Rodney Ruoff and colleagues at Northwestern University say the resulting graphene creates a new electrically conducting composite material.

Graphene has recently become a most-studied material, since it might provide the fabric for new kinds of microelectronic devices and circuits, but it has been hard to create.

Graphite is a form of pure carbon made from stacks of flat sheets but making it difficult since the sheets tend to stick together.

The researchers found a way to turn graphite oxide into a graphene polymer composite by modifying it with a chemical so that, upon exposure to ultrasound, it will exfoliate in solvents that also dissolve polymers.

That approach is the basis for the generation of polymer matrix composites containing graphene sheets. A reducing step introduced before polymer-graphene coagulation led to the formation of an electrically conducting material.

The research is described in the journal Nature.