During its existence, graphene has established itself as a versatile material with unique properties. However, it also has a drawback - "unwillingness" to disperse, that is, to be crushed to a state of dispersion, which in turn prevents the creation of paints and inks on its basis.
Researchers at Umeå University (Sweden) have found a relatively simple way to solve this problem by using graphene oxide. It is a slightly different kind of carbon that can provide stable dispersion in water and can then be used as a graphene paint.
The difficulty lies in the fact that graphene and similar carbon compounds (graphite, nanotubes) are hydrophobic, that is, they repel water. They can be dispersed using aggressive organic solvents or mechanical treatments, but the first method is toxic, and the second is fraught with the formation of defects.
Scientists have proposed using oxidized graphene, which is hydrophilic. By combining graphene oxide with particles of other hydrophobic carbons - graphene, activated graphene, porous and activated carbon, they managed to obtain stable dispersions. As a result, even after a few days, the material did not settle to the bottom of the container with the aqueous solution.
In the next experiment, the researchers added carbon nanotubes to the mixture and tried to make supercapacitor electrodes out of it, for which they applied particles to metal foil, dried and heated to 200 ° C.
According to one of the authors of the study, Alexander Talyzin, "thanks to this we get a thin film of a conductive material with a sufficiently large surface area, good conductivity and excellent properties for storing energy in supercapacitors."