The ‘Whitest White Paint’ Ever, Opposite Of Anish Kapoor’s Vantablack, Is Here
Image via Purdue University / Jared Pike
Engineers from Purdue University have created the whitest white paint ever, and it is really… bright. Reflecting 98.1% of sunlight, it’s essentially the opposite of ultra-dark paints like Vantablack and MIT’s ‘Blackest Black’.
While creating the brightest paint color ever is a feat in itself, the team behind the creation hasn’t done it just for cosmetic reasons. Instead, they hope the innovation could help to cool buildings, reduce building energy demands, and even alleviate climate change.
As per Purdue, most white paints on the market get warmer rather than cooler as they reflect only 80% to 90% of sunlight. This new ultra-white paint changes that.
An infrared image (right) revealing how the whitest white paint is able to cool a board below ambient tempoerature. Image via Purdue University / Joseph Peoples
According to VICE, the idea of using white paint to lower building temperates dates back decades. However, new advances in nanotechnology have allowed engineers to work with new levels of reflectivity. Various scientists have developed coatings that can help achieve “daytime sub-ambient radiative cooling,” allowing building surfaces to remain cooler than the outside ambient temperature.
Now, with the whitest paint ever, the team, led by Xiulin Ruan at Purdue University, has pushed the envelope once again. According to a published study, the ultra-white coating made building surfaces 8°F (4.5°C) cooler than ambient temperatures at noon on a sunny day, and 19°F (10.5°C) cooler than its surroundings at night.
With this new invention, “on certain days in the summer, you probably don’t need to turn on your air conditioner at all,” Ruan told VICE, adding that the paint would “help offset a large portion of the cooling demand you would need.”
The paint is pigmented with barium sulfate instead of the titanium oxide that usual commercial paints use. Barium sulfate reflects UV light across all wavelengths, enabling it to remain cooler even on blistering hot days.
“We found that using barium sulfate, you can theoretically make things really, really reflective, which means they’re really, really white,” said Xiangyu Li, who worked on this project as a Purdue PhD student in Ruan’s lab.
Another key feature of the invention is the variable range of particle sizes used in the paint. The average size of particles in paint is estimated at 400 nanometers, but the team included particles that spanned several hundred nanometers in order to optimize its reflectivity across the broad spectrum of sunlight.
“In order to reflect the entire solar wavelength range, we put in a wider range of particle sizes,” Ruan explained.
The team is now working to reduce the width of the required paint coat. It hopes to decrease the layer needed from 200 microns thick to 50 to 100 microns, which would be more efficient commercially.
It is currently partnering with a large corporation towards commercializing the technology and are doing further testing to ensure its long-term reliability. The university has also filed patent applications for the formulation.
“Hopefully, in a year or two, we can start to manufacture these paints and make them available for customers to use,” Ruan told VICE.
Watch the engineers test (the previous version) of the ultra-white paint below.
[via Purdue University and VICE, images via Purdue University]
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