Dynamic self-healing (N,B,P) co-doped carbonized polymer dots as lubricant additives for enhanced lubrication performance

Lubricant additives have been widely applied in industrial applications; however, achieving efficient wear repair and long-term lubrication in mechanical systems remains a significant challenge. Herein, a nitrogen, boron, and phosphorus co-doped carbonized polymer dots (CPDs-200) was designed and synthesized, combining the unique properties of nanomaterials and polymers to deliver remarkable self-healing capabilities and lubrication performance. By precisely controlling the reaction temperature, the surface structure and conjugation degree of CPDs-200 were optimized to investigate its tribological behavior. The results demonstrated that CPDs-200 exhibited good dispersion stability in PEG200, maintaining stability for over 9 months, even at high concentrations. A systematic evaluation of its tribological performance at different stages revealed that CPDs-200 significantly outperformed PEG200 alone, decreasing the average friction coefficient to 0.051 and wear volume by 78 %. Notably, the wear volume exhibited a decrease after 15 min of operation, indicating its dynamic repair capability. Density Functional Theory calculations and Molecular Dynamics simulations were used to analyze the adsorption behavior and tribochemical reactivity of CPDs-200, revealing its underlying lubrication mechanism at the microscopic level. In combination with XPS analysis, the formation of complex tribochemical interactions between the material and the frictional substrates was confirmed. CPDs-200 rapidly infiltrated the frictional interface, effectively repairing microcracks and surface grooves, and subsequently formed a robust tribochemical reaction film, thereby achieving long-lasting lubrication and significantly improving wear resistance.