Self-healing flexible strain sensors based on dynamically cross-linked conductive nanocomposites

Self-healing, flexible, robust and adaptable strain sensors with intelligent skin-like features are greatly promising for future wearable devices. In this work, we demonstrate a self-healing flexible strain sensor with stretchability, robust mechanical strength, and high sensing sensitivity, which can monitor human motions. The sensor is constructed by the dynamically cross-linked conductive nanocomposite based on imine and quadruple hydrogen bonds. Due to the reversible interactions, the nanocomposites exhibit excellent self-healing performances with the healing efficiency up to 95%. The interfacial compatibility between the nanofillers and polymer networks is enhanced through the supramolecular interactions. Based on piezoresistive effects, the change of resistance for the nanocomposite-based strain sensor can be obviously observed under various deformation including stretching, bending, and twisting. Meanwhile, the gauge factor of the sensor reaches 46, showing high sensing sensitivity. Benefited from the self-healing feature, the sensor can withstand mechanical damage and restore the function of detecting human motions, enabling reliability and stability in practical applications, which shows great potential for developing smart wearable devices, healthcare monitoring, and human-machine interfaces.