Solid‐state ionic conductive elastomers (ICEs) can fundamentally overcome the disadvantages of hydrogels and ionogels (their liquid components tend to leak or evaporate), and are considered to be ideal materials for flexible ionic sensors. In this study, a liquid‐free ionic polyurethane (PU) type conductive elastomer (ICE‐2) was synthesized and studied. The polyurethane (PU) type matrix with microphase separation endowed ICE‐2 with excellent mechanical versatility. The disulfide bond exchange reaction in the hard phase and intermolecular hydrogen bonds contributed to damage repairing ability. ICE‐2 exhibited good ionic conductivity (2.86 × 10‐6 S/cm), high transparency (average transmittance > 89%, 400~800 nm), excellent mechanical properties (tensile strength of 3.06 MPa, elongation at break of 1760%, and fracture energy of 14.98 kJ/m2), appreciable self‐healing ability (healing efficiency > 90%), satisfactory environmental stability, and outstanding recyclability. The sensor constructed by ICE‐2 could not only realize the perception of temperature changes, but also accurately and sensitively detect various human activities, including joint movements and micro‐expression changes. This study provides a simple and effective strategy for the development of flexible and soft ionic conductors for sensors and human‐machine interfaces.

Self-healable and stretchable elastomeric material is essential for the development of flexible electronics devices to ensure their stable performance. In this study, a strain sensor (PIH 2 T 1 -tri/CNT-3) composed of self-repairable crosslinked elastomer substrate (PIH 2 T 1 -tri, containing multiple reversible repairing sites such as disulfide, imine, and hydrogen bonds) and conductive layer (carbon nanotube, CNT) was prepared. The PIH 2 T 1 -tri elastomer had excellent self-healing ability (healing efficiency = 91 %). It exhibited good mechanical integrity in terms of elongation at break (672 %), tensile strength (1.41 MPa). The Young's modulus (0.39 MPa) was close to that of human skin. The PIH 2 T 1 -tri/CNT-3 sensor also demonstrated an effective self-healing function for electrical conduction and sensing property. Meanwhile, it had high sensitivity (gauge factor (GF) = 24.1), short response time (120 ms), and long-term durability (4000 cycles). This study offers a novel self-healable elastomer platform with carbon based conductive components to develop flexible strain sensors towards high performance soft electronics.

No abstract