Reductant- and stabilizer-free synthesis of graphene-polyaniline aqueous colloids for potential waterborne conductive coating application

The chemical reduction of graphene oxide (GO) typically involves highly toxic reducing agents which could contaminate and have a negative effect on the conductivity of the resulting materials. Herein we report a facile approach to prepare stable reduced graphene oxide (rGO) aqueous colloids using reduced polyaniline nanofiber (rPANI-NFs) as both a reducing and a stabilizing agent. The efficient reduction of GO is verified by infrared spectroscopy, Raman spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The adsorption of polyaniline nanofibers onto the rGO nanosheets allows a stable rGO aqueous dispersion to be formed through electrostatic stabilization. Since the rPANI-NFs could be easily doped and converted to a highly conductive material after reduction of GO, this approach provided a new method for large-scale production of aqueous rGO dispersions with great potential applications in environmentally friendly waterborne conductive coatings and construction of various graphene-based materials as demonstrated in this study of cellulose nanofiber-graphene composites.