Surface and thermodynamic parameters of some cationic corrosion inhibitors

Four cationic corrosion inhibitors were prepared having the general formula ClRN⁺H₂(CH₂)_nN⁺H₂RCl, where R is a hydrogen atom or benzyl group, n = 8 or 10. Determines the critical micelle concentration (CMC) at 38, 48 and 58°C. Also investigates structural effects on the CMC, maximum surface excess (Γ_max), and minimum area per molecule (A_min) at the aqueous solutions/air interface. Shows that these inhibitors provided a powerful corrosion inhibition of steel in sulphuric acid solution at temperatures up to 78°C. Also indicates that the alkylation process improved surface and thermodynamic properties, consequently attaining better inhibition effects.