A healable, mechanically robust and ultrastretchable ionic conductive elastomer for durably wearable sensor

The ionic conductive elastomers show great promise in multifunctional wearable electronics, but they currently suffer from liquid leakage/evaporation or mechanical compliance. Developing ionic conductive elastomers integrating non-volatility, mechanical robustness, superior ionic conductivity, and ultra-stretchability remains urgent and challenging. Here, we developed a healable, robust, and conductive elastomer via impregnating free ionic liquids (ILs) into the ILs-multigrafted poly(urethane-urea) (PUU) elastomer networks. A crucial strategy in the molecular design is that imidazolium cations are largely introduced by double-modification of PUU and centipede-like structures are obtained, which can lock the impregnated ILs through strong ionic interactions. In this system, the PUU matrix contributes outstanding mechanical properties, while the hydrogen bonds and ionic interactions endow the elastomer with self-healing ability, conductivity, as well as non-volatility and transparency. The fabricated ionic conductive elastomers show good conductivity (3.8 × 10−6 S·cm−1), high mechanical properties, including tensile stress (4.64 MPa), elongation (1470%), and excellent healing ability (repairing efficiency of 90% after healing at room temperature for 12 h). Significantly, the conductive elastomers have excellent antifatigue properties, and demonstrate a highly reproducible response after 1000 uninterrupted extension-release cycles. This work provides a promising strategy to prepare ionic conductive elastomers with excellent mechanical properties and stable sensing capacity, and further promote the development of mechanically adaptable intelligent sensors.