Organofluorinated Ag/2D diamond nanocomposites achieve simultaneously ultra-low friction and wear in self-lubricating epoxy

Hybrid fillers show great advantages in improving the frictional properties of epoxy (EP) composites. However, to date, achieving ultra-low coefficients of friction and wear rates in self-lubricating EP systems through the use of nanofillers remains a challenge. In this study, the hard diamond nanosheets, soft silver nanoparticles, dopamine hydrochloride, and 1H,1H,2H,2H perfluorodecyltrichlorosilane (FDTS) were designed to prepare organofluorinated Ag/2D diamond nanocomposites (NDs-fPDA-Ag NPs). The tribological tests demonstrated that 3 wt% addition of NDs-fPDA-Ag NPs in EP exhibited the best friction reduction and anti-wear properties, which were reduced by 84.3 % and 98.6 % compared with pure EP. Significantly, it stands out as the sole instance reported to date that has successfully achieved the oil lubrication (average coefficient of friction 0.085 less than 0.1) in dry friction while maintaining ultra-low wear rate (4.9 × 10 -6 mm 3 /(N·m)). The superior lubrication effect is primarily attributed to three key factors: the high hardness of the two-dimensional (2D) diamond nanosheets, which provides exceptional wear resistance; the “rolling effect” generated by the zero-dimensional (0D) silver nanoparticles, which significantly reduces the friction coefficient; and the low surface energy of outermost grafted organofluorine compounds, which minimizes interactions between the NDs-fPDA-Ag NPs and the steel friction pair. The soft and hard combination of low surface energy 2D diamond greatly enhances the tribological performance of EP composites and provides a new approach for the preparation of excellent self-lubricating epoxy systems.