You might be familiar with Vantablack paint that absorbs up to 99.96 percent of light. Xiulin Ruan, a professor of mechanical engineering at Purdue University, and his students came up with the opposite by creating a white shade reflecting 98.1 percent of solar radiation. The material has a cooling effect and might even help fight global warming. A version for cars is on the horizon.
The white paint emits more infrared heat than it absorbs. The paint features various sizes of barium sulfate particles that scatter different wavelengths of solar radiation. This means it cools a surface below the surrounding temperature.
Gallery: World's Whitest Paint
For example, previous experiments showed this paint cooling a surface by 8 degrees Fahrenheit versus the surroundings under noon sunlight. At night, the ultra-white material can keep things 19 degrees Fahrenheit cooler.
The Guinness World Records even recognized this substance as the "Whitest paint." The "This is Purdue" podcast also interviewed Ruan.
In 2022, the team developed a lighter version of the paint that can work on vehicles. It's not clear when this substance might appear on cars. Commercial applications are a year or more away.
Ruan is also working on barium-sulfate paints in different colors. They wouldn't be as effective as the white version but would still have improved reflectivity of solar radiation than existing solutions.
When something is Vantablack, it has a matte black appearance that flattens details into a nearly two-dimensional look. Conversely, the white paint from Purdue University looks like a conventional color that you'd find on a house or car.
BMW painted a 2020 X6 in Vantablack for the 2019 Frankfurt Motor Show (below). It was a way to camouflage the then-upcoming model. The automaker took things a step further at the actual event by displaying the vehicle in a room with ultraviolet and neon lighting.
Gallery: BMW X6 Vantablack at the 2019 Frankfurt Motor Show
Vantablack maker Surrey Nanosystems only sells the paint to customers who request a sales quote. However, the shade Musou Black is widely available and currently costs around $24.00 for a 100-milliliter bottle.
Photos via Purdue University image/Joseph Peoples, Purdue University photo/John Underwood, and Purdue University photo/Jared Pike
