Supramolecular gel holds great potential in engineering applications as lubricant. However, pure organic network of the gel limits their rheological and lubrication performance. Here, we report a nanoporous materials-functionalized supramolecular composite gel lubricant by incorporating polymer brush-grafted metal-organic frameworks (MOFs) nanoparticles (NPs) as nano additive. The composite gel was produced by encapsulating poly(lauryl methacrylate) (PLMA) polymer brushes functionalized UiO-67 (UiO-67@PLMA) NPs in 500 SN base oil of a 3D network formed by 12-hydroxystearic acid (12-HSA) through hydrogen bonding and van der Waals (vdW) interactions. The addition of UiO-67@PLMA NPs largely improved the thermal and rheological properties of the 12-HAS/500 SN gel, and the storage modulus and loss modulus increasing significantly. Tribological tests showed that incorporating 0.40 wt.% UiO-67@PLMA NPs into the composite gel reduced the coefficient of friction and wear volume by 45.68% and 86.85%, respectively. Furthermore, the UiO-67@PLMA gel demonstrated remarkable tribological performance under challenging conditions, such as 400 N, 65 Hz, and 160 °C. The outstanding lubrication performance of the supramolecular composite gel arises from shear-triggered release of base oil and nanoadditves, acting as nano ball-bearings and promoting protective film formation.
Qian et al. (Sun,) studied this question.