Simultaneously Achieving High Strength, High T g , and Self‐Healing in Polyurethane Elastomers via Dual Dynamic Non‐Covalent Bonds and Self‐Assembled Fiber‐Like Structures

We synthesized polyurethane elastomers with dual dynamic non‐covalent bonds and self‐assembled polyphenylene ether (PPO) fiber‐like structures. The findings reveal that the increased PPO chains can assemble into fiber‐like structures, which can intertwine densely owing to π‐π interactions between the rigid benzene rings. The resultant elastomers possess outstanding mechanical properties including high tensile strength of 19–62 MPa, elongation at break of 248%–1186% and toughness up to 80–113 MJ/m 3 . Moreover, the elastomers display high glass transition temperature (T g ) of ~95°C. The self‐assembled PPO chains can contribute to the good mechanical stability of the elastomers even at 100°C. The combined effects of dynamic hydrogen bonds and π‐π interactions endow the elastomers with excellent self‐healing and reprocessing abilities. The self‐healing efficiency of tensile strength for the elastomers can reach up to 58%–153% after heating at 140°C for 2 h, and the tensile strength of the remolded elastomers can recover up to 31%–90% of the original values. Owing to the significant phase‐separated structures, the elastomers have excellent shape memory properties. The calculated shape fixation and recovery rates of the elastomers are 78%–81% and 75%–98%, respectively. The flexible sensors based on the elastomers can be used as motion wearable sensors and thermally controlled switches.