Researchers at the University of Sydney and Dewpoint Innovations have introduced an innovative nanoengineered polymer coating that functions like paint, providing passive cooling for buildings while harvesting water from the atmosphere without requiring energy. This groundbreaking technology has the potential to address global water shortages and reduce reliance on energy-intensive cooling systems.
Led by Professor Chiara Neto, the research team created a porous polymer coating that reflects up to 97 percent of sunlight and dissipates heat, keeping surfaces as much as six degrees cooler than the ambient air even in direct sunlight. This cooling effect facilitates the condensation of atmospheric water vapor into droplets on the surface, similar to the way steam collects on a bathroom mirror.
Professor Neto, affiliated with the University of Sydney Nano Institute and the School of Chemistry, emphasized the broader implications of this discovery, stating, “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.”
In a six-month outdoor experiment conducted at the Sydney Nanoscience Hub, the technology successfully collected dew for over 32 percent of the year, offering a reliable source of water even during dry spells. Under optimal conditions, the coating can yield as much as 390 mL of water per square meter daily, sufficient to meet the daily drinking requirements of one person from a 12-square-meter area.
The findings, published in Advanced Functional Materials, demonstrate the feasibility of integrating passive cooling and atmospheric water capture into a paint-like material for widespread application. This versatility could make the technology beneficial across various industries, such as agriculture for high-value crops, animal hydration, misting cooling systems, and hydrogen production, given that water is essential for electrolysis in hydrogen generation.
Unlike conventional white paints, the new porous coatings, composed of polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP), do not depend on UV-reflective pigments like titanium dioxide. Dr. Ming Chiu, the study”s lead author and Chief Technology Officer at Dewpoint Innovations, noted, “Our design achieves high reflectivity through its internal porous structure, delivering durability without the environmental drawbacks of pigment-based coatings.” He added that eliminating UV-absorbing materials helps surpass traditional limits in solar reflectivity while minimizing glare through diffuse reflection, enhancing both performance and visual comfort for practical applications.
Throughout the outdoor trial, the team gathered minute-by-minute data on cooling and water collection, confirming the coating”s resilience against the harsh Australian sun, in contrast to similar technologies that tend to deteriorate quickly. Beyond water collection, these coatings can mitigate urban heat island effects, lower cooling energy demands, and create resilient water sources in areas facing increasing heat and water scarcity.
Professor Neto, who is also part of the University of Sydney Net Zero Institute, pointed out that dew collection is not solely effective in humid climates. “While humid conditions are ideal, dew can form even in arid and semi-arid regions where nighttime humidity increases. This technology is not intended to replace rainfall but to supplement it, providing water when other sources are scarce.”
To transition this discovery from laboratory research to practical use, Dewpoint Innovations is developing a water-based paint formulation that can be easily applied with standard 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,” stated 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, addressing an urgent challenge of our time.”
With over two million homes in Australia already utilizing rainwater collection systems, Professor Neto believes that roofs capable of dew collection could enhance existing water solutions. “Imagine roofs that not only stay cooler but also generate their own fresh water – that”s the promise of this technology,” she concluded.
The innovation from Neto”s research group was licensed to Dewpoint Innovations in 2022. Its commercial application marks a significant advancement toward scalable, sustainable solutions for passive water collection and cooling, with diverse potential applications in urban infrastructure, agriculture, and remote communities.
Chiu, M. et al, “Passively cooled paint-like coatings for atmospheric water capture,” Advanced Functional Materials, 2025, DOI: 10.1002/adfm.202519108. The authors declare a financial interest in Dewpoint Innovations Pty Ltd, which holds the patent for this work. They acknowledge funding from the University of Sydney Nano Institute. Dewpoint Innovations supported the outdoor prototypes” construction, and Dr. Jimmy Leung contributed to their maintenance. The authors also thank the Australian Centre for Microscopy & Microanalysis for their imaging facilities and technical support.
