Conductive Hydrogel with Ta4C3TX MXene to Detect Human Movement

Abstract

Nanocomposite hydrogels with exceptional mechanical properties and sensing performance are ideal for flexible sensors designed to detect human movements and monitor human health. In this study, a composite hydrogel was prepared through in situ polymerization using a combination of poly(methacrylic acid-co-acrylamide) (P(MAA-co-AAM)), poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS), and Ta₄C₃T_X MXene. The resulting P(MAA-co-AAM)/PEDOT/PSS/Ta₄C₃T_X hydrogel features a porous network structure closely cross-linked with hydrogen bonds, providing superior mechanical properties such as high elastic modulus, compressive strength, and low hysteresis ratio. The compressive strength of the hydrogel reaches 386.80 kPa, significantly surpassing that of pure P(MAA-co-AAM) hydrogels and other hydrogels. The piezoresistive sensor developed with this hydrogel demonstrates outstanding pressure sensing capabilities: a sensitivity of 0.44 kPa^–1, a low detection limit of 38.63 Pa, a rapid response time of 44 ms, and a recovery time of 58 ms. Notably, the sensor can sustain over 1000 sensing cycles with remarkable stability and weather resistance. It can accurately detect human body movements, such as joint movements, and even recognize subtle facial microexpressions. Furthermore, the sensor can wirelessly monitor robotic movements through a Bluetooth system and accompanying software. This mechanically robust hydrogel holds significant promise for applications in pressure sensors, human-machine interaction, and portable wearable devices.