Hierarchically Structured Self-Healing Sensors with Tunable Positive/Negative Piezoresistivity

It is a challenge to manufacture flexible sensors that possess easily distinguishable biomotion signals, strong response reliability, and excellent self-healing capability. Herein, a self-healing sensor with tunable positive/negative piezoresistivity is designed by the construction of hierarchical structure connected through supramolecular metal-ligand coordination bonds. The developed sensors can be integrated with the human body to detect multiple tiny signals, such as pronunciation, coughing, and deep breathing. Interestingly, the nanostructured elastomer sensor with and without a flexible yarn electrode shows negative and positive current signals, respectively, making it easy to be identify. Furthermore, it exhibits very fast (2 min), autonomous, and repeatable self-healing ability with high-healing efficiency (88.6% after the third healing process). The healed samples still possess flexibility, high sensitivity, and accurate detection capability, even after bending over 10 000 cycles. The excellent biomimetic self-healing performance combined with the tunable piezoresistivity make it promising for next-generation wearable electronics.