Scientists have developed a groundbreaking paint-like coating capable of harvesting water directly from the atmosphere, while simultaneously reducing surface temperatures. This technology, a collaboration between the University of Sydney and start-up Dewpoint Innovations, represents a potential solution for water scarcity and urban heat mitigation, particularly in regions facing climate change impacts.
How the Coating Works: Passive Cooling and Water Condensation
The coating, constructed from a porous polymer called polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP), employs a unique passive cooling mechanism. It reflects up to 97% of sunlight and efficiently radiates heat into the surrounding air, keeping surfaces up to 6 degrees Celsius cooler than the ambient temperature. This cooling effect creates conditions conducive to atmospheric water vapor condensation, similar to how steam condenses on a bathroom mirror.
Sustainable Water Harvesting Potential
“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,” explained University of Sydney’s Professor Chiara Neto.
Results from Field Testing
A six-month outdoor study conducted on the roof of the Sydney Nanoscience Hub demonstrated the coating’s effectiveness. Researchers were able to collect dew for over 32% of the year, indicating a reliable and predictable water supply even in the absence of rainfall. Under optimal conditions, the coating can harvest up to 390 mL of water per square meter daily—sufficient to meet the daily drinking needs of one person on a 12-square-meter surface.
Key Advantages Over Traditional White Paints
Unlike conventional white paints that rely on ultraviolet-reflective pigments like titanium dioxide, this porous coating achieves high reflectivity through its internal structure. “Our design achieves high reflectivity through its internal porous structure, delivering durability without the environmental drawbacks of pigment-based coatings,” said Dr. Ming Chiu, chief technology officer of Dewpoint Innovations. By eliminating UV-absorbing materials, the technology overcomes limitations in solar reflectivity while avoiding glare through diffuse reflection—creating a visually comfortable and practical solution.
Robust Performance and Broad Applications
The research team rigorously monitored the coating’s performance throughout the trial, recording data minute-by-minute and confirming its robustness under harsh Australian sunlight without degradation. Beyond its water harvesting capabilities, the coating holds promise for diverse industrial applications: providing water for livestock, supporting horticulture of high-value plants, improving cooling through misting, and even aiding in hydrogen production.
Addressing Urban Heat and Expanding Possibilities
This innovative technology extends beyond water collection. The cooling effect of the coating has the potential to reduce urban heat island effects and lower energy consumption for air conditioning. Crucially, the research challenges the assumption that dew collection is limited to humid climates. “It’s not about replacing rainfall but supplementing it — providing water where and when other sources become limited,” Professor Neto noted.
The team’s findings, published in Advanced Functional Materials, highlight a significant step towards climate-resilient water solutions and sustainable cooling strategies.
This new paint-like coating is a practical solution that can address both water scarcity and the rising temperatures in urban areas – a significant advancement for sustainability
