Synthesis of water soluble graphene

A facile and scalable preparation of aqueous solutions of isolated, sparingly sulfonated graphene is reported. C-13 NMR and FTIR spectra indicate that the bulk of the oxygen-containing functional groups was removed from graphene oxide. The electrical conductivity of thin evaporated films of graphene (1250 S/m) relative to similarly prepared graphite (6120 S/m) implies that an extended conjugated Sp(2) network is restored in the water soluble graphene.