MXene-Based Dual Network Hydrogel as Flexible Strain Sensor for Human Actions Recognition

Conductive hydrogels for smart wearable devices have attracted increasing attention due to their excellent flexibility, versatility, and outstanding biocompatibility. In order to prepare high-performance conductive hydrogels that can be applied to strain sensing, polyacrylamide was introduced into the polyvinyl alcohol (PVA)-borax hydrogel to construct a double-network hydrogel (DNH), and Ti3C2Tx MXene and polydopamine were introduced into improve conductivity, realizing the preparation of MXene/polydopamine/PVA/polyacrylamide DNH (MXene-DNH). The effects of different mass ratios of PVA and acrylamide on the mechanical properties and electrical properties of hydrogels are systematically investigated. Among them, the MXene-DNH with the mass ratio of PVA: acrylamide =1:3.5 exhibits excellent mechanical and electrical performance, with elongation at break of 1420%, tensile strength of 249 kPa, and toughness of 1397.1 kJ/m3, electrical conductivity of 0.661 mS/cm. Moreover, the MXene-DNH can be used as strain sensor, and the sensor exhibits great sensing performance and possesses a wide strain working range (0%-965%), good sensitivity (0.38 in the 0%-100% strain range), and low hysteresis. Finally, the flexible strain sensor was applied to monitor multiple joint motions and recognize gestures, demonstrating it has broad application potential in the fields of portable wearable electronics and human-computer interaction. © 2022 IEEE.