Synthesis, Characterization And Template-Application Of Graphene Oxide-Based Two Dimensional Macromolecular Brushes

Graphene, single-atom layer of graphite, is a new carbon material following fullerene and carbon nanotubes. Because of its unique mechanical, thermal, and electrical properties, graphene promises great potential applications in many fields such as field-effect transistors, integrated circuits, quantum devices, energy storage materials, functional composite materials, and so on. However, graphene is insoluble in solvent, hard to be processed, and easy to agglomerate in bulk, which hampers its applications. To resolve such problems, graphene should be functionalized.Herein, a general strategy for functionalization of graphene oxide (GO) sheets and facile synthesis of GO-based 2D macro molecular brushes is presented and demonstrated. The ultraflat one-atomic layer of graphene oxide with micrometer-scale sheet topology was employed as the macro molecular backbone; more than 10 types of polymer chains were covalently tethered to the mainsheets 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 1.59×104 arms perμm2 of single side of graphene show high solubility (～15mg/mL), low intrinsic viscosity (～100mL/g), 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.Furthermore, this strategy has been extended to prepare poly(3-(Trimethoxysilyl)propyl methacrylate)-grafted GO sheets (PTPMA-g-GO) Then PTPMA-g-GO was treated with corsslinking in ammonia and freeze-drying followed by calcination at 700℃for 10 hours in air to prepare ultrathin 2D silica sheets (-5nm). The characterizations of AFM, TGA, SEM, TEM and Raman spectroscopy confirmed the structure and morphology of the as-prepared silica sheets. Such an exploration not only provides a facile and efficient method to obtain 2D nanomaterials but also opens up a new way for the application of GO-based 2D molecular brushes.