▎ 摘　　要

Present work addresses the synthesis of different structural forms of polyaniline (PANI) and their nanocomposites with graphene as functional fillers to epoxy coating for minimizing mild steel corrosion. The 7C-7C interactions between p-phenylenediamine functionalized graphene (fGO) and aromatic rings of in-situ grown covalently linked PANI on fGO facilitated the interfacial wrapping of graphene skeleton by PANI. The chemical, morphological, crystalline, and structural features of fGO-PANI nanocomposites are probed by FTIR, NMR, Raman, XPS, XRD, SEM, and HRTEM analyses. The emeraldine salt form of PANI (PANI-ES) exhibited significantly higher impedance and better corrosion inhibition properties than the emeraldine base (PANI-EB). Graphene skeleton in the fGO-PANI nanocomposite notably enhanced the anticorrosive properties of PANI with a multifold increase in total impedance. The 2D graphene skeleton in fGO-PANI nanocomposites provides excellent surface coverage as a structural barrier and increases the number of possible electron transfer pathways. Moreover, the oxidoreduction properties of PANI make the fGO-PANI-ES nanocomposite highly effective in increasing the impedance by multifolds. The corrosion protective mechanism of fGO-PANI-ES is discussed by emphasizing the role of graphene, different structural forms of PANI, and the dosing of graphene in fGO-PANI nanocomposites. The present work revealed fGO-PANI-ES as a promising material for new generation coatings to mitigate mild steel corrosion, particularly in a maritime environment.