Polypyrrole/reduced graphene aerogel film for wearable piezoresisitic sensors with high sensing performances

Wearable piezoresitive sensors have exhibited promising potentials for applications in motion detection and human-computer interactions. Herein, we reported a facile sol-gel followed by hydrothermal reduction approach to prepare polypyrrole/reduced graphite oxide aerogel (PPy@rGA) film, which is more oriented to flexible wearable piezoresistive sensors as compared with traditional cylindrical reduced graphene oxide (rGO) aerogel. The strong π-π interactions between rGO and PPy enhance the interfacial strength and help to maintain the integrity of the composite aerogel film. Meanwhile, the PPy nanoparticles anchoring on the edges and defects of rGO sheets create more electrically conductive paths when an external pressure is applied, and therefore give rise to significant changes in the resistance value and thus excellent piezoresistive sensing performance. The PPy2@rGA film (pyrrole monomer: graphene oxide is 2:1 wt%)–based piezoresistive sensor exhibits a high sensitivity of 0.9 kPa−1 in a linear range that is of 0 to 1 kPa, a short response time of 165 ms, and a short relaxation time of 132 ms, and is able to withstand 10,000 cycles. Moreover, the wearable sensor is capable of detecting large as well as small human motion. This study shows the feasibility of fabricating wearable piezoresitive sensors from rGO aerogel films reinforced by intrinsically conductive polymers. In this polypyrrole/reduced graphite oxide aerogel film which is more oriented to flexible wearable piezoresistive sensors, PPy nanoparticles anchor adjacent rGO sheets via strong π-π interfacial forces and meanwhile serve as nano-spacers that contribute to an enhanced piezoresistive sensing performance.