A silly putty sensor is a sensing device made of G-putty, a polysilicone polymer infused with graphene. Graphene is a highly-conductive carbon allotrope whose atoms are arranged in a mesh-like structure just one atom thick.
The addition of graphene to the stretchy, moldable substance sold as Silly Putty® makes the substance not only conductive but also able to detect even tiny changes in pressure, impact and strain. The electrical resistance of the material increases dramatically when the substance is deformed in any way -- by stretching, for example, or pressure. The mesh-like structure in sheets of graphene in the putty forms and breaks networks as the material changes shape.
The new substance could have many applications in sensor manufacturing and be especially useful in wearable medical and health devices. A small silly putty sensor placed over the carotid artery, for example, could be used to continuously monitor pulse rate and blood pressure. One placed on the chest could be used to monitor breathing for conditions like sleep apnea. G-putty pressure sensors could be used wherever more conventional devices are employed, including factory robots and autonomous driving systems.
Researchers from Trinity College Dublin and the University of Manchester discovered the properties of G-putty in a collaborative project. Although graphene had been added to polymers before, the capacities created by combining it with a stretchable and moldable substance surprised the researchers.
Watch a brief introduction to the silly putty sensor: