Despite considerable advances in the development of waterborne polyurethane (WPU) with strength, toughness, or room-temperature self-healable properties, integrating all these features into a single material is a formidable challenge. Herein, we employ 1,8-menthane diamine (MD) as a post-chain extender to fabricate a WPU material rich in multiple urea hydrogen bonds. The resulting WPU/MD-3 film exhibits outstanding mechanical performances, including a tensile strength of 33.74 MPa, a fracture strain of 1086%, and a remarkable toughness of 139.58 MJ/m 3 . Moreover, it shows rapid self-healing at room temperature when exposed to trace ethanol, reaching a high self-healing efficiency of 92.3% in just 6 h. These performances surpass those of the majority of previously documented self-healable polymers at room temperature (healing efficiency ≥ 80%). Surprisingly, WPU/MD-3 film exhibits cyan-green fluorescence under ultraviolet (UV) light due to cluster-triggered emission (CTE) effect, and demonstrates potential applications in anti-counterfeiting, information encryption, and crack diagnosis. Overall, this work offers new insights for designing multifunctional WPU that combine superior mechanical properties with efficient room-temperature self-healing ability.
Li et al. (2026) studied this question.