Stretchable, fast response and adhesive MXene-based hydrogels for wearable strain sensor

Conductive hydrogels have emerged as significant materials within the domain of soft electronics, attributed to their remarkable stretchability, high sensitivity, and rapid response characteristics. In this study, we successfully developed a novel conductive hydrogel, named NAM, which integrates MXene nanosheets into a P(NIPAm-AAc) network to create a dynamic crosslinked structure. This NAM hydrogel exhibits exceptional mechanical properties, including a tensile strength exceeding 1400% and the ability to adhere to objects of different materials. It also demonstrates satisfactory electrical conductivity (0.233 S/m) and high sensitivity (GF=3.384), with rapid response and recovery time of 60 ms. The NAM hydrogel sensors are capable of detecting a wide range of strains (0-800%) and maintaining excellent repeatability in cyclic loading-unloading. They can effectively monitor subtle facial micro-expressions, laryngeal vocalizations, and human motion data, and can be integrated into soft robotic systems for enhanced functionality. The findings suggest significant potential applications for the NAM hydrogel in soft robotics, flexible electronic skin, smart health monitoring, and biomedicine, highlighting its multifunctional capabilities in the realm of soft electronics.