Progress in Imidazolium Ionic Liquids Assisted Fabrication of Carbon Nanotube and Graphene Polymer Composites

Carbon nanotubes (CNTs) and graphene sheets are the most promising fillers for polymer nanocomposites due to their superior mechanical, electrical, thermal optical and gas barrier properties, as well as high flame-retardant efficiency. The critical challenge, however, is how to uniformly disperse them into the polymer matrix to achieve a strong interface for good load transfer between the two. This problem is not new but more acute in CNTs and graphene, both because they are intrinsically insoluble and tend to aggregate into bundles and because their surfaces are atomically smooth. Over the past decade, imidazolium ionic liquids (Imi-ILs) have played a multifunctional role (e.g., as solvents, dispersants, stabilizers, compatibilizers, modifiers and additives) in the fabrication of polymer composites containing CNTs or graphene. In this review, we first summarize the liquid-phase exfoliation, stabilization, dispersion of CNTs and graphene in Imi-ILs, as well as the chemical and/or thermal reduction of graphene oxide to graphene with the aid of Imi-ILs. We then present a full survey of the literature on the Imi-ILs assisted fabrication of CNTs and graphene-based nanocomposites with a variety of polymers, including fluoropolymers, hydrocarbon polymers, polyacrylates, cellulose and polymeric ionic liquids. Finally, we give a future outlook in hopes of facilitating progress in this emerging area. OPEN ACCESS Polymers 2013, 5 848