Photothermally responsive and durable polydopamine-modified MXene-PNIPAM hydrogels for smart friction regulation

In this study, a polydopamine (PDA)-modified MXene-PNIPAM (pMP) hydrogel is prepared using a soap-free emulsion polymerization method, which shows enhanced anti-oxidative, photo-thermal, and tribological properties. The introduction of PDA not only inhibits the oxidation of MXene but also enhances the photo-thermal conversion efficiency of the hydrogel. Even after 50 days, it can still maintain good photo-thermal conversion performance. Moreover, compared with PNIPAM hydrogel, the friction coefficient (COF) and wear volume of pMP hydrogel as lubricant were reduced by 33% and 85%, respectively. Interestingly, the control of COF with excellent reversibility and durability is achieved using pMP hydrogel modulated by near-infrared light. The pMP composite hydrogel exhibits promising prospects in the fields of intelligent robots and biomedical devices. [Display omitted] •pMP hydrogel with excellent photothermal conversion performance was designed and prepared.•Polydopamine can significantly enhance the oxidation resistance of pMP hydrogel.•pMP exhibits reversible NIR light active modulation capabilities for friction control.•The method and materials developed in this work have broad application prospects in smart materials and intelligent devices.