Copyright Interesting Engineering
Researchers have developed a new type of material that can passively cool buildings and capture water directly from the air – all without energy input. Developed by researchers from the University of Sydney and start-up Dewpoint Innovations, the nano-engineered polymer paint-like coating could help tackle global water scarcity and cool buildings, reducing the need for energy-intensive systems. The 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. Technology advances the science of cool roof coatings The research team highlighted that this process creates ideal conditions for atmospheric water vapour to condense into droplets on the cooler surface, the way steam condenses on your bathroom mirror. “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 Neto from the University of Sydney Nano Institute and School of Chemistry. In the six-month-long outdoor study conducted on the roof of the Sydney Nanoscience Hub, dew could be collected over 32 percent of the year and so could provide a sustainable and predictable supply of water even in periods with no rain. Under optimum conditions, the coatings can harvest up to 390 mL of water per square metre each day – enough for a 12-square-metre surface to supply the daily drinking needs of one person, according to a press release. Design achieves high reflectivity “Our design achieves high reflectivity through its internal porous structure, delivering durability without the environmental drawbacks of pigment-based coatings,” said Dr Ming Chiu, the study’s lead author and Chief Technology Officer of Dewpoint Innovations. “By removing UV-absorbing materials, we overcome the traditional limit in solar reflectivity while avoiding glare through diffuse reflection. This balance between performance and visual comfort makes it easier to integrate and is more appealing for real-world applications.” Six-month outdoor trial The team also conducted a six-month outdoor trial and recorded cooling and water collection data minute-by-minute, confirming robust performance with no degradation under harsh Australian sun. Similar technologies have been shown to quickly deteriorate. The research team highlighted that beyond water harvesting, these coatings could help reduce urban heat island effects, lower energy needs for air-conditioning and provide climate-resilient water sources in regions facing growing heat and water stress. The work also challenges the assumption that dew collection only works in humid climates. The team also stressed that to bring the discovery from the lab to rooftops, Dewpoint Innovations is now developing a water-based paint formulation that can be applied using ordinary rollers or sprayers. “At Dewpoint, we’re proud to partner with the University of Sydney to bring this breakthrough in passive atmospheric water harvesting to life through advanced paint-based coatings,” said Perzaan Mehta, CEO of Dewpoint Innovations. “It’s a scalable, energy-free solution that transforms rooftops and remote infrastructure into reliable sources of clean water, helping address an urgent challenge of our time.”
