Achieving maintenance-free durability of PI composite coatings through a hard-soft cross-scale synergistic structure

Carbon fibers were functionalized by metal-organic frameworks (MOFs), referred to as MCFs, through chemical self-polymerization and solvothermal reactions, and then combined with polytetrafluoroethylene (PTFE) to construct a hard-soft cross-scale synergistic structure, resulting in the preparation of polyimide (PI) composite coatings. Tribological tests were conducted under different conditions, after which the fundamental role of MCFs and PTFE in modifying the friction-reduction and anti-wear performance of PI was discussed based on in-depth characterization of the composite coatings' worn surface and transfer films formed on the counter steel surface. It was revealed that the MCFs/15PT/PI composite coating exhibited excellent tribological properties, which also exhibited high friction stability and wear resistance across varying loads and sliding speeds. Additionally, the composite coating was found to be potentially applicable for maintenance-free applications due to its excellent long-term tribological performance.