Anybody who tries to keep up with nanotechnology is familiar with the many news stories about the potential applications of graphene. These stories remind me of the stories about the potential applications of nanotubes that proliferated just a few years ago.
Graphene is actually very similar to carbon nanotubes: both are composed of carbon atoms linked together. The difference is that graphene is a flat layer of carbon, only one atom thick, where nanotubes are carbon atoms rolled up into a tube shape. The great strength that nanotubes are known for is a result of the bonds between carbon atoms. Those same bonds ensure that graphene is also a very strong material. However, when used in composites, one key difference between graphene and nanotubes is exposed.
When nanomaterials are used in composites they provide strength and stiffness to lightweight items such as tennis racquets and windmill blades. Researchers at Rensselaer Polytechnic Institute have conducted studies comparing the strength of a composite material prepared with an epoxy containing graphene to material prepared with an epoxy containing carbon nanotubes. They report that it takes much less graphene than nanotubes (one tenth the weight) to achieve the same material strength. Apparently this is because the graphene makes a stronger connection with the polymer molecules in the composite due to the surface area of the sheet which is larger than the surface area of a nanotube. Also, the method used by researchers at Rensselaer to manufacture the graphene produced a wrinkled surface which helped the graphene connect with the polymer.
It will be interesting to see if graphene takes over from nanotubes and carbon fibers in the manufacture of strong, lightweight composites. While results from recent studies are promising, the speed at which graphene is adopted will depend upon development of a low cost/high volume method for manufacturing graphene. Researchers at Rice University reported a promising method recently, but it may take a few years to see if all these studies result in practical, widely used materials.
There are several other applications of graphene under development. For more information on these developments go to UnderstandingNano's Graphene Applications webpage at http://www.understandingnano.com/graphene-applications.html