Flexible and Electrically Conductive 3D-Printed Ti3C2Tx MXene–Hydrogel Copolymers for the High-Precision Sensing of Biomechanical Processes

The application of MXene–polymer composites to wearable and implantable medical devices requires the development of hydrophilic and biocompatible MXene–polymer hydrogel composites with high electromechanical response, flexibility, and durability. Here, we formulate low weight percentage MXene–hydrogel copolymer inks enabling the direct light processing (DLP) of Ti3C2Tx MXene–polyvinyl alcohol (PVA)–polyacrylic acid (PAA)–hydrogel composites. The low wt% MXene–PVA–PAA composites demonstrate high biocompatibility, mechanical flexibility, high sensitivity and high precision for sensing acute bending angles. The sub-millidegree angle resolution of these electromechanical sensors demonstrates their suitability for applications such as the highly precise tracking of joint movements. In addition, the synthesized MXene membranes show promise for applications in osmotic energy conversion, with a harvested electric power density of 6.79 Wm−2.