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

Abstract

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 m, the separated fractions displayed clear size separation, with the second and fourteenth fractions displaying mean sizes of ~1.2 and ~0.5 microns 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.

A comparison of catabolic pathways induced in primary macrophages by pristine single walled carbon nanotubes and pristine graphene

“…Previously, it has been shown that an increase in the relative intensity of the D band with respect to the starting material for liquid phase exfoliated samples is consistent with the creation of edges, as flakes are cut during sonication. [10][11][12] It is also important to note that the change in the 2D band for graphene films compared to the bulk graphite is indicative of exfoliation. 13 Xray photoelectron Carbon 1s core level spectra were measured on relatively thick vacuum deposited PG and pSWCNT films, as shown in Figure 1 (C&D) Both the flakes and the nanotubes show a dominant sp 2 carbon component, as is expected for high quality samples, and show similar relative amounts of the different oxide species (C-O, C=O and COOH), as shown in Table 1, at higher binding energy values indicating that the two samples are chemically very similar.…”

Exfoliation of Few‐Layer Graphene in Volatile Solvents Using Aromatic Perylene Diimide Derivatives as Surfactants

“…This approach has been generalized successfully to produce other 2 D materials such as boron nitride (BN) and transition metal dichalcogenides (TMDs) . Purification of the monolayers is achieved by centrifugation steps or by chromatography for applications such as transparent conductors, for which monolayers are required.…”

Lateral size selection of liquid exfoliated hexagonal boron nitride nanosheets

“…Therefore, it is considered to be quite effective in studying the graphene in which there are generally D, G, and 2D characteristic bands around 1350, 1580 and 2700 cm À1 and the longitude and lateral sizes can be unambiguously determined by the Raman intensity ratio between G and D (2D) bands. 33,34 However, BN nanosheets do not exhibit a Raman D band due to the lack of Kohn anomaly, leaving difficulties in extracting the size information through similar procedure. Fig.…”

“…20,31 Moreover, a great deal of efforts on Raman spectra of D and G bands of carbon has been proposed to measure the lateral size and thickness of graphene and graphene oxide akes indirectly. [32][33][34] In spite of the similar structure to graphene, recently Raman signature and phonon dispersion of h-BN nanosheets (BNNSs) have been found not thickness-related, 35 though it is widely used to characterize the properties of BNNSs. 36 Thus, it is highly indispensible to search alternative methods to sort the lateral size and thickness of h-BN nanomaterials.…”