Wet-spinning of ionic liquid@elastomer coaxial fibers with high stretchability and wide temperature resistance for strain sensors

Abstract

Integration of high wearing comfort, excellent conductivity and superior stretchability is required for wearable strain sensors. The construction of ionic conductors into elastic fibers and woven cloths can simultaneously realize wearing comfort and high elasticity. However, the fabrication of ionic conductive fibers with mechanical elasticity and high conductivity for fibrous strain sensors is challenging. Herein, a wet-spun encapsulation strategy is proposed for preparing a highly stretchable and fatigue-resistant ionic conductive fiber with a unique coaxial structure of ionic liquid core and thermoplastic elastomer sheath (IL@TPE). Particularly, the IL@TPE fiber exhibited a high stretchability of >250% and excellent ionic conductivity under a wide temperature range of −50 to 50 °C and long-term storage of >6 months. The as-assembled IL@TPE fibrous strain sensor exhibited excellent stability of >3000 cycles, low hysteresis, fast response time and high linearity for detecting human motions. The wet-spun encapsulation strategy for the fabrication of coaxial ionic fibers holds great promises for applications in smart wearable sensors with large stretchability, wide temperature resistance and high linearity.