Highly Sensitive Piezoresistive Pressure Sensor Based on Micropyramid Patterned Tough Hydrogel

Abstract

Hydrogel-based piezoresistive pressure sensors hold enormous potential in flexible electronics. However, limited bulk resistance variation inside the hydrogels strongly hinders their practical applications for flexible electronics. Herein, we prepared a type of piezoresistive pressure sensor by decorating pyramid microarrays on surface of a tough polyacrylamide (PAAm)/poly(vinyl alcohol) (PVA) hydrogel. To achieve high sensing behaviors, sizes and topologies of the recessed pyramid microarrays molded by three-dimensional (3D) printing photosensitive resin were carefully investigated for elaborate fabrication of pyramid microarray hydrogel. The PAAm/PVA hydrogel of excellent comprehensive mechanical performances decorated with pyramid microarrays was able to generate large contact resistance variation to response external pressure, achieving a high sensitivity up to 2.27 kPa -1 . Such tough and sensitive hydrogel-based flexible sensors have significant potential applications in the fields of underwater acoustic detection, E-skins, and wearable devices.

Keywords: Pyramid microarray hydrogel, Surface modification, Piezoresistive pressure sensor, Large contact resistance variation, high sensitivity