Molecular dynamics simulation of corrosive particle diffusion in benzimidazole inhibitor films

Diffusion of corrosive particles inside inhibitor films consisting of 2-mercaptobenzimidazole (2-SH-BI), 2-aminobenzimidazole (2-NH2-BI), 2-methylbenzimidazole (2-CH3-BI), and benzimidazole (BI) was investigated by molecular dynamics simulation. Diffusion coefficients of various corrosive particles in the films were calculated, following the same order of 2-SH-BI < 2-NH2-BI < 2-CH3-BI < BI. Fractional free volume, interaction between corrosive particles and films, and mobility of films were also investigated to illustrate the microscopic diffusion mechanism. As a result, it can be inferred that the order of inhibition efficiency is 2-SH-BI > 2-NH2-BI > 2-CH3-BI > BI, which is in good accordance with published experimental results.

Research highlights
► Inhibition performance was evaluated from hinderance of particle diffusion.
► Fractional free volume and mobility of inhibitor film were investigated.
► Interaction mechanism between corrosive particles and inhibitor film was discussed.
► Theoretical results were verified by reported experimental ones.