Self-Healable and Mechanically Reinforced Multidimensional-Carbon/Polyurethane Dielectric Nanocomposite Incorporates Various Functionalities for Capacitive Strain Sensor Applications

With the continuous development of wearable sensing devices utilized for human motion monitoring, structural health monitoring, and robotic systems, higher demands on a set of material properties of functional materials are placed. Moreover, high flexibility and self-healability are indispensable properties in wearable electronic devices. Herein, a self-healing flexible dielectric nanocomposite with various incorporated functionalities is described. Multidimensional carbons, that is, graphene and carbon nanotubes, are introduced into a self-healing polyurethane matrix to obtain the healable dielectric nanocomposite which contributes to the capacitance response of the wearable sensors. The as-prepared nanocomposite exhibits a dramatic increase in properties, which reach up to 10.50 +/- 0.44 MPa for Young's modulus, 35.1 for dielectric constant at 10(3) Hz, and 1.67 W m(-1) K-1 for the in-plane thermal conductivity with low loading. More importantly, the nanocomposites display a unique ability to recover the structure and multiple properties after mechanical damages. In addition, a self-healing capacitive strain sensor with the sandwich structure is prepared based on the nanocomposite. The strain sensor shows good sensitivity in a larger strain range (up to 100%), stable responsiveness, and healable ability.