As any dermatologist will tell you, it’s important to know when to get out of the sunlight – or at least, when to apply more sunscreen. As a result, there are now various UV exposure-monitoring devices that tell us when to seek the shade. Not everyone wants to buy one, however, plus some of the single-use models contain environmentally-harmful materials. With that in mind, scientists have developed cheap, disposable eco-friendly sensors that are made of paper.
Using an inkjet printer, non-toxic titanium dioxide and a food dye are both applied to a paper substrate. When exposed to UV light for long enough, the titanium dioxide acts as a photocatalyst, degrading the dye and causing it to change color. That color-change, which can easily be detected by the unaided eye, lets users know that they’re in danger of getting sunburned.
via Gizmag
Image: Kelly Sue DeConnick/CC 2.0
