3D Dielectric Layer Enabled Highly Sensitive Capacitive Pressure Sensors for Wearable Electronics

Abstract

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