Well, solubility may depend on the size and degree of oxidation. Small, low-oxidized nanoflakes (particles is sometimes used for that, but flakes is the more accurate term) may be soluble in toluene or another non-polar solvent.

Larger flakes may require some sort of surfactant like SDS in water. Please note, however, that this might be tricky to get rid of.

Dear Smita Borse thanks for posting this very interesting technical question. The term "dissolve" is not suitable here. As with all nanoparticles in general, you cannot make a homogeneous solution, but only a dispersion in a variety of solvents. For example, think about ZnO nanoparticles: You can disperse ZnO nanoparticles in water or organic solvents, which is fine. However, when you dissolve ZnO nanoparticles in HCl, you will get a clear solution, but you don't have nanoparticles any more!

For suitable solvents which can be used for preparing dispersions of graphene oxide, please have a look at the following useful article:

Graphene Oxide Dispersions in Organic Solvents

(please see attached pdf file)

I hope this clarifies the issue. Good luck with your work and best wishes, Frank Edelmann

Article Reduced graphene oxide biosensor platform for the detection ...

It depends on the challange and the starting material. Mentioned citation contains a lot of work but finally leads to nearly perfect coatings which can even be reduced to something similar to graphene.

Smita Borse is interested in obtaining a homogenized solution of graphene oxide. Therefore, Jürgen Weippert is right to draw attention to the dissolution of graphene nanoparticles, and not to the preparation of a dispersion of graphene oxide, as Frank T. Edelmann .

However, when discussing this issue, it should be recognized that the terms dissolution and preparation of a dispersion for the octylbenzene solvent coincide. These terms also coincide for obtaining solutions of lyophilic disperse systems. They can be considered solutions and, at the same time, disperse systems. Polymer molecules are large and comparable in size nanoparticles. In our case, the polymer molecule should be considered a nanoparticle of graphene oxide, and the solvent is octylbenzene, which is used to split graphite when graphene is obtained from it.

Dera All, I think that both my previous answer and that of Yuri Mirgorod are correct in some sense. It is in fact true that graphene oxide (GO) is soluble e.g. in water and certain organic solvents such as DMF, N-methyl-2-pyrrolidone, and ethylene glycol. For some more detailed information about the solubility of GO please have a look at the following interesting study:

New insights into the solubility of graphene oxide in water and alcohols

Article New Insights to Solubility of Graphene Oxide in Water and Alcohols

The good thing about this paper is that it is freely available a spublic full text on RG.

My point was that if you have GO nanoparticles and want them to stay nanoparticles, you can only make a homogeneous dispersion. If you dissolve the nanoparticles in any solvent you will get a solution, but the nanoparticles are gone. Evaporation of the solvent will not give you nanoparticles again!

With best wishes, Frank Edelmann

Dear Smita Borse,

The solvent you can use Dimethylformamide or N-Methyl-2-pyrrolidone (NMP) which is an organic compound consisting of a 5-membered lactam.

Regards,

Before to discuss whatever we must define the terms used in the discussion. Are nanoparticles dissolved or dispersed. Is a dispersion homogeneous or heterogeneous?

Definitions recommended by IUPAC

Homogeneity. The degree to which a property or a constituent is uniformly distributed throughout a quantity of material. A material may be homogeneous with respect to one analyte or property but heterogeneous with respect to another. The degree of heterogeneity (the opposite of homogeneity) is the determining factor of

sampling error

Colloidal dispersion. A system in which particles of colloidal size of any nature (e.g. solid, liquid or gas) are dispersed in a continuous phase of a different composition (or state). The name dispersed phase for the particles should be used only if they have essentially the properties of a bulk phase of the same composition.

Solution. A liquid or solid phase containing more than one substance, when for convenience one (or more) substance, which is called the solvent, is treated differently from the other substances, which are called solutes. When, as is often but not necessarily the case, the sum of the

mole fractions of solutes is small compared with unity, the solution is called a

dilute solution. A superscript attached to the ∞ symbol for a property of a solution denotes the property in the limit of infinite dilution

Dissolution. The mixing of two phases with the formation of one new homogeneous phase (i.e. the solution)

Smita Borse If the size of the GO particle are larger than 100nm it is very difficult to obtain a homogenous dispersed solution. For that you may try DMF or NMP. But it might require to be ultrasonicated for more than an hour at temp >40 deg Celsius.

If they are nanoparticles it can easily be dispersed in chloroform/DMF/NMP/ethanol etc.

Hope this helps you.

If the graphene oxide is well oxidized, it will possess oxygen-containing functional groups which among them is also present the carboxylic functional group. Hence this functional group can be deprotonated in basic or neutral solution and make negatively charged groups that will absorb the cations in the solution. For this reason, the graphene nanosheets will be intercalated with the cations to keep charge neutrality. As a result, when graphene oxide is dispersed in basic solutions, it is more stable and makes homogenous dispersion compared to acidic solutions.