Chemistry of the interaction between Imidazole derivatives as corrosion inhibitors molecules and copper/brass/zinc surfaces: A DFT, reactive and classical molecular force fields study

In the present research, we explored the corrosion inhibition mechanisms on metals and alloys by imidazole, methylimidazole, and benzimidazole applying density functional theory (DFT), reactive (ReaxFF), and classical force fields. Our investigation focused on the interaction of these molecules with different types of bare metal surfaces. The results of our studies have been compiled to compare the protection efficiency of the three organic molecules for copper, zinc, and copper-zinc alloys (Cu63%-Zn37%) exposed to the same corrosion conditions in an acid environment. The calculated interaction energy quantities are strongly correlated with the experimental corrosion inhibition efficiencies BIM > MIM > IM. The imidazole derivative studied, significantly better protect copper than zinc, which is attributed to the higher bond strength of Cu–N (formation of chemical bonds) than of Zn–N, confirms the increase in the protection effectiveness against corrosion of Zn < Cu63%-Zn37% < Cu. This present study demonstrates the enormous potential of ReaxFF calculations to accurately simulate the adsorption of inhibitor molecules onto metal surfaces at a fraction of the computational cost of DFT, as well as the performance of the umbrella sampling method to assess the adsorption free energies.