News — Graphene oxide

The GOgraphene team are pleased to announce the addition of graphene oxide flake to their high quality graphene oxide product range. 

The graphene oxide flake offered is formed by drying thin layers of an aqueous dispersion and results in brown-amber discs with approximate diameters of around 0.3 cm – 0.7 cm. As the graphene oxide flakes are made directly from GOgraphene's 1% aqueous graphene oxide dispersions, the flake meets the same stringent quality requirements of the other GOgraphene products.

By drying the GOgraphene graphene oxide dispersions at ambient temperature it is possible for GOgraphene to offer flake as an alternative solid to the freeze-dried powder. The resulting solid products are different and a customer’s choice to use powder or flake will depend on their research facilities. Graphene oxide flake will require more energy to disperse when compared to the freeze dried powder. To check the dispersibility of their graphene oxide flake, the GOgraphene team added their graphene oxide flake to deionised water at a concentration of 0.5 mg/mL and left it to sonicate in an ultrasonic bath. After one hour of sonication in an ultrasonic bath all of the flake had dispersed. The dispersion was left to stand for 7 days, at the end of which no solids were observed. No work has been carried out by GOgraphene on dispersing their graphene oxide flake in any other medium yet. This will be investigated in future work, with findings communicated via the GOgraphene blog. 

GOgraphene’s graphene oxide flake is now available to purchase online in 1 g and 5 g pack sizes and is available for shipment within 21 days of purchase. If you have any questions please get in touch via our enquiry form.

AFM (atomic force microscopy) analysis has now been completed on GOgraphene graphene oxide. The AFM analysis was carried out to investigate both the lateral sheet dimensions and sheet depth, with the intention of discovering how many layers GOgraphene graphene oxide flakes are.

Diluting a sample of our 10 mg/mL aqueous graphene oxide dispersion down to a 1 ppm dispersion, it has been possible to measure the graphene oxide sheet sizes. The high dilution allows the AFM to measure fully dispersed material, without the individual flakes overlapping and consequently leading to more accurate dimensions for fully dispersed sheets.

The lateral dimensions of the plates varied, with the majority of flakes consistently over 5 microns in at least one lateral dimension. This corresponds very well with the SEM images obtained previously which showed lateral dimensions of over 5 microns. While there is currently no industry standard for understanding what the optimal graphene oxide sheet size is, GOgraphene graphene oxide is manufacturing a consistent quality product.

The AFM analysis is of particular interest for understanding the sheet depth. Single layers of graphene oxide are just over 1 nm tall, with greater depths informing the analyst approximately how many layers are stacked on top of one another. A few sheets stacked on top of one another can indicate that the graphene oxide is not fully dispersed into monolayers or that the graphite was not completely oxidised to enable all single layers to form. The AFM analysis on GOgraphene graphene oxide has shown a sheet depth of around 2 nm, proving that the individual flakes are only two graphene oxide sheets tall.

This is an exciting new piece of data for the GOgraphene range which really proves the 2 dimensional nature of graphene oxide. Data collection on our graphene oxide will continue over the coming months, however if there is analysis on our products which isn’t listed on our site yet and you feel it would benefit your research, please get in touch via our enquiry form and we will look into this.