Conductive MXene nanocomposite organohydrogels for ultra-stretchable, low-temperature resistant and stable strain sensors

Abstract

Hydrogels have unique flexibility and a highly efficient, low-cost manufacturing process, thus they are expected to be used in electronic skin, wearable sensors, soft robotics, and human–computer interaction. However, the application of conductive hydrogels in monitoring large deformations is severely limited by their low mechanical properties and inability to work at low temperature. In this study, MXene/PAM/CMC-Na (MPCE) hydrogel was immersed in a mixed EG/H₂O solution to improve the overall performance of the hydrogel, and the dual action of EG and N,N-dimethylformamide in the MXene organic dispersion enhanced its anti-freeze properties. Furthermore, MXene nanosheets can be hydrogen bonded to the entangled polymer network structure, significantly improving the mechanical properties of the MPCE hydrogel. The hydrogel had extremely tensile strength (5023% tensile strain) and excellent freezing resistance (−20 °C). These results demonstrated that the MPCE hydrogel could accurately monitor minute human movements, such as finger flexion, wrist and elbow action, muscle vibration, and eyelid blinking. It can be used as a strain sensor to provide real-time feedback on human movements.