Semi-embedded robust MXene/AgNW sensor with self-healing, high sensitivity and a wide range for motion detection

Flexible sensors are attracting tremendous interest in electronic skins and human detection. It is highly desirable yet challenging to incorporate self-healing, high sensitivity, and large stretchability into strain sensors due to their internal contradiction and complex manufacturing process. Herein, we fabricate such a sensor with a unique multiscale conductive layer structure by simply spraying conductive substances to the elastomer with dynamic Diels-Alder (DA) bonds. The multiscale structure consists of 1D semi-embedded silver nanowire (AgNW) and 2D transition metal carbide/carbonitride (MXene) nanosheets. Meanwhile, the AgNW does not merely provide stable conductivity as well as a robust interface bonding with the substrate under considerable strain. While MXene is tightly coated on the AgNW skeleton, the intrinsic brittleness of MXene supports a significant resistance variation when stretching. The obtained sensor can simultaneously achieve highly sensitive, a wide sensitivity range (0.5%∼ 96%), excellent durability, fast response (71 ± 4.9 ms), and relaxation (138 ± 5.8 ms). Interestingly, it can also detect pressure over a wide range (183–2260 kPa) and even withstand human walking and hand touching. Moreover, benefiting from the dynamic and designability crosslink network, the mechanical and electrical properties can be restored. This excellent sensor provides an approach for next-generation wearable electronics.