Tribology and Corrosion Inhibition Properties of Dimercaptothiodizole Derivatives Based Ionic Liquids

With the development of modern high-end equipment towards extreme operating conditions (high temperature/high load/high speed) and extended service life, traditional single-functional lubricant additives face challenges in meeting complex lubrication requirements due to the antagonistic effects caused by insufficient synergy. For this reason, this study proposed the molecular functional integration strategy. Through UV-induced thiol-ene click chemistry, two multifunctional ionic liquid additives with both corrosion inhibition and friction regulation functions (P_888pMDDTf₂N and C_6vimMDDTf₂N) were successfully constructed by grafting 2,5-dimercapto-1,3,4-thiadiazole derivatives with corrosion inhibition activity onto quaternary phosphonates and imidazole type ionic liquid cations. Electrochemical tests and tribological evaluations demonstrated that both ionic liquids at 3.0% dosage reduced the friction coefficient of A51 synthetic ester oil by 17% and wear rate by 88%, while achieving corrosion inhibition efficiencies of 42.53% (P_888pMDDTf₂N) and 27.59% (C_6vimMDDTf₂N), respectively. Molecular dynamics simulations demonstrated that the higher adsorption energy of P_888pMDDTf₂N drived more intensive molecular accumulation at the tribological interface, forming a more robust adsorbed boundary layer that accounted for its enhanced lubrication performance than C_6vimMDDTf₂N. This work effectuated synergistic enhancement of lubrication and corrosion inhibition through molecular structural design, providing a novel approach for developing multifunctional lubricant additives.