Covalent organic framework/graphene oxide hybrids via in situ polymerization as high-performance lubricant additives

Covalent organic frameworks/graphene oxide (COFs/GO) hybrid nanocomposites were synthesized via an in-situ polymerization strategy and evaluated as lubricant additives in polyalphaolefin (PAO 10) under severe operating conditions. Two hybrids, TATP/GO and TADM/GO, were prepared and their tribological performance was systematically investigated. Structural characterization revealed that the in situ growth of TADM increased the interlayer spacing of GO and improved its dispersion behavior in PAO 10. At the optimal concentration of 0.05 wt.%, TADM/GO reduced the friction coefficient and wear volume by 30.43% and 95.58%, respectively, compared with neat PAO 10 in reciprocating sliding tests. Under four-ball conditions with an applied load of 392 N, TADM/GO maintained effective lubrication for 4 h, reducing the friction coefficient and wear volume by 35.71% and 69.37%, respectively. The wear volume after 4 h is only 47.54% higher than that measured in the independent 1 h test, demonstrating sustained anti-wear performance under prolonged severe contact conditions. The superior tribological performance of TADM/GO is attributed to the synergistic effects of surface filling, interlayer sliding, and tribochemical film formation. Raman analysis of the worn surface further revealed improved retention of the conjugated carbon structure in the TADM/GO-derived tribofilm under severe shear. These findings demonstrate the potential of molecularly engineered COF/GO hybrids as lubricant additives for severe contact conditions.