One‐step preparation of highly conductive eutectogel for a flexible strain sensor

Abstract Gels with excellent ionic conductivity and resilience to temperature extremes are sought in practical applications due to their potential for building flexible and wearable soft electronics. In this work, highly conductive eutectogels are fabricated by one‐step polymerization of (3‐acrylamidopropyl) trimethyl ammonium chloride in deep eutectic solvents (DESs). Owing to the ion‐conductive polymer networks facilitating ion conduction, these eutectogels exhibit a significant enhancement in ionic conductivity (27.1 mS cm−1), demonstrating an order of magnitude higher than that of pure DES. Furthermore, due to several unique properties of DES, these eutectogels exhibit excellent stretchability (>1000%), good adhesion, as well as nonflammability performance over a wide temperature range (−40 to 100°C). Moreover, the strain sensor based on the eutectogel shows a highly sensitive response (gauge factor = 6.92) to a broad strain range (from 450% to 550%), enabling the accurate and reliable detection of various human movements. Additionally, our findings reveal that the eutectogel‐based sensor displays a comparable pattern of response curves with negligible signal deterioration, even at extreme temperatures of −20 and 60°C. The results of this work will promote novel applications in the construction of flexible and safe devices.