Graphene for your loudspeakers
12 July 2011 - Nanotech
Graphene for your loudspeakers is just one potential graphene application under investigation and Keun-Young Shin and colleagues of the oddly sounding World Class University have devised a way to make it possible (DOI). Graphene is a great electron conductor. It is also potentially cheap to use in electronics if only you find a way to deposit the material in the right positions with the right thickness. The Keun-Young Shin solution: an inkjet printer and the concept is demonstrated in a loudspeaker application.
Here is the recipe: take a 100 mm by 100 mm piece of transparent (60 micron) polyvinylidene fluoride (piezoelectric!) and modify its surface energy by an oxygen plasma flow to match that of the ink to be employed. Then take a solution of exfoliated graphene oxide flakes in water and and use a commercial inkjet printer to print a specific pattern onto the PVDF film at two sides. Repeat printing multiple times to get complete coverage. The reduce the GO to graphene at 90°C with hydrazine and ammonia. The two graphene layers are also transparent making the whole loudspeaker sheet transparent as well.
The real interest in this venture is of course not the loudspeaker but the quality of the graphene film. The TEM image speaks for itself: complete coverage with patches of bilayers and trilayers.