A flexible and highly pressure-sensitive PDMS sponge based on silver nanoparticles decorated reduced graphene oxide composite

Abstract

Flexible pressure sensors have a wide range of applications in wearable electronics and human-machine interfacing. A flexible and highly pressure-sensitive sensor was fabricated with silver nanoparticles (Ag NPs) decorated-reduced graphene oxide composites (Ag/rGO) filling into the PDMS sponge. The Ag/rGO composites were synthesized by one-step chemical reduction method that Ag NPs were tightly and uniformly coated on the surface of reduced graphene oxide nanosheets. Then Ag/rGO composites filled PDMS sponge (Ag/rGO-PDMS) was prepared through a dip-drying method as pressure sensitive materials. The Ag NPs coated on the surface of graphene nanosheets improved the conductivity of the Ag/rGO composites and reduced the contact resistance of graphene nanosheets. The graphene nanosheets could enhance the flexible stability and facilitate the electron transport in Ag/rGO-PDMS. The Ag/rGO-PDMS sponge with optimized GO to Ag weight ratio showed maximum pressure sensitivity of 8.86 kPa−1 which enhanced twenty-two times compared with that of pure rGO filled PDMS sponge (0.40 kPa−1). The flexible Ag/rGO-PDMS sponge with high pressure sensitivity could be used for detection of different kinds of mechanical forces (pressing, bending and twisting) and radial artery blood pulses in real-time.