Graphene is essentially a two-dimensional sheet of carbon atoms, arranged in a hexagonal pattern. This deceptively simple material has a range of useful properties – it's incredibly lightweight, thin and flexible, but still strong. It's also an excellent conductor of electricity and heat, so it's turning up in everything from electronics to water filters to clothing.
Ideally, one useful way to get graphene into the right configurations could involve dispersing it in water. This solution could then be painted or sprayed onto a surface to make, for example, supercapacitor electrodes or conductive coatings.
The problem is that graphene and similar forms of carbon, like graphite and carbon nanotubes, are hydrophobic, meaning they repel water. They can be made to disperse using harsh organic solvents or mechanical treatments, but the former is toxic and the latter can introduce defects.