Achieving superior anticorrosion and antibiofouling performance of polyaniline/graphitic carbon nitride composite coating

Microorganisms sticking to the coating's surface might hasten its demise, and corrosive ions are more capable of penetrating the coating-substrate contact, resulting in local corrosion of carbon steel, which is an urgent scientific and engineering problem to be solved. Herein, bifunctional anticorrosion and antibiofouling coatings were prepared using polyaniline (PANI) and graphitic carbon nitride (CN) incorporated with epoxy (EP) resins. The electrochemical tests' results, such as coating open circuit potential (OCP), electrochemical impedance spectra (EIS), and polarization curves, revealed that the optimum PANI@CN-10/EP coating possesses outstanding corrosion resistance. The Icorr of 1.05 × 10−10 A·cm−2 for PANI@CN-10/EP coating is one order of magnitude lower than that of EP coating (3.46 × 10−9 A·cm−2), and the impedance radius of 1.62 × 1010 Ω·cm2 is two orders of magnitude higher than that of pure phase EP (4.56 × 108 Ω·cm2). In addition, the antibiofouling tests presented that PANI@CN/EP coating had favorable anti-biofouling properties with only a tiny number of algae (Phaeocystis globose and Skeletonema costatum) adhered to the surface. This study presents the application of bifunctional composite coatings combining anticorrosion and antibiofouling.