General Avenue to Individually Dispersed Graphene Oxide-Based Two-Dimensional Molecular Brushes by Free Radical Polymerization

Abstract

We present a general strategy for facile synthesis of 2D macromolecular brushes. The ultraflat one-atomic layer of graphene oxide with micrometer-scale sheet topology was employed as the macromolecular backbone; more than 10 types of polymer chains were covalently tethered to the nanosheets through free radical polymerization, producing various 2D molecular brushes with multifunctional arms covering from polar to apolar, water-soluble to oil-soluble, acidic to basic, and functional to common polymers. The resulting molecular brushes are well soluble in desired solvents in the forms of individually dispersed hairy nanosheets. The growing process of 2D molecular brushes was clearly visualized by AFM. The giant 2D brushes with arm density up to 1.59 × 10 4 arms per μm 2 of single side of graphene show high solubility (∼15 mg/mL), low intrinsic viscosity (∼100 mL/g), and fine electrical conductivity (∼8.4 × 10 −3 S/cm), and they can possess numerous epoxy and other functional groups at their arms if necessary, promising a luciferous foreground in both scientific research and industrial applications. The polymer-grafted graphene oxide can be well dispersed in free polymer matrix and can be well soluble in solvents again, suggesting that nanocomposite of polymer-grafted graphene oxide and polymer can be readily produced by the solution-processing technique.