INFLUENCE OF FLAKE SIZE ON THE MORPHOLOGY OF WET SPUN GRAPHENE OXIDE FIBERS

For using graphene in practical applications, it is crucial to transform the unique and individual properties of graphene flakes into ordered macroscopic materials. The physical and chemical properties of macroscale graphene structures are closely related to the size of graphene flakes as building blocks. However, the chemical methods adopted to synthesize graphene oxide (GO) flakes offer no tight control on the dimensionality of the ensuring flakes sizes. The goal of this study is to investigate morphological evaluation of graphene based fibers fabricated using building blocks with different average size.. A facile and effective centrifugation method was carried out for size sorting of graphene oxide flakes. Macroscopic graphene oxide fibers were continuously spun from graphene oxide/water suspensions followed by chemical and thermal reductions to obtain reduced graphene oxide fibers. All wet spinning parameters such as suspension concentration, injection rate and nozzle diameter were fixed to investigate the effect of average building block size on the structural morphology of the fibers. Microscopic investigations revealed that the flake size have an enormous impact on the morphology of graphene oxide fibers. The increased average flake size results in the fibers with rectangular-like cross-section and increased amount of voids within the graphene oxide fiber.