TY - JOUR
T1 - Electrochemical behavior and corrosion resistance of the electropolymerized poly(o-toluidine-co-dopamine) film on stainless steel substrates
AU - Huang, Xing
AU - Huang, Kai
AU - Xiang, Huan
AU - Tan, Yao
AU - Yin, Huawei
AU - Tang, Chengli
AU - Li, Tingzhen
AU - Hu, Chuanbo
N1 - Publisher Copyright:
© 2025 Elsevier B.V.
Funding Information:
This work was supported by the Natural Science Foundation of Chongqing (Grant No. CSTB2024NSCQ-MSX1013), the Science and Technology Research Program of Chongqing Municipal Education Commission (Grant Nos. KJZD-K202304502 and KJZD-M202301201), the Talent Program of Changshou (CSYC2025–002), the Natural Science Foundation of Chongqing (Grant Nos. CSTB2024NSCQ-MSX1013 and CSTB2025NSCQ-LZX0103) and the Opening Project of Material Corrosion and Protection Key Laboratory of Sichuan province (Grant No. 2024CL05).
PY - 2025/10/1
Y1 - 2025/10/1
N2 - This study successfully electrodeposited a copolymer of poly(o-toluidine) and poly(dopamine) (POT-co-PDA) onto 304 stainless steel substrates using cyclic voltammetry in a sulfuric acid medium, employing o-toluidine and dopamine hydrochloride as comonomers. Characterization results from ultraviolet-visible (UV–vis) absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy confirmed the successful synthesis of the copolymer. Scanning electron microscopy (SEM) analysis revealed that the POT-co-PDA copolymer film exhibited a denser and more continuous surface morphology compared to the porous structure of the homopolymer, indicating that the incorporation of dopamine effectively refined the film's microstructure. The electrochemical corrosion performance of the coatings was evaluated through accelerated immersion tests in a 3.5 % NaCl solution. Initially, Tafel polarization curve measurements demonstrated that both POT and POT-co-PDA coatings significantly enhanced the corrosion resistance of the stainless steel substrate. Notably, the POT-co-PDA coating exhibited superior protective performance, achieving a corrosion rate as low as 0.009 mm/year and a protection efficiency of 92.64 % for the substrate. Furthermore, electrochemical impedance spectroscopy (EIS) results revealed that the charge transfer resistance (Rct) value of the POT-co-PDA coating was 3.5 times and 6.8 times higher than that of the POT homopolymer coating and the bare steel substrate, respectively. This further confirms its significantly enhanced long-term barrier protection capability. The markedly improved corrosion protection performance of the POT-co-PDA coating primarily stems from the multifunctional role of the dopamine units within the copolymer. These units synergistically enhance the coating's physical barrier properties and electrochemical passivation capabilities. Key mechanisms include enhanced interfacial adhesion, increased film compactness, and the passivation effect facilitated by the catechol groups in PDA.
AB - This study successfully electrodeposited a copolymer of poly(o-toluidine) and poly(dopamine) (POT-co-PDA) onto 304 stainless steel substrates using cyclic voltammetry in a sulfuric acid medium, employing o-toluidine and dopamine hydrochloride as comonomers. Characterization results from ultraviolet-visible (UV–vis) absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy confirmed the successful synthesis of the copolymer. Scanning electron microscopy (SEM) analysis revealed that the POT-co-PDA copolymer film exhibited a denser and more continuous surface morphology compared to the porous structure of the homopolymer, indicating that the incorporation of dopamine effectively refined the film's microstructure. The electrochemical corrosion performance of the coatings was evaluated through accelerated immersion tests in a 3.5 % NaCl solution. Initially, Tafel polarization curve measurements demonstrated that both POT and POT-co-PDA coatings significantly enhanced the corrosion resistance of the stainless steel substrate. Notably, the POT-co-PDA coating exhibited superior protective performance, achieving a corrosion rate as low as 0.009 mm/year and a protection efficiency of 92.64 % for the substrate. Furthermore, electrochemical impedance spectroscopy (EIS) results revealed that the charge transfer resistance (Rct) value of the POT-co-PDA coating was 3.5 times and 6.8 times higher than that of the POT homopolymer coating and the bare steel substrate, respectively. This further confirms its significantly enhanced long-term barrier protection capability. The markedly improved corrosion protection performance of the POT-co-PDA coating primarily stems from the multifunctional role of the dopamine units within the copolymer. These units synergistically enhance the coating's physical barrier properties and electrochemical passivation capabilities. Key mechanisms include enhanced interfacial adhesion, increased film compactness, and the passivation effect facilitated by the catechol groups in PDA.
KW - Copolymer
KW - Cyclic voltammetry
KW - Corrosion protection
KW - Interfacial adhesion
KW - Passivation
UR - https://www.scopus.com/pages/publications/105016891270
U2 - 10.1016/j.surfin.2025.107739
DO - 10.1016/j.surfin.2025.107739
M3 - Journal article
AN - SCOPUS:105016891270
SN - 2468-0230
VL - 74
JO - Surfaces and Interfaces
JF - Surfaces and Interfaces
M1 - 107739
ER -