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ACS News Service Weekly PressPac: Wed Dec 02 08:42:00 EST 2015

New stretchable, wearable sensor made with chewing gum (video)

Gum Sensor: A Stretchable, Wearable, and Foldable Sensor Based on Carbon Nanotube/Chewing Gum Membrane
ACS Applied Materials & Interfaces

Body sensors, which were once restricted to doctors’ offices, have come a long way. They now allow any wearer to easily track heart rate, steps and sleep cycles around the clock. Soon, they could become even more versatile — with the help of chewing gum. Scientists report in the journal ACS Applied Materials & Interfaces a unique sensing device made of gum and carbon nanotubes that can move with your most bendable parts and track your breathing.

Most conventional sensors today are very sensitive and detect the slightest movement, but many are made out of metal. That means when they’re twisted or pulled too much, they stop working. But for sensors to monitor the full range of a body’s bending and stretching, they need a lot more give. To meet that need, some researchers have tried developing sensors using stretchy plastics and silicones. But what they gained in flexibility, they lost in sensitivity. Malcolm Xing and colleagues found a better solution right under their noses — and in their mouths.

To make their supple sensor, a team member chewed a typical piece of gum for 30 minutes, washed it with ethanol and let it sit overnight. The researchers then added a solution of carbon nanotubes, the sensing material. Simple pulling and folding coaxed the tubes to align properly. Human finger-bending and head-turning tests showed the material could keep working with high sensitivity even when strained 530 percent. The sensor also could detect humidity changes, a feature that could be used to track breathing, which releases water vapor with every exhale. 

See the sensor at work in this ACS Headline Science video.

Scientists make a sticky, stretchy sensor out of chewing gum and nanotubes.
Credit: American Chemical Society
ACS Headline Science video