There are already machines out there equipped with good pressure sensors, but those sensors are rarely sensitive or durable enough to make the machines as useful as humans at performing fine motor tasks. A new kind of graphene “skin” could change that, making it possible to create touch-sensitive robotic hands or even whole robotic medical assistants.
Using this graphene skin, scientists at Monash University’s Center for Atomically Thin Materials in Australia have been making stretchable pressure sensors can snap back into shape after being deformed. They can also can sense every minute of the deformation. They describe their results in a new paper in the journal Advanced Materials.
Graphene is the thinnest material known to science, a layer of carbon atoms just one atom thick, arranged in a honeycomb pattern. Researchers hope it can someday be used in a broad range of applications, from purifying drinking water to charging cell phones more quickly.
The newly developed graphene skin makes use of the material piezoresistive properties. You can run a current through piezoresistive materials and they’ll hold up just fine. Deform them, and their resistance to the current goes up. Let them move back into place and their resistance goes back to normal. By measuring the resistance through a piece of material, you can measure how much it has deformed, and thus determine how much pressure has been applied.
However, piezoresistive materials are not sensitive enough to vibration, in part because they don’t readily pull back to their original shape after being deformed. In contrast, the graphene skin springs back easily, and can sense a wide variety of frequencies. So depending on advances in robotics—namely soft robotics—the world could one day see a big huggable machine like Baymax from Big Hero 6. All thanks to graphene.
[Ultrafast Dynamic Piezoresistive Response of Graphene-Based Cellular Elastomers via Phys.Org]
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