World's most sensitive strain sensor can detect the weight of a feather

Researchers created a new strain sensor material by incorporating graphene into a unique polymer matrix. Photo by University of Sussex
Researchers created a new strain sensor material by incorporating graphene into a unique polymer matrix. Photo by University of Sussex

June 4 (UPI) -- Scientists have unveiled the world's most sensitive strain sensor, capable of detecting the weight of a single feather.

The sensor is significantly more stretchable, capable of enduring 80 times greater strain than current commercial sensors, and is able to register resistance changes with 100 times the precision of current sensors, researchers said.


The new strain sensor -- described Thursday in the journal Advanced Functional Materials -- could be used to improve the sensitivity of a variety of medical and wearable devices.

"The next wave of strain sensing technology uses elastic materials like rubber imbued with conductive materials such as graphene or silver nanoparticles, and has been in development for over a decade now," lead study author Marcus O'Mara, researcher at the University of Sussex, said in a news release.

"We believe these sensors are a big step forward," O'Mara said. "When compared to both linear and non-linear strain sensors referenced in the scientific literature, our sensors exhibit the largest absolute change in resistance ever reported."

According to Alan Dalton, study co-author and professor of experimental physics at Sussex, the device could be used to measure joint movements of an athlete or the vital signs of a hospital patient.


"Multiple devices could be used across the body of a patient, connected wirelessly and communicating together to provide a live, mobile health diagnostics at a fraction of the current cost," Dalton said.

Researchers created the new strain sensor by carefully incorporating large amounts of graphene nanosheets into a matrix composed of the composite material polydimethylsiloxane, or PDMS.

According to the new study, PDMS is "biocompatible, elastic, transparent, durable, and has very minimal shrinkage on curing."

PDMS is normally resistant to mixing, but researchers developed a novel process for incorporating graphene into the composite material -- methods that researchers suggest could be used to develop other kinds of two-dimensional layered materials and polymer matrices.

Most strain sensors are limited in either their range or their sensitivity, but the latest strain sensor material is able to take on large amounts of strain while also registering tiny changes in strain.

"Nanocomposites are attractive candidates for next generation strain sensors due to their elasticity, but widespread adoption by industry has been hampered by non-linear effects such as hysteresis and creep due to the liquid like nature of polymers at the nanoscale which makes accurate, repeatable strain readouts an ongoing challenge," said Sean Ogilvie, researcher fellow at Sussex.


"Our sensors settle into a repeated, predictable pattern which means that we can still extract an accurate read-out of strain despite these effects," Ogilvie said.

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