A boost lubrication performance of reduced graphene oxide synergizing with carbonized polymer dots via tribochemistry

Reduced graphene oxide (rGO) can become a new generation of lubricating materials because of its unique physicochemical properties. However, the aggregation phenomenon of rGO in base oils remains a significant bottleneck for its sustainable and industrial applications. To address this issue, we developed a strategy to enhance the lubricating properties of rGO using carbonized polymer dots (CPDs) assisted by the dispersant Span 80 (SP). This study demonstrated the effectiveness of this approach using various analytical techniques. Experimental data showed that the prepared CPD/rGO/SP nanofluid exhibited significant dispersion stability in sedimentation tests. From a macroscopic tribological viewpoint, the CPD/rGO/SP nanofluid exhibited excellent friction reduction and antiwear properties. Compared with the base oil, its average friction coefficient and wear scar diameter were reduced by 33.1 % and 39.8 %, respectively. Further experiments also revealed that the nanofluid exhibited efficient lubrication characteristics under certain loads, certain rotational speeds, and prolonged lubrication conditions. Mechanism analysis indicated that the interfacial interaction between CPDs and rGO produced a significant synergistic effect, which provided the conditions for the formation of a continuous and dense tribofilm, effectively isolating frictional mating surfaces, and achieving efficient lubrication. Therefore, this study presents a simple and universal solution to address the key issue of rGO in oil-based lubrication, laying the foundation for its large-scale industrial production.