Electrical resistance tests revealed G-putty was highly sensitive to the slightest deformation or impact — at least 10 times more sensitive than other nanocomposite sensors

Silly Putty may no longer be silly, at least according to researchers
at Trinity College Dublin. After adding graphene flakes to the novelty toy, the
team discovered it works as a pressure sensor that can monitor blood pressure, among other things. Who
would have thought? Not my nine-year-old self.

Graphene, which consists of carbon atoms linked together to
form a one-atom-thick sheet, could be described as a wonder material. It’s
highly electrically conductive, chemically stable, and is incredibly strong. Silly
Putty is a gooey old-school children’s toy, or so we thought.

Coleman_and_Son_G-putty

Lead scientist Jonathan Coleman and his son Oisin, with G-putty and regular Silly Putty. Image source: AMBER, Trinity College Dublin. 

In collaboration with Professor Robert Young of the
University of Manchester, an AMBER team (meaning an Irish materials research
center hosted by Trinity College Dublin) led by Professor Jonathan Coleman
added a small amount of graphene flakes to some Silly Putty. The resulting
material, dubbed as G-putty, is electrically conductive.

To make the new material, polydimethylsiloxane (PDMS) was
heated with boric acid, which linked the oil’s polymer chains together to form
a putty. Then, graphene flakes were made from graphite using liquid phase
exfoliation, which left graphene suspended in solvent. Lastly, the two
components were mixed and the solvent boiled off to leave a graphene-infused
putty.

Electrical resistance tests revealed that G-putty was highly
sensitive to the slightest deformation or impact — at least 10 times more
sensitive than other nanocomposite sensors. In one study, a sheet of cling film
coated with G-putty detected the individual footsteps of a small spider — weighing
just 20 mg —
scurrying over the surface.

If that’s not
impressive enough, when
the material was placed against the chest or neck of test subjects, it was able
to measure breathing, pulse, and blood pressure. Other experiments showed G-putty
sensing joint motions, such as finger-wagging.

According
to the research team, G-putty is hundreds of times more sensitive than
traditional sensors used in applications such as medical devices. This
unique discovery can open up major possibilities in sensor manufacturing all
over the world.

So, point proven. Play is the highest form of research.

This study was originally published in the journal Science.