Whitest white paint revealed: Time to meet blackest black?

Scientists revealed a new white paint that reflects 95.5% of sunlight that reaches its surface. This white paint is otherwise known as CaCO3-acrylic paint, or "Cooling Paint.: The creation of this white is in stark contrast with the material that's been called the "blackest black," AKA Vantablack, the most notorious and "darkest material" on Earth. Vantablack, developed by Surrey NanoSystems in the UK, absorbs up to 99.965% of light*, while CaCO3-acrylic paint reflects nearly that same percentage of (sun)light – imagine a checkerboard painted with the two!

Whitest White

CaCO3-acrylic paint was created in a science lab with the sun in mind. They developed this cooling paint for a wide variety of purposes, including (but not limited to) the coating of telecommunication equipment to prevent overheating.

ABOVE: Purdue researchers Xiulin Ruan (left) and Joseph Peoples use an infrared camera to compare the cooling performance of white paint samples on a rooftop. (Purdue University photo/Jared Pike)

Xiulin Ruan, professor at the School of Mechanical Engineering at Purdue University in Indiana, is one author of the study that developed this new cooling white. Ruan suggested that the white paint mix could benefit an array of industries and products, included but not limited to:

• Automobiles

• Data Centers

• Outdoor Electrical Equipment

• Military Infrastructure

• Food Storage

• Warehouses of many sorts

• Commercial Buildings

• Apartment Complexes

• Telecommunications Equipment (like 5G towers)

"This paint may even be used to combat climate change since it rejects sunlight and radiates heat into space," said Ruan in an interview with Science Daily.

This paint was developed from the beginning with ease of use in mind. Unlike Vantablack, which isn't technically available to the public and requires a special process to "paint" with, this cooling white paint is easy to make and easy to use. "Our paint is compatible with the manufacturing process of commercial paint," said Ruan, "and the cost may be comparable or even lower."

"It is a persistent task to develop a below-ambient radiative cooling solution that offers a convenient single-layer particle-matrix paint form and high reliability," said Ruan. "This is critical to the wide application of radiative cooling and to alleviate the global warming effect."

The original study was published in Cell Reports Physical Science with the title Full Daytime Sub-ambient Radiative Cooling in Commercial-like Paints with High Figure of Merit. This study was authored by Xiangyu Li, Joseph Peoples, Zhifeng Huang, Zixuan Zhao, Jun Qiu, and Xiulin Ruan. The paper was an open access publication, published with code DOI:10.1016/j.xcrp.2020.100221 on October 21, 2020.

The work to develop the cooling white in the study noted above was supported by two organizations. Air Force Office of Scientific Research through the Defense University Research Instrumentation Program, and the Cooling Technologies Research Center at Purdue University.

Blackest Black

Back in 2014, Surrey NanoSystems created the material mixture / process called Vantablack. This material is made with Vertically Aligned Nanotube Arrays that are applied to (or "grown") on a target surface using a chemical vapor deposition process. In the year 2016, they revealed an even blacker black, called Vantablack 2, that they suggested was blacker. They claimed the black was so black, the amount of light it reflected could not be determined, it was so insignificant.

They entered an exclusive agreement with artist Anish Kapoor to use the material for his art. The exclusive right to use Vantablack in fine art applications is limited to that field. Surrey NanoSystems worked with a variety of organizations to utilize Vantablack for products (like watches) and promotions (like they did for Call of Duty: Black Ops 4).

Since their deal with Kapoor, artists and designers have taken exception to the idea that the blackest black might only be available to ONE artist in the entire world. One such artist, Stuart Semple (and associates) made a point to create black paint (not the blackest black, but very, very black indeed) that's available to everyone in the world except Anish Kapoor.

Now we wait, and we watch, to see if the cooling white, the whitest white, becomes available for the masses. We shall see!