Sensitive piezoresistive pressure sensor based on micropyramid patterned tough hydrogel

Microstructures are decisive factors of hydrogel-based piezoresistive pressure sensors for excellent performances in flexible electronics. However, the desirable microstructures are still difficult to be completely engineered on the surface of hydrogel, owing to limitations concerning to comprehensive mechanical performances of hydrogels. Herein, we prepared a type of piezoresistive pressure sensor by decorating pyramid microarrays on the surface of a tough and ionically conductive 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 investigated for elaborate fabrication of pyramid microarray hydrogel. The ionically conductive PAAm/PVA hydrogel of excellent comprehensive mechanical performances decorated with pyramid microarrays was able to generate large contact resistance variation to respond to external pressure, achieving a maximum sensitivity to 2.27 kPa−1, low detection limit of 9.0 Pa, as well as good recoverability and stability. Such tough and sensitive device based on micropyramid patterned tough hydrogel have potential applications in the fields of flexible electronics.