A novel roof coating developed by researchers at the University of Sydney and Dewpoint Innovations offers a dual benefit of cooling homes and generating fresh water from the air. This innovative paint-like polymer reflects nearly all sunlight while passively collecting dew, achieving remarkable cooling effects of up to 6 °C (approximately 11 °F) indoors. It can produce substantial amounts of water, making it a promising solution to address the growing challenges of climate change and water scarcity.
The nano-engineered coating has demonstrated impressive results in a six-month outdoor trial at the Sydney Nanoscience Hub, where it successfully collected dew for over 30% of the year, yielding up to 390 mL of water per square meter daily. This translates to nearly 4.7 liters (around 1.25 US gallons) per day from a 12-square-meter roof area. While it is a supplementary water source alongside traditional rainwater collection, it could significantly meet residential water needs, especially in arid regions.
Chemically, the coating contains polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP) and utilizes a porous structure to reflect sunlight without relying on UV-absorbing pigments. This innovative structure ensures durability and high performance while minimizing glare, which suggests its practical application in various settings. The surface design enables dew droplets to collect efficiently and be directed to collection points, which could be leveraged for irrigation, cooling systems, or even hydrogen production.
Chiara Neto, a professor leading the research, noted that the technology addresses critical freshwater needs, especially in areas facing increased environmental stress. With further scaling efforts underway, Dewpoint Innovations is excited to introduce a user-friendly, water-based formulation that can be easily applied to rooftops with standard painting tools. The potential commercial release of this environmentally friendly paint promises to revolutionize how urban and rural areas leverage rooftop spaces, providing a reliable and sustainable water source.