Corrosion Resistance Study of Cyclocarboxypropyl Oleic Acid-Doped Polyaniline/Epoxy Composite Coatings

Corrosion inhibitors can form dense, protective layers on metal surfaces, thereby preventing the penetration of corrosive media and ensuring the long-term safety of industrial equipment and energy facilities. Polyaniline (PANI), renowned for its excellent conductivity and redox activity, not only facilitates the formation of passivation layers on metals but also mitigates pitting corrosion. In this study, a novel doped PANI was synthesized through chemical oxidation using cyclic carboxypropyl oleic acid (CCHOA) as a dopant, and its anti-corrosion properties were evaluated by incorporation into epoxy resin coatings. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) analyses confirmed that CCHOA-doped PANI produced a more uniform and compact microstructure with reduced agglomeration. The corrosion resistance and toughness of the epoxy coatings initially improved with increasing CCHOA content, but then slightly declined, which allowed us to determine the optimal doping level for PANI. The ideal concentration was found to be 0.5 mol/L in the epoxy resin matrix.