Synergistic corrosion protection and antibacterial efficacy of electrochemically deposited anion-doped polyaniline on 304 stainless steel

• J.T. Wang, B.C. Jiang, D.F. Shi, J. Liu, B.H. Dong and X.Y. Xing

Jiangsu Shipping College, Nantong 226010, China

Abstract: Polyaniline (PANI) coatings have emerged as a promising approach for enhancing the durability of stainless steel surfaces. This study examines the electrochemical synthesis of PANI coatings on 304 stainless steel (304SS) and assesses their anticorrosion and antibacterial properties. The coatings, deposited via galvanostatic polymerization, display uniform thickness (~20 μm) and strong adhesion, as verified by scanning electron microscopy (SEM), the ISO 2409 grid method and Fourier-transform infrared spectroscopy (FTIR). Electrochemical impedance spectroscopy (EIS) and polarization resistance measurements demonstrate that the PANI coatings markedly reduce corrosion rates by forming a protective barrier and facilitating anodic protection, alongside exhibiting catalytic activity toward oxygen reduction. In terms of antibacterial performance, the coatings disrupt bacterial cell walls through electrostatic interactions, effectively inhibiting Vibrio natriegens attachment. However, extended immersion leads to coating degradation and a consequent decline in antibacterial efficacy. Notably, the study reveals that acid-doped PANI (e.g., with HCl, H₃PO₄, or camphorsulfonic acid) exhibits superior antibacterial performance compared to undoped PANI, owing to the modulation of surface charge distribution and redox activity by dopant anions. These findings underscore the potential of PANI coatings for industrial applications requiring long-term corrosion resistance, while also highlighting the crucial influence of doping strategies in optimizing coating performance.

Keywords: 304 stainless steel, polyaniline coatings, corrosion resistance, antibacterial activity, doping anions, electrochemical synthesis

Int. J. Corros. Scale Inhib., 2025, 14, no. 4, 1942-1962
doi: 10.17675/2305-6894-2025-14-4-12

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