A highly sensitive and flexible capacitive pressure sensor based on a micro-arrayed polydimethylsiloxane dielectric layer

Abstract

A flexible pressure sensor with high sensitivity has been proposed which consists of a typical sandwich structure by integrating a polydimethylsiloxane (PDMS) substrate with a micro-arrayed PDMS dielectric layer. A PDMS flexible substrate coated with silver nanowires (AgNWs) is used as a top/bottom electrode material, and a PDMS dielectric layer with micro-array structure is used to ensure high sensitivity of the pressure sensor. As a result, compared with conventional parallel board capacitive sensors, such sensors exhibit good performance, high sensitivity (2.04 kPa⁻¹) in low pressure ranges (0–2000 Pa), low detection limits (<7 Pa) and fast response times (<100 ms). Furthermore, the integration of the sensor electrode and the dielectric layer ensures good bending stability and cycling stability of the sensor. Flexible capacitive pressure sensors can be used to measure the pressure distribution of finger tips when holding an object and grabbed with fingers. The spatial distribution of the applied pressure can also be clearly identified by fabricating a pressure sensor array. Due to its outstanding performance, the flexible pressure sensor shows bright application prospects in wearable sensing devices, electronic skins and humanoid robotics.