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

Application of MXene-polymer composites in 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 direct light printing (DLP) of 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 and sub-microradian stability of these electromechanical sensors demonstrates their suitability for applications such as high precision 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.