Intelligent NIR-responsive Ti₃C₂T_x MXene films for on-demand dynamic friction modulation and sustainable robust...

The tunable surface chemistry, weak interlayer forces, and superior interfacial sliding properties endow Ti₃C₂T_x MXene with great promise in lubrication. However, its responsive and dynamic regulation over friction remain an unaddressed challenge. Herein, our work develops a pressure-induced strategy to prepare thin Ti₃C₂T_x MXene nanosheets, and constructs various solid-liquid lubricating systems with tunable structure for robust long-time and responsive lubrication. To build the system, thin Ti₃C₂T_x MXene nanosheets with good crystal structure is prepared by an acid pre-soaking and high-pressure deep exfoliation method. The nanosheets are orderly deposited onto substrates to form a dense, smooth and thickness-controllable film, and then various lubricating oils are absorbed into the film to construct different solid-liquid interfaces. Ultra-low friction under various working conditions is obtained, and a lowest friction coefficient of 0.025 is achieved, representing a significant 95.8 % reduction compared to the pure substrate. Moreover, the systems endure over 14,400 friction cycles without any signs of lubrication fluctuations or failures, showcasing outstanding sustainable stability. Notably, upon near-infrared light irradiation, the interfaces undergo rapid reorganization, shortening the break-in period to a mere 44 s and further reducing friction. This work elucidates the synergistic effect of Ti₃C₂T_x MXene with lubricants, providing a reliable strategy for achieving adaptive lubrication in complex environments.