The vivid blue color of morpho butterflies doesn’t come from pigment but from tiny nanostructures on their wings that bend and reflect light. In a recent study, scientists designed a thin film with a layer that mimics the wings to create the same color—and doubles as a way to help keep surfaces cool in extreme heat.
In the study, researchers at China’s Shenzhen University tested the film on a car parked in the sun. Another patch of regular blue paint on the car heated up to 167 degrees Fahrenheit. But since the sample painted with the new coating reflected light away, it only reached 107 degrees. Because the car would stay more comfortable inside, it could use less air-conditioning. In an electric car, that would mean saving energy so the car could drive longer distances.
The film was made from a top layer of titanium, silicon, and oxygen; a middle layer of frosted glass designed with the nanostructure of a butterfly wing; and a bottom layer of silver. (All three together measure only a few micrometers thick.) The film can be made into different colors by slightly changing the design; the researchers also tested shades of red and green.
White coatings are already common on buildings to help reduce the need for air-conditioning—and the newest “whitest white” coatings will be able to reflect even more heat. Butterfly-inspired paint could eventually offer a similar function, but in color. The same structural color could also be used on clothing or other products to keep the wearer cool. And if you want a wilder-looking option, other researchers are studying iridescent coatings that could make your future house look like a seashell and help you avoid air-conditioning altogether.