I bought some graphene powder (1-3 layer) that was made by CVD. But I need to make a suspension of graphene in water to use it in an electrolyte solution. Can someone explain to me what the simplest way?
Some papers report that surfactant has positive effect on dispersion of CNT in water also has preventive effect on agglomeration ,So I guess it perhaps has same effect on graphene dispersion too !
There are a lot of cheaper options to make graphene powder, which is redispersible in water, such as reduced graphene oxide, sonicating graphite/surfactant and ball milling of graphite.
tnx for your kind recommendation. Actually I bought these graphene in shape of large flakes ,But I need to a suspension of fine graphene sheets in water, So milled them to reach graphene powder, But now i guess their structure may be deformed by
milling !!! I'm really confused, Perhaps I wasted a lot of money :-(
Actually what is the best , simplest and Cheapest option ?
With graphene oxide, in water, you can make your material (composite, ...) then expose them to a reducing agent. Also there are ways to have reduced graphene oxide in water. (Nature nanotechnology 3 (2), 101-105)
If you want to use graphene oxide, I would suggest to synthesis that by yourself its very easy.
If you seek for other options, just add graphite powder (1 mg/ml) to a surfactant solution (such as SDS 5mg/ml) or organic solvents (NMP, DMF).
Bath sonicate the mixture for at least a day. Then let them rest for an overnight followed by 1h centrifugation for at least 5000g. The top of the dispersion will contain graphene (1-5%) and few layers graphene.
Surfactants are the best way to obtain a better graphene -Water dispersion. try with SDS , if you are working with concentration below 1mg/ml . then you can use low SDS concentration (the best dispersion is obtained at a concentration of 2.8 mM which is the Sac concentration ( the surface aggregation concentration ). if you are working with very higher graphene concentration you should use SDS concentration above the CMC (Critical micelle concentration).
This publication may help you :
High-yield graphene exfoliation using sodium dodecyl sulfate accompanied by alcohols as surface-tension-reducing agents in aqueous solution.
Bath type sonicators offer mild mixing due to their indirect transfer of energy. Probe type sonicators offer aggressive shearing which may alter the physical properties of FLGs.
I suggest you try bath type first, see if that works for you. If not, probe type it is.
Thank you. I have tried ultrasonicator for GO dispersion at 30% amplitude now im afraid if Ive damaged it before reduction; after which i did bath sonication. Should i expect my RGO particles to be completely homogenized because i dont know if its sufficient already when i still see separate particles at 25mins.