SYDNEY, Nov. 3 (Xinhua) -- Scientists in Australia have developed a nanoengineered polymer paint-like coating that can passively cool buildings and capture water directly from the air, all without energy input.
The invention could help tackle global water scarcity and help cool buildings, reducing the need for energy-intensive systems, according to a statement released Monday by Australia's University of Sydney, which conducted the research with start-up Dewpoint Innovations.
The research team created a porous polymer coating that reflects up to 97 percent of sunlight and radiates heat into the air, keeping surfaces up to six degrees cooler than the surrounding air even under direct sun, it said.
This process creates ideal conditions for atmospheric water vapor to condense into droplets on the cooler surface, "the way steam condenses on your bathroom mirror," it added.
"This technology not only advances the science of cool roof coatings but also opens the door to sustainable, low-cost and decentralized sources of fresh water, a critical need in the face of climate change and growing water scarcity," said Professor Chiara Neto from the University of Sydney Nano Institute and School of Chemistry.
In a six-month outdoor study on the Sydney Nanoscience Hub rooftop, the coating collected dew over 32 percent of the year, harvesting up to 390 ml of water per square meter daily, enough for a 12-square-meter surface to supply the daily drinking needs of one person.
Unlike traditional white paints, the polymer relies on internal porous structure rather than ultraviolet-reflective pigments such as titanium dioxide, improving durability and reducing glare, according to the study, published in Advanced Functional Materials.
"Imagine roofs that not only stay cooler but also make their own fresh water, that's the promise of this technology," Neto said. ■
