A New Strategy for Long-Term Smart Corrosion Protection of Q235 Carbon Steel Using Polyaniline Nanofiber Covalently Linking with Modified GO as Reinforcement of Epoxy Coating

Polyaniline nanofiber (PANI-f) was covalently linked with cetyltrimethyl ammonium bromide (CTAB) modified graphene oxide nanosheets (CTGO) to fabricate a smart composite coating for corrosion protection of carbon steel. In the copolymerization process, CTAB served both as a modifier for the modification of GO and a dispersant for the preparation of polyaniline nanofibers. The prepared PANI-f can avoid the accelerated corrosion of steel by a conventional synthesis method using hydrochloric acid as medium. The covalent binding between PANI-f and CTGO improved the compatibility of PANI-f-GO with the waterborne epoxy emulsion, which significantly enhanced the hydrophobicity and antipermeability of the coating. The PANI-f-GO waterborne epoxy coating exhibited excellent smart corrosion protection efficiency by catalyzing the formation of passivation film on the steel surface. Molecular adsorption energy on Fe(110) and radial distribution function confirmed the chemical adsorption of the PANI-f-GO composite on the steel surface. The superior smart protective performance can be ascribed to the synergistic effects of PANI-f and CTGO.