In-situ reduction of graphene oxide-wrapped porous polyurethane scaffolds: Synergistic enhancement of mechanical properties and piezoresistivity

Lightweight conductive graphene@polyurethane (PU) sponge with unique 3D structure and prominent piezoresistivity is a promising candidate for highly sensitive pressure sensor. However, the poor mechanical properties of PU skeleton and the use of toxic reductant for the reduction of graphene oxide (GO) greatly hampered its large-scale application. Here, we demonstrated for the first time that aramid nanofibers (ANFs) can be used as desirable building blocks to endow the layer-by-layer (LBL) assembled GO@PU nanocomposites with excellent mechanical properties. At the same time, the potassium hydroxide existed in ANFs solution could in-situ reduce the GO without extra reductants. The as-prepared rGO@PU/ANFs conductive nanocomposites exhibited excellent piezoresistive sensitivity and repeatability, enabling the nanocomposites to serve as flexible sensors for the application of human motions monitoring. This work opens up new opportunity for the facile fabrication of high performance graphene-based piezoresistive sensors and other electronic devices.