Facile Preparation of MXene/Poly(vinyl alcohol)/N-(2-Hydroxyethyl Acrylamide) Hydrogels with High Tensile Strength for Strain Sensors

In this paper, a novel conductive hydrogel was made by a one-pot method at 60 °C for 12 hours in one step without any cross-linking agent. The hydrogel was composited of Ti3C2 MXene nano slices, poly(vinyl alcohol) (PVA) and poly-N-(2-hydroxyethyl acrylamide) (PHEAA), named as MXene/PVA/PHEAA hydrogel. Compared with previous methods to make MXene hydrogel, this one-pot method was facile and fast. The as-prepared hydrogel was highly stretchable with the breaking elongation of 1300% and tensile strength of 1.1 MPa. MXene nano sheets dispersed in the hydrogel formed a three-dimensional conductive network, which increased the strength and conductivity of the gels. The conductivity changed with the gel’s deformation and could be applied as strain sensors. The strain sensors made of the hydrogels were highly stretchable, bendable and flexible with the response range of 1%–300% and a large gauge factor of 4.23. The sensors can be applied to detect human movements such as finger bending, leg bending, water drinking. The MXene/PVA/PHEAA hydrogel made by this facile one-pot method is promising to make strain sensors for health detection.