How The Inhibition Performance Of Thiazole Derivatives Inhibitors Affected By Their Adsorption: A Molecular Simulation Study

In the realistic environment, inhibitor molecules would undergo the process of dissolution and diffusion in the solution. And then, due to the strong adsorption interact with metal surface, inhibitor molecules will adsorb onto the metal surface spontaneously and form inhibitor film to protect metal surface. However, due to the limitation of experimental conditions, it is difficult to gain the detailed information of the adsorption states of inhibitor film on surface, and hard to study the influence of external factors on inhibition performance. Therefore, Molecular dynamics simulation is adopted to investigate the adsorption mechanism of inhibitor on metal surface and study the influence of inhibitor concentration, inhibitor chain length and salt ion concentration on adsorption states and inhibition performance from the aspect of adsorption behavior.When the inhibitor molecules adsorbed onto surface, three interactions play important role: 1) electrostatic interaction; 2) the band between the negative atoms and metal surface; 3) hydrophobic chain interaction.Inhibitor concentration has a significant influence on inhibitor configuration. According to the analysis of density distribution, average occupied areas on surface, orientation angles and so on, it can be concluded that with the increase of inhibitor concentration, inhibitor molecules could form a dense and ordered self-assembly film on metal surface, and when the concentration increases to a critical value, one kind of micelle would form in solution.With the increase of alkyl chain length of inhibitor molecules, the inhibition efficiency will be improved largely, but when the length increases to a critical value, the inhibition efficiency will keep unchanged. According to the study, it can be inferred that the increase of inhibition efficiency can be ascribed to the larger adsorption energies between inhibitor films and metal surface and the increase of the thickness of the inhibitor film. Furthermore, the water wetting is studied and the results show that with the increase of chain length, the wetting angle will become bigger. Moreover, the stronger surface hydrophobicity means the better inhibition performance.Salt ion concentration has a significant influence on inhibitor configuration, and in the paper, the density distribution profiles of salt ions, compactness of inhibitor films are analyzed to rationalize the driving force promoting the conformational change of inhibitors under different salt ion concentrations. The results show that with the increase of salt ion concentration, the compactness of inhibitor film will be worse firstly, and then it will become denser, which will lead to the inhibition efficiency decreased firstly and then increase with the increase of salt ion concentration.Our researches reveal the inhibition performance under different conditions from a new aspect of adsorption behavior, and the inferred inhibition efficiency has good accordance with experimental results.