In a groundbreaking achievement, scientists at Purdue University have developed the whitest white paint ever made, so reflective that it can cool surfaces significantly, even under the scorching sun. This ultra-white paint, first introduced in 2020, has recently been enhanced to reflect a staggering 98.1 percent of sunlight, earning it a spot in the Guinness World Records as the whitest paint ever created.
While this scientific feat may sound like an aesthetic pursuit, the motivation behind it is far more profound. “We weren’t really trying to develop the world’s whitest paint,” said Xiulin Ruan, a Purdue professor of mechanical engineering who led the research. “We wanted to help with climate change, and now it’s more of a crisis, and getting worse. We wanted to see if it was possible to help save energy while cooling down the Earth.”
A Cool Solution to a Warming Planet
The potential impact of this ultra-white paint is significant. By reflecting nearly all sunlight that hits it, the paint can keep surfaces cool to the touch even during the hottest parts of the day. For instance, a surface coated with this paint can be up to eight degrees Fahrenheit cooler than the surrounding air temperature in the afternoon, and the difference can reach up to 19 degrees Fahrenheit at night.
This cooling effect could prove revolutionary in urban areas, where the “urban heat island” effect—caused by buildings absorbing more heat than natural landscapes—leads to elevated temperatures. Painting rooftops and building exteriors with this whitest white paint could help counteract this phenomenon, potentially reducing the need for air conditioning and lowering energy consumption.
The Science Behind the Whitest White
The journey to create this super-reflective paint was no small task. The initial version of the paint, which reflected 95.5 percent of sunlight, was made using calcium carbonate particles. However, after six years of research and testing over 100 different materials, the Purdue team discovered that barium sulfate was the key to pushing reflectivity even further. Barium sulfate’s reflective properties are so powerful that a higher concentration of its particles increases the paint’s whiteness, though too much of it can cause the paint to crack.
This scientific advancement draws parallels with other record-setting materials, such as Vantablack, known as the “blackest black,” which absorbs 99.965 percent of light. While Vantablack is made from carbon nanotubes, the ultra-white paint’s secret lies in the unique composition of barium sulfate.
Beyond Buildings
The potential applications for this paint are vast, extending beyond just buildings. “I’ve been contacted by everyone from spacecraft manufacturers to architects to companies that make clothes and shoes,” Ruan said. These industries are eager to harness the cooling power of the whitest white paint, though many have asked for a thinner version suitable for their specific needs. In response, Ruan’s team has been working on a lightweight formula that could be used on cars and other surfaces.
Although the paint is not yet commercially available, with a release expected in about a year, the Purdue team is collaborating with a paint manufacturing company to refine the product further. Their goals include enhancing the paint’s durability, making it more resistant to dirt, and even developing other colors that incorporate the ultra-white base to improve their reflective properties.
The Future of Cooling Technology
While the whitest white paint is a remarkable tool for cooling, its widespread use could have a tangible impact on global temperatures. A 2019 study published in the journal Joule suggested that to stop global temperatures from rising, one to two percent of the Earth’s surface would need to be covered with a reflective material like this paint—an area just over half the size of the Sahara Desert.
In the meantime, the whitest white paint offers a glimpse into the future of sustainable cooling technologies. By reducing the need for air conditioning, this innovation could help cut down on energy consumption and greenhouse gas emissions, making it a small but significant step in the fight against climate change. As Ruan and his team continue to refine their creation, the world eagerly awaits the impact this ultra-white paint will have on our environment and daily lives.