More transparent than glass, new material cools rooms and self-cleans

Image: Gan Huang, KIT

Image: Gan Huang, KIT

Having lots of glass surfaces can brighten up a room, but it also lets in too much heat as well as neighbors’ prying eyes. A new metamaterial is not only more transparent to light, but adds privacy, cools the room inside, and automatically cleans itself.

Known as a Polymer-based Micro-photonic Multi-functional Metamaterial (PMMM), the new creation takes the form of a thin film that can be stuck onto a pane of regular glass. It gets its special properties from the microscopic structure of its surface, which is etched with a pattern of pyramids each just 10 microns wide.

These mini-pyramids scatter 73% of the light that hits them, which gives the material that frosted look. But despite that, it’s surprisingly more transparent to light than regular glass – 95% transmittance compared to the usual 91% of most glass. That makes for a more comfortable lighting not just for people, but plants as well.

PMMM’s coolest trick (pun intended) is its ability to beam heat directly into outer space, thus cooling a room. It sounds like sci-fi stuff, but it’s a well-studied phenomenon called radiative cooling that takes advantage of the fact that the Earth’s atmosphere is transparent to infrared wavelengths.

The film is also self-cleaning. The surface full of tiny pyramids keeps a layer of air underneath any water droplets, so they just roll right off, taking any dust or dirt with them. Technically, this makes it superhydrophobic, with a contact angle of 152 degrees.

Source: New Atlas

Image: Gan Huang, KIT