Asymmetric Gemini surfactants as corrosion inhibitors for carbon steel in acidic medium: Experimental and theoretical studies

作者：Xie, Yangchun; He, Xiaohua^*

来源：Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2023, 660: 130850.

DOI：10.1016/j.colsurfa.2022.130850

• Asymmetry
• Electrochemical measurements
• Inhibitor
• Surfactant
• Theoretical calculations

Asymmetric Gemini surfactants are a kind of novel surfactants with corrosion resistance ability, which are ex-pected to be widely used in metal anti-corrosion during the pickling treatment. In this work, two asymmetric Gemini surfactants, N1-(3-dodecanamidopropyl)-N3-dodecyl-2-hydroxy-N1,N1,N3,N3-tetramethylpropane-1,3-diammonium (surfactant I) and N1-(3-dodecanamidopropyl)-N3-tetradecyl-2-hydroxy-N1,N1,N3,N3-tetramethyl-propane-1,3-diammonium (surfactant II), were utilized as the corrosion inhibitor for A3 carbon steel in acidic medium. Weight-loss measurements indicated that the inhibition efficiency (eta w%) increased with increasing asymmetry degree, and the maximum values of eta w% for surfactants I and II reached 98.37% and 97.21% at 85 degrees C, respectively. The adsorption of these surfactants obeyed the Langmuir adsorption isotherm. The electrochemical measurements suggested that the two surfactants would serve as mixed-type inhibitors. The results obtained from scanning electron microscope (SEM), atomic Force Microscope (AFM) and X-ray diffraction characterizations (XRD) were in accordance with the experimental results that surfactants I and II are effective inhibitors for the metal in acidic medium. The quantum chemical study and Molecular dynamics (MD) simulation further sup-ported the experimental results and provided insight into a deeper understanding of the inhibition mechanism of asymmetric Gemini surfactants.