Purpose This study aims to investigates the protective performance of three benzimidazole derivatives, namely, benzimidazole (B1), 2-methylbenzimidazole (B2) and 2-mercaptobenzimidazole (B3), on the corrosion of mild steel in 1.0 M HCl medium. Design/methodology/approach Density functional theory (DFT) and molecular dynamics (MD) simulations were employed alongside complementary analyses, including non-covalent interaction (NCI) index, mean square displacement (MSD) calculations, fractional free volume (FFV) and radial distribution function (RDF). Furthermore, global reactivity parameters, including (HOMO-LUMO) energies, energy gap (ΔE), global softness (σ), electronegativity (χ), electrophilicity index (ω), global hardness (η) and electron transfer (ΔN) were calculated and analyzed using various basis sets 3-21G, 6-31G, 6-31G++ and 6-31G++(d,p). Findings MSD and FFV analyses showed a decrease in the mobility of corrosive species, suggesting a more restricted diffusion environment. Meanwhile, the RDF analysis revealed mixed adsorption behavior, with chemisorption being the dominant interaction mode for all three inhibitors. The simultaneous contribution of weak non-covalent and strong electrostatic interactions defines the interaction framework of the studied systems. The binding energy values follow the order B3 (1193.52 kJ·mol-¹) B2 (1104.67 kJ·mol-¹) B1 (964.63 kJ·mol-¹), indicating that B3 exhibits the strongest interaction with the metal surface. The corrosion inhibition performance of the benzimidazole derivatives increases in the following order: B3 B2 B1. Originality/value This work investigates the link between the corrosion inhibition performance of benzimidazole derivatives on mild steel and their theoretical assessment using DFT and MD simulations.
Amrane et al. (2026) studied this question.