Although you might not think that a plain old heating pad could be dangerous, the things do burn people on a regular basis. It can be particularly common with the elderly, whose compromised sensitivity doesn't always let them know when there's too much heat. Of course, they could always just look to see if their skin is getting red, although they'd have to remove the pad to do so. That's why scientists have created a clear heating pad.

Led by associate professor Wei Lan of China's Lanzhou University of Technology, the researchers made their thermotherapy pad by first embedding conductive silver nanowires in a thin polyvinyl alcohol film. That film – along with a copper electrode – was then encapsulated within a transparent, biocompatible type of silicone known as polydimethylsiloxane.

The resulting highly-flexible device heats up quickly and evenly when just 3 volts are applied, and keeps working even after being bent 10,000 times. By contrast, other groups' previous attempts at transparent heating pads were reportedly "too stiff, costly or brittle."

Lan and colleagues have suggested that the technology might also find use in windows, vehicle headlights or camera lenses that auto-defog and melt ice – although Volkswagen has already created a silver nanowire-equipped ice-melting windshield.

A paper on the Lanzhou research was recently published in the journal ACS Applied Materials & Interfaces.