An international team of researchers just announced a simple, inexpensive way to spray graphene onto substrates at supersonic speeds. Besides sounding absolutely awesome, the method also offers a solution to a crippling weakness with the supermaterial. In effect, spray-on graphene is simply stronger.
Despite being one of our most exciting supermaterials, graphene's weaknesses are well-documented. Basically, while it's virtually indestructible in microscopic portions, defects appear as you scale up. "Normally, graphene is produced in small flakes, and even these small flakes have defects," explains Alexander Yarin, lead investigator on a study about the new method. But if you imagine how specks of liquid flow out of a can of spray paint and then consolidate on the wall, you can understand how a similar approach works with graphene.
With graphene in the equation, though, you need something a lot more powerful than aerosol. So the researchers repurposed a unique kinetic spray deposition system and a Laval nozzle—the same sort of thing used in supersonic jet engines—to produce a torrent of graphene droplets. The energy of the impact forces the carbon atoms to rearrange themselves into that perfect graphene grid you're always hearing about, except without the defects. "We're tapping into graphene's plasticity," says Yarin, "It's actually restructuring."