Polymeric Ionic Liquid-Ti₃C₂T_x MXene Hybrid Additives for Enhanced Lubrication of Ethylene Glycol/Water Systems

Ethylene glycol/water (EG/W) systems are prevalently employed in hydraulic systems and metal processing, attributed to their superior flame retardancy and environmental friendliness. However, its weak lubrication performance poses challenges in fulfilling the requirements of advanced equipment and manufacturing. Utilizing the synergistic effect between two-dimensional nanomaterials (Ti₃C₂T_x MXene) and polymer ionic liquids (PILs) to construct a stable lubricating film provides a potential solution to this problem. This study successfully synthesized Ti₃C₂T_x nanosheets and PIL, using them as lubricant additives in the EG/W system. The findings reveal that the PIL-MXene hybrid additive exhibits excellent dispersion stability, enhancing the wettability on steel substrates and anticorrosion performance of the EG/W system. Tribological experiments demonstrate that the introduction of an optimal quantity of PIL-MXene (3 wt % PIL and 50 μg mL^-1 MXene) reduces the average friction coefficient and wear scar diameter of the EG/W system by 74.6 and 35.38%, respectively, to 0.032 and 0.42 mm. This improvement is credited to the synergistic tribological effect between PIL and Ti₃C₂T_x nanosheets along with the formation of composite tribo-films. In comparison to single additive (PIL or MXene), the formation of continuous and enhanced protective layer is the main reason why the PIL-MXene hybrid additive provides the durable and stable lubricating performance. This organic-inorganic hybrid strategy not only proposes a solution to the inadequate lubrication of the EG/W system but also offers a theoretical reference for the functional application of two-dimensional materials in complex fluid systems.