Stretchy wearable sensors can tell when you're about to get sunburnt

Image: RMIT

A device the size of a nicotine patch could soon tell when you've spent too long exposed to the sun and need to take a break.

Researchers at the Royal Melbourne Institute of Technology (RMIT) in Australia have created wearable stretchable sensors that could be worn on the skin, capable of detecting ultraviolet (UV) radiation and dangerous gases.

The team have shown they can take an ordinary material such as zinc oxide — a key ingredient in sunscreen — and turn it into an unbreakable electric sensor patch, less than a millimetre or so thick, Ph.D researcher Philipp Gutruf told Mashable Australia.

To make the sensor stretchy and mobile, the scientists transferred the zinc oxide onto a silicone rubber substrate, a material often used in contact lenses.

Close up, the zinc oxide layers look much like the tectonic plates of the earth's crust on a tiny scale, Gutruf said, so they can slide around and allow the sensor to flex. "They move over each other very easily, so we don't need to encase it in a hard material."

"Most of the stretchable electronics that you see, they're basically something hard encapsulated in a rubbery form," Gutruf said. RMIT's sensor, on the other hand, is completely flexible and transparent, so it could easily be added to clothes, wrist bands or any wearables.

Published in the nano-science journal Small, the research has various uses. Because the sensor can detect UV radiation, it's suitable as a wearable outdoor item, especially in Australia with its high UV levels. "You could even make it into a wristband you could wear to the beach," Gutruf said. "Your smartphone could alert you when you'd spent too long exposed and help prevent serious sunburn."

The sensor can also sense some of the contributors to smog, including nitrogen dioxide, so people could monitor how much smog they have been exposed to.

The other benefit of RMIT's work is that these devices are potentially very cheap. The materials, especially the silicone, is really low cost, he said. And zinc oxide is already manufactured in large quantities for sunscreen.

There's still some work to be done. Gutruf and his team are working on adding more functionality to the sensor, with the aim of making devices that seamlessly integrate with the human body.

"Hard, rigid devices are no good," Gutruf said. "It would be a lot more elegant if you could wear your smartphone, for example. This is where the future is going."