A team of researchers at Trinity College in Dublin, Ireland, have used graphene composites to make silly putty® conduct electricity – creating extremely sensitive sensors. The team has been able to mount the new material, known as “G-putty,” onto the chests and necks of human subjects and used it to measure breathing, pulse and even blood pressure. It showed unprecedented sensitivity as a sensor for strain and pressure, being hundreds of times more sensitive than normal sensors.
The G-putty also works as a very sensitive impact sensor, able to detect the footsteps of small spiders. The scientists believe that this material could be used for a wide a range of medical devices, including heart monitors.
“[Silly putty] is different from familiar materials in that it flows like a viscous liquid when deformed slowly but bounces like an elastic solid when thrown against a surface,” explain Coleman. “When we added the graphene to the silly putty, it caused it to conduct electricity, but in a very unusual way.”
As Jonathan Coleman, Trinity’s Professor of Chemical Physics, explains, the team found “unexpected behavior” when it added graphene to silly putty. The team found that the electrical resistance of the G-putty was very sensitive to deformation, with the resistance increasing drastically by even the slightest impact. Coleman said the resistance slowly returned close to its original value as the putty self-healed over time, which is unusual.
“While a common application has been to add graphene to plastics in order to improve the electrical, mechanical, thermal or barrier properties, the resultant composites have generally performed as expected without any great surprises,” said Coleman. “The behavior we found with G-putty has not been found in any other composite material. This unique discovery will open up major possibilities in sensor manufacturing worldwide.”
The team’s complete findings are available in a leading journal, Science. For more information, watch the video below: