A Flexible Pressure Sensor Based on Composite Piezoresistive Layer

Abstract

With the rapid development of the flexible electronics field, flexible pressure sensors are widely used in wearable devices, medical monitoring and other fields. However, it is still a huge challenge to design a sensor with high sensitivity, low cost and a simple manufacturing process. In this paper, a resistive pressure sensor based on a composite conductive layer is developed. The polydimethylsiloxane (PDMS) is used as the matrix of the composite. The electrolyte fully absorbed by the super absorbent polymer (SAP ⁺ ) and used as the conductive filler of the composite. The elastic polymer is used to replace the common rigid conductive fillers (such as carbon nanotubes, graphene, etc.), can be better combined with the matrix, greatly improving the stability and reducing the Young's modulus of the sensor. After describing the working mechanism of the sensor, the influence of the composite conductive layer of different thicknesses and the content of SAP ⁺ on the electrical output of the sensor is discussed. In addition, the sensor exhibits high sensitivity (0.062 kPa ⁻¹ ), a fast response time (0.136 s) and excellent cyclic loading/unloading stability (>500 cycles).