Lateral size selection of surfactant-stabilised graphene flakes using size exclusion chromatography

Aqueous dispersions of graphene, stabilised by a surfactant, have been separated according to lateral flake size using size exclusion chromatography. Transition electron microscopy was used to characterise the flake size as a function of fraction number. While the stock dispersion had a mean lateral flake size of 0.6 mu m, the separated fractions displayed clear size separation, with the second and fourteenth fractions displaying mean sizes of similar to 1.2 and similar to 0.5 mu m, respectively. Raman spectroscopy shows the flake D:G intensity ratio to scale inversely with the flake size indicating that any defects present are associated with flake edges rather than basal plane defects. (C) 2012 Elsevier B.V. All rights reserved.