Bioinspired Self‐Healing Polyurethane‐Based Ionogel for Dual‐Modal Strain Sensing and Solvent‐Triggered Alerting

ABSTRACT Current polyurethane/ionic liquid (PU/IL) sensors are predominantly restricted to single physical sensing, as well as have great challenge in balancing the mechanical robustness and conductivity. Inspired by the swelling‐enhanced ion migration behavior of plant cell walls, a novel bio‐mimetic polyurethane‐based ionogel (HPU‐IL) was designed, which integrates a hindered urea bond‐crosslinked polyurethane skeleton with [BMIM][TFSI] ionic liquid by hydrogen bonds and electrostatic interactions. This unique structure exhibits excellent conductivity and solvent‐induced swelling, achieving the dual‐modal sensing involving the ion migration‐driven ultra‐sensitive monitoring of solvents leakage and motion sensing. The HPU‐IL as a piezoresistive sensor is capable of accurately capturing human motion signals due to deformation‐induced effect. Once contacting solvents, the rapid swelling of HPU‐IL matrix will expand the nanoscale channels, further accelerating the ion migration and resistance change. This special mechanism that is distinct from traditional sensing pathways triggers a sharp resistance decrease (2 s) and activates the alarms within 15–30 s. The HPU‐IL ionogel demonstrates exceptional elasticity and robustness (805% of elongation, 1.32 MPa), high conductivity (8.3×10 −4 S cm −1 ) and 95% self‐healing efficiency, while exhibiting recyclability and antibacterial properties. This work offers a new idea for the design of multifunctional flexible wearable sensor, showing great potential application in practical scenarios.