Scientists create world's whitest paint; eliminates need for air conditioning

In a breakthrough invention, scientists at Purdue University, Indiana, United States, have created the whitest paint in the world that could dramatically reduce or even eliminate the need for air conditioning. The invention of the whitest paint, aimed to counter global warming, had earned the prestigious Guinness World Records title, which will appear in the 2022 edition. The whitest paint ever went for sale starting Thursday, Sept. 16. Researchers partnered with a company to scale up the paint and put it on the market after the Patent applications were filed through the Purdue Research Foundation Office of Technology Commercialisation. 

“When we started this project about seven years ago, we had saving energy and fighting climate change in mind,” said Xiulin Ruan, a professor of mechanical engineering at Purdue, in a podcast episode of “This Is Purdue.” Furthermore, he added, that the idea behind the invention was creating a whitest paint that would reflect sunlight away from a building keeping it cool. 

Ruan invented the paint with a team of graduate students, with the aim that the paint had to be really reflective and extraordinarily white in order to bounce back 98.1 per cent of solar radiation from homes and at the same time emit the infrared heat. “Because the paint absorbs less heat from the sun than it emits, a surface coated with this paint is cooled below the surrounding temperature without consuming power,” said Xiulin Ruan. The typical commercial white paint available in the market actually gets warmer than cooler, the researchers revealed, adding that these paints reflect only 80-90 per cent of sunlight, and can’t make surfaces cooler than their surroundings. 

“Using this new paint formulation to cover a roof area of about 1,000 square feet could result in a cooling power of 10 kilowatts,” researchers at Purdue said in a paper published in American Chemical Society [ACS] Publication on September 17. “That’s more powerful than the air conditioners used by most houses,” lead researcher Ruan said.

Invention technique dates back to'1970s'

The technique employed by the scientists in the invention of this paint dates back to the 1970s when the developers focused on making a radiative cooling paint so white as it shall be a feasible alternative to traditional air conditioners. At Purdue, Ruan’s lab considered over 100 different materials to make the whitest paint ever and later, narrowed it to approximately 10. Researchers then tested about 50 different formulations for each material to achieve the desired result. 

“Two features make this paint ultra-white: a very high concentration of a chemical compound called barium sulfate – also used in photo paper and cosmetics – and different particle sizes of barium sulfate in the paint,” researchers at Purdue explained in a statement on University’s website. They further explained that the wavelength of sunlight that scatters from each of the particles depended on its the paint’s size, so a wider range of particle sizes allows the paint to scatter more of the light spectrum from the sun. “There is a little bit of room to make the paint whiter, but not much without compromising the paint,” said the scientists.