Chemical modification of graphene oxide through poly(ethylene oxide)-conjugations

Abstract

This paper introduces poly(ethylene oxide) (PEO)-based modification of graphene oxide (GO) layers through the grafting onto the surface of GO as one of the excellent tools to improve the solubility and the processing ability of graphene. Methylene blue (MB)-mediated intercalation of graphite (flake) was first performed at 25 A degrees C in aqueous media, followed by the Hummers' process for oxidation, leading to an efficient production of GO. Direct oxidation of graphite (powder) also yielded the corresponding GO. The reaction of neutralized GO with "living" PEOs synthesized from alkyllithium- or sodium azide-initiated polymerization of ethylene oxide (EO) in polar solvents led to the production of the corresponding graphene oxide-g-PEOs soluble in different solvents such as tetrahydrofuran (THF), methanol, dimethyl sulfoxide (DMSO), and H2O, etc. The resulting products were characterized by the combination of size exclusion chromatographic, H-1 nuclear magnetic resonance (H-1 NMR), Raman, thermogravimetric anlysis (TGA), transmission electron microscopy (TEM), and atomic force microscopy (AFM) analyses.