On the nature of inhibition performance of imidazole on iron surface

Quantum mechanical calculations based on the Density Functional Theory under periodic boundary conditions were used to construct a model for the inhibition performance of imidazole on iron surface. It is shown that, at high coverage, imidazole molecules form C–C intermolecular bonds creating a protective film, which constitutes a hydrophobic medium and, consequently, prevents adsorption of water molecules. The establishment of intermolecular bonds leads to a stabilization of the adsorption energy and this cooperative effect is the thermodynamic explanation for the film formation. These results also point out to the limitation of previous studies based on properties of isolated inhibitor molecules.

► Imidazole corrosion inhibition performance. ► Slab model and periodic DFT. ► Cooperative effect on adsorption. ► Polymerization of imidazole molecules at high coverage. ► Protective film.