Investigation of alkylamine self-assembled films on iron electrodes by SEM, FT-IR, EIS and molecular simulations

Alkylamine were used to form self-assembled films for the inhibition of the corrosion of iron in 0.5 M H2SO4 solution. The films were characterized by electrochemical impedance spectroscopy (EIS) and surface analysis techniques including SEM and FT-IR. EIS results indicate that the inhibition ability of these alkylamine self-assembled films depends on the immersion time and the alky chain length of the adsorbate. Both longer immersion time of the electrode in the solution and longer alky chain will result in stronger inhibition ability of the films. However, when the immersion time was increased over some critical point, the inhibition ability was almost invariable. Also when the chain length reached a certain degree such as 14 carbon atoms, the inhibition ability decreased on the contrary. The ability of the corrosion inhibition of the tetradecylamine and dodecylthiol mixed films improved remarkably comparing with the tetradecylamine or dodecylthiol single films. In addition, molecular simulation was used to discuss the adsorption mechanism and good agreement with electrochemical results was obtained.