Preparation of near superlubric polysiloxane/Ti₃C₂T_x nanocomposite coating by incorporating polyalphaolefin oil microcapsules

Superlubricity, characterized by nearly vanished friction, has the great potential to significantly enhance the lubrication capabilities of self-lubricating coatings and their operational lifespan. In this work, commercial polyalphaolefin oil has been encapsulated within polystyrene shell for microcapsules synthesize, which have been further introduced into a specially designed “soft” and “hard” polysiloxane/Ti₃C₂T_x nanocomposite coating. The tribological test results show that the prepared composite coating displays a remarkable synergistic lubrication effect, achieving nearly superlow friction of 0.016 and an ultralow wear rate of 1.9 × 10⁻⁸ mm³/N·m simultaneously. The comprehensive mechanism analysis indicates that the extraordinary superlubrication effect is derived from the desirable mechanical properties of the polysiloxane/Ti₃C₂T_x nanocomposite coating and the favorable liquid lubrication effect of embedded oil microcapsules, wherein the former could enhance the conformity of surface morphology when the mating surfaces are in contact, thereby facilitating the formation of numerous microchannels; in the meanwhile, the latter could be friction-induced ruptured and then release oil molecules at the friction interface, adsorbing to the coating surface and forming an effective boundary-lubricating oil film. As a result, a remarkable synergistic lubrication effect could be created to significantly enhance the lubrication effect. It could be anticipated that this finding could expedite a broader utilization of self-lubricating coatings and superlubricity technology in the practical industrial sectors.