium diffusion. • Electron transport between Cu and GR was blocked by the super-thin polydopamine layer and galvanic corrosion was inhibited. • The synergistic strengthening effect between graphene and polydopamine exhibits enhanced anticorrosion performance. Galvanic reaction and structure defect remained as two longstanding challenges seriously limit the anticorrosion application of graphene (GR). To improve anticorrosion performance of graphene as protect barrier for metals, in the present study, polydopamine (pDA)-graphene (pDA-GR) composites were synthesized on Cu substrate, manifesting pDA-wrapped-GR microstructural features. The experimental results indicated the defects intrinsically located in GR could be healed by pDA via π-π interaction, resulting in effectively improved corrosion resistance. The protection coefficient of pDA-GR is increased to 99.8%, higher than pristine GR. The mechanism concerning both better impermeability of few-defect-graphene and non-conductivity of pDA layer was proposed to inhibit the galvanic coupling reaction between GR and metal substrate. The compositing strategy provided herein may path a new way to improve the anticorrosion performance of GR.