Readily Dispersible Chemically Functionalized Reduced Graphene Oxide Nanosheets for Solution-Processable Electrodes and Conductive Coatings

Abstract

Reduced graphene oxides (rGO) are a promising class of materials for scalable electrodes and performance enhancing additives; however, commercial deployment of these materials is challenged by their poor solubility and tendency to aggregate. This research demonstrates the grafting of alkyl functional groups onto rGO nanoparticles—an approach that enhances their processability and requires only simple purification processes. Extended reaction times are shown to increase the extent of functionalization as measured by XPS and thermogravimetric analysis. The chemically functionalized rGOs exhibit an enhanced dispersion in numerous solvents, some of which are low boiling point and provide opportunities for solution processing. The alkyl functional groups confer a slight reduction in electrical conductivity from 750 to ≈400 S/cm. This conductivity is sufficient for applications including static charge dissipation, ohmic heating, and electron capacitance tomography. As a demonstration, electrically conductive thin films of the chemically modified rGO nanoparticles are fabricated via solution casting from chloroform. These films exhibit low sheet resistances of 30 Ω/sq and appear tolerant to simulated space radiation generated at the NASA Space Radiation Laboratory.