Graphene Nanosheets Modified with Diamines and C60 for Applications in Lubricating Oil

Research into the synergistic lubrication effects of graphene oxide (GO) and fullerene (C60) is limited to basic mechanical mixing methods. This research introduces a design strategy for composite nanomaterials with sandwich structures. By reacting single-layer GO with amines (1,6-hexanediamine (HMD), 1,8-octanediamine (DAD), 1,10-decanediamine (DAO), 1,12-dodecanediamine (DDA)), the single-layer structure is converted into a multilayer structure. C60 is simultaneously introduced during synthesis, resulting in an oil-soluble nanolubricating additive (GO–R/C60, R = HMD, DAD, DAO, DDA) with remarkable antiwear capabilities. The influence of diamine chain length on the capture and release of C60 and its tribological properties was investigated through dispersion experiments, tribological tests, and molecular dynamics simulations. The GO–DDA/C60 demonstrates outstanding antiwear performance under high contact stress (1.42 GPa), reducing the friction coefficient and wear cross-sectional area by 30% and 98%, respectively. The results indicate that the sandwich structure nanocomposite material significantly enhances the antiwear performance of lubricating oils by suppressing wrinkling at the edges of GO, releasing C60 under stress and shear, good interfacial adsorption performance, and a synergistic antiwear effect between GO and C60.