Synthesis and Characterization of Defective Graphene Based Nanocomposites

Abstract

As a new emerging nanomaterial for thin film electronics, two-dimensional (2D) graphene sheets derived from bulk graphite have been considered as the thinnest functional nanomaterial because of an atomic scale thickness and infinite planar dimensions with unique physicochemical properties. Graphene oxide (GO) nanosheets are one of those materials, made by the strong oxidative exfoliation of pristine graphite. GO nanosheet is an oxidized form of graphene, which are described as a random distribution of oxidized areas bearing the oxygenated functional groups such as carboxylic acids, epoxide, and hydroxyl groups,combined with non-oxidized regions wherein most of the carbon atoms preserve sp2 hybridization. In addition, it brings many topological defects in graphene domains due to the strong oxidation process; these characteristics are different from the conventional graphene structure. In that regards, GO nanosheets are sometimes represented by a “defective graphene”,which inevitably degraded its intrinsic electronic and mechanical properties. However, the presence of oxygen functionalities not only affords hydrophilic, negatively charged graphene oxide sheets with high dispersion capability, but also act as excellent substrates for hosting and growing functional nanomaterials, including other carbon allotropes, inorganic nanostructures, polyelectrolytes, and biomolecules. Thus, GO can easily be mixed with different polymers and other materials, and enhances properties of composite materials like tensile strength, elasticity, conductivity and more. Furthermore, the hybridization of the carbon nanomaterials with the exceptional versatility of the nanoscale construction of multilayer films using layer-by-layer (LbL) assembly has opened up wide research opportunities. In addition, various functionalities can be achieved by the carbon nanomaterials through a facile chemical modification, which makes it easy to host and grow the functional nanomaterials on the surface of carbon nanomaterials. Thus, this approach offers virtually unlimited opportunities for expanding the material selection for LbL deposition.