Synergistic Hydrogen Bonding Topology Enables Ultra-Robust Polyurethane Elastomers for Multifunctional Strain Sensors

Herein, a dynamic multilevel hydrogen bonding strategy is proposed, and a polyurethane elastomer with high strength, high toughness, and efficient self-healing properties is successfully synthesized. By constructing a gradient hydrogen-bonding topology comprising both strong (urea-based) and weak (ester-based) hydrogen bonds, a hierarchically cross-linked network is established, effectively mitigating the conventional trade-off between mechanical strength and toughness in polyurethanes. The optimized polyurethane exhibits a tensile strength of 41.6 MPa and outstanding toughness (109.9 MJ·m–3), outperforming most reported polyurethane elastomers. The weak hydrogen bonds enable rapid self-healing (89% recovery after 2 h at 80 °C), while the strong ones contribute to structural integrity. Furthermore, the incorporation of an ionic liquid imparts good electrical conductivity to the material, allowing real-time monitoring of human joint movement and demonstrating potential in health monitoring and flexible sensing applications. This work provides a approach for constructing mechanically adaptive polymers based on a dynamic multilevel hydrogen bonding strategy, advancing the development of high-performance flexible electronic materials.