Novel benzimidazole derivatives as corrosion inhibitors of mild steel in the acidic media. Part II: Theoretical studies

•Quantum chemical and MD studies of benzimidazole derivatives inhibitors.•Inhibition effectiveness depends on the ability to accept electrons.•Active sites of adsorption are mainly centralized on imidazole rings.•Steric effect results in the non-planar adsorption of BBIA and TBIA.

In this paper, the adsorption behavior and inhibition mechanism of 2-aminomethyl benzimidazole (ABI), bis(2-benzimidazolylmethyl) amine (BBIA) and tri-(2-benzimidazolylmethyl) amine (TBIA) on the surface of mild steel were studied by quantum chemical calculations and molecular dynamics (MD) simulations. It was found that the three molecules show the similar ability to donate electrons while the difference in inhibition performance should mainly be attributed to the difference in accepting electrons. MD simulations show that steric effect between the benzimidazole segments significantly affects the adsorptive configurations of the molecules on Fe (1 0 0) surface.