3D\nDielectric Layer Enabled Highly Sensitive Capacitive\nPressure Sensors for Wearable Electronics

Abstract

Flexible\ncapacitance sensors play a key role in wearable devices,\nsoft robots, and the Internet of things (IoT). To realize these feasible\napplications, subtle pressure detection under various conditions is\nrequired, and it is often limited by low sensitivity. Herein, we demonstrate\na capacitive touch sensor with excellent sensing capabilities enabled\nby a three-dimensional (3D) network dielectric layer, combining a\nnatural viscoelastic property material of thermoplastic polyurethane\n(TPU) nanofibers wrapped with electrically conductive materials of\nAg nanowires (AgNWs). Taking advantage of the large deformation and\nthe increase of effective permittivity under the action of compression\nforce, the device has the characteristics of high sensitivity, fast\nresponse time, and low detection limit. The enhanced sensing mechanism\nof the 3D structures and the conductive filler have been discussed\nin detail. These superior functions enable us to monitor a variety\nof subtle pressure changes (pulse, airflow, and Morse code). By detecting\nthe pressure of fingers, a smart piano glove integrated with 10 circuits\nof finger joints is made, which realizes the real-time performance\nof the piano and provides the possibility for the application of intelligent\nwearable electronic products such as virtual reality and human–machine\ninterface in the future.