Evaluation of the antimicrobial corrosion properties of electropolymerized poly(aniline-co-o-toluidine) films on carbon steel surfaces

Microbiologically influenced corrosion (MIC) can lead to structural weakening and shortened service life of carbon steel, resulting in serious economic losses and safety hazards. In particular, sulfate-reducing bacteria (SRB) produce hydrogen sulfide and sulfide during their growth and metabolism, which accelerates the corrosion of carbon steel. Thin films of poly(aniline-co-o-toluidine) (PA-co-POT) were electrodeposited on the surface of carbon steel using cyclic voltammetry in an electrolyte consisting of oxalic acid, aniline and o-toluidine monomers. The mechanical properties of the polymer films were analyzed by a micro-Vickers hardness tester. The corrosion resistance of the polymer films was evaluated by an electrochemical corrosion test and immersion test of the polymer films in a solution containing SRB and 3.5 % NaCl. The results showed that PA-co-POT films have superior SRB corrosion resistance than single polymer films. The corrosion rate of PA-co-POT film was 0.0171 mm/year, and the protection efficiency was 83 % after 14 days of immersion in solution. In addition, due to the antibacterial properties of the PA-co-POT film, the adhesion of bacteria on its surface is significantly reduced, and local corrosion is also effectively inhibited. This study demonstrates the potential of electropolymerized aniline derivative copolymer films in preventing MIC of carbon steel and provides valuable insights for the development of new corrosion protection materials.