Piezoresistive flexible pressure sensor using vuggy clays as templates

With the rapid development of the wearable electronics, the flexible mechanical sensors have drawn much attention. However, the sensors have encountered problems such as high cost, complex process structure and low sensitivity, which limit their practical application. In this paper, we fabricate a flexible piezoresistive sensor with a double-layer micro-convex structure using a simple, and low-cost PDMS inverted template technology based on a simple vuggy clay template. The sensor exhibits a high sensitivity of 0.78 kPa(-1) at low pressure (< 200 Pa), with fast response time (< 100 ms), high stability in 1000 pressure loading/unloading cycles, low pressure detection limit of 1 Pa, and a wide operating pressure range (< 20 kPa). The developed flexible pressure sensor has been successfully used to detect human radial artery and respiratory conditions, showing broad prospects in monitoring human movement and great application potential in wearable devices.