Manipulating the structure of covalent organic frameworks through p-π resonance toward excellent tribological properties

Covalent organic frameworks (COFs), as a well-known carbon-based material, exhibit multiple morphologies due to their controllable structure units. In this study, we proposed a molecular engineering approach utilizing the methoxy group to adjust the p -π resonance and synthesized two distinct covalent organic frameworks (COFs), designated as TATP (without methoxy) and TADM (with methoxy). These COFs exhibit significant morphological and structural disparities; TATP adopts a spherical morphology, whereas TADM forms layered structures with a high aspect ratio. The incorporation of TADM led to an excellent reduction in wear rates by 78.93 % compared to TATP (37.31 %). The exceptional interfacial lubrication performance of TADM is attributable to not only the successfully manipulated high-oriented layer structure through p -π resonance but also the formation of Fe–N bonds between the electron-rich nitrogen atoms in TADM and the electron-deficient iron atoms during the friction process.