At the moment, GOgraphene sells graphene oxide as both aqueous dispersions and freeze dried powders. The powders were added to the product range to allow researchers to use GOgraphene's graphene oxide in non-aqueous systems (watch a video of our Graphene Oxide dispersions dispersing in water). “Non-aqueous” clearly covers a large number of media and the GOgraphene team wanted to learn more about which solvents their graphene oxide powder would disperse in.
From experience the GOgraphene team know how easily their graphene oxide powder disperses in water and based on available literature they knew that graphene oxide should disperse well in many polar solvents. To find out if GOgraphene's graphene oxide powder disperses as well in other polar solvents as it does in water, the team decided to put it to the test.
Using water, dimethylformamide (DMF), isopropyl alcohol (IPA) and ethylene glycol, 0.5 mg/mL graphene oxide dispersions were prepared using GOgraphene's freeze dried graphene oxide powder. The dispersions were left in an ultrasonic bath for 3 hours at ambient temperature and the results are shown in the picture above. The freeze dried powder dispersed well in all 4 solvents - another success for the GOgraphene team!
Watch the video to see how easily GOgraphene concentrated graphene oxide dispersion can be diluted.
The GOgraphene chemists have worked hard to develop a concentrated graphene oxide dispersion which can be diluted simply and easily. This has been an important part of our product development so far, with an R&D programme focussed on how our customers work with graphene oxide. By offering a highly concentrated dispersion (10 mg/mL) researchers using GOgraphene’s graphene oxide can buy a standard concentration and have the opportunity to work with more concentrations depending on what their research requires.
There are reports of higher graphene oxide dispersions leading to agglomeration of the graphene oxide sheets which then require extensive sonication to separate back out again. To overcome this, William Blythe focussed research efforts on developing a concentrated dispersion which will not suffer this problem. The result is the 1% aqueous dispersion currently offered in the GOgraphene range. Water can be added to this dispersion to dilute to the required concentration, with no large agglomerates present to the human eye. And you don’t need to take our word for it, the video below illustrates beautifully how well GOgraphene’s concentrated dispersions can be diluted.
It should be noted that the general consensus is to use some form of sonication on all graphene oxide dispersions before use. The benefit of GOgraphene’s 1% aqueous dispersion is two-fold; sonication is not needed to form a more dilute dispersion which is comparable to the same concentration at point of sale and secondly that any sonication applied can be provided via an ultrasonic bath, there is no need for a sonic tip.