A dash of graphene can transform the stretchy goo known as Silly Putty into a pressure sensor able to monitor a human pulse or even track the dainty steps of a small spider1.
The material, dubbed G-putty, could be developed into a device that continuously monitors blood pressure, its inventors hope. It also demonstrates a form of self-repair that may herald smarter graphene composites.
Since graphene was first isolated in 2004, researchers have added these atom-thin sheets of carbon to a panoply of different materials, hoping to create composites that benefit from its superlative strength and electrical conductivity. But there have been surprisingly few attempts to blend it with ‘viscoelastic’ materials such as Silly Putty, which behaves as both an elastic solid and a liquid. Leave a lump on top of a hole, for example, and it will slowly ooze through.
Conor Boland, a researcher working in Jonathan Coleman’s nanotechnology lab at Trinity College Dublin, wondered what would happen if he brought the two materials together. “I’d like to be able to say it was carefully planned, but it wasn’t,” laughs Coleman. “We’ve just got a tradition in my group of using household stuff in our science.” (In 2014, his team found that they could make graphene by blitzing graphite in a kitchen blender2).