Graphene and Graphene Oxide and Their Uses in Barrier Polymers

Currently, there is great interest in graphene-based devices and applications because graphene has unique electronic and material properties, which can lead to enhanced material performance. Graphene may be used in a wide variety of potential applications from next-generation transistors to lightweight and high-strength polymeric composite materials. Graphene, which has atomic thickness and two-dimensional sizes in the tens of micrometer range or larger, has also been considered a promising nanomaterial in gas-or liquid-barrier applications because perfect graphene sheets do not allow diffusion of small gases or liquids through its plane. Recent molecular simulations and experiments have demonstrated that graphene and its derivatives can be used for barrier applications. In general, graphene and its derivatives can be applied via two major routes for barrier polymer applications. One is the transfer or coating of few-layered, ultrathin graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), on polymeric substrates. The other is the incorporation of fully exfoliated GO or rGO nanosheets into the polymeric matrix. In this article, we review the state-of-the-art research on the use of graphene, GO, and rGO for barrier applications, including few-layered graphene or its derivatives in coated polymeric films and polymer nanocomposites consisting of chemically exfoliated GO and rGO nanosheets, and their gas-barrier properties. As compared to other nanomaterials being used for barrier applications, the advantages and current limitations are discussed to highlight challenging issues for future research and the potential applications of graphene/polymer, GO/polymer, and rGO/polymer composites. (C) 2013 Wiley Periodicals, Inc.