The world’s whitest paint – which keeps surfaces so cool that it will reduce the need for air conditioning – could soon be ready to put on grey nomad cars and caravans!
Last year, researchers at America’s Purdue University came up with a revolutionary paint which used nanoparticles of barium sulfate to reflect 98.1% of sunlight, cooling outdoor surfaces more than 4.5°C below ambient temperature.
However, there was a problem with its potential Big Lap application. To achieve that level of radiative cooling, scientists had to apply a layer of paint at least 400 microns thick … fine for painting something robust like the roof of a building, but not so good for use on ‘weight-conscious’ vehicles like caravans or motorhomes.
Now though, the Purdue University researchers have developed a new formulation that is thinner and lighter – and the future options are endless.
“I’ve been contacted by everyone from spacecraft manufacturers to architects to companies that make clothes and shoes,” said Xiulin Ruan, a Purdue professor of mechanical engineering and developer of the paint. “They mostly had two questions: Where can I buy it, and can you make it thinner?”
That’s why Ruan’s team began experimenting with other materials, pushing the limit of materials’ capability to scatter sunlight.
Their latest formulation is a nanoporous paint incorporating hexagonal boron nitride as the pigment, a substance mostly used in lubricants. This new paint achieves nearly the same benchmark of solar reflectance (97.9%) with just a single 150-micron layer of paint.
It means the newer paint weighs 80% less than the barium sulfate paint.
“Using this paint will help cool surfaces and greatly reduce the need for air conditioning,” Ruan said. “This not only saves money, but it reduces energy usage, which in turn reduces greenhouse gas emissions and, unlike other cooling methods, this paint radiates all the heat into deep space, which also directly cools down our planet.”
So, where can grey nomads buy the paint? “We are in discussions right now to commercialise it,” said Ruan. “There are still a few issues that need to be addressed … but progress is being made.”
