Transparent, Mechanically Robust, Low-temperature- tolerance, and Stretchable Ionogels Enhanced by Konjac Glucomannan toward Wireless Strain Sensors

Abstract

Electronic skins (E-skins) are capable of detecting human health and movement, which has promising potential in the fields of human-machine interactions and artificial intelligence. However, traditional hydrogels-based E-skins suffer from poor mechanical strength, low conductivity, and instability owing to the evaporation of water. Herein, to advance the unsatisfaction of E-skins above, a semi-interpenetrating network developed by polysaccharide biomass konjac glucomannan (KGM) was introduced into covalent-crosslinked network (PAA-co-PAM) to synthesize a transparent, tough, nonvolatile, and highly stretchable ionogel with an ionic liquid (EMIM:DCA) as conductive media. This ionogel exhibited extraordinary mechanical strength (tensile strength 2.77 MPa), outstanding mechanically durability (100 stretching cycles of 250%) and elongation (elongation at break 997%). More importantly, the ionogel demonstrated remarkable anti-freezing performance (high flexibility at -20℃) and high conductivity (3.94 mS/cm) in the absence of water. Besides, after assembly from konjac glucomannan-enhanced ionogel, the sensor exhibited comprehensive strain sensing performance, which could effectively and accurately monitor the human motion via Bluetooth transmission. This strategy paves the way for a viable new generation of multifunctional biomimetic super-sensitive sensors, which have great promise for applications such as intelligent devices, health detection, and biomedical monitoring in harsh conditions.