Innovative Paint-Like Coating Captures Water Directly from Thin Air
Scientists from the University of Sydney and start-up Dewpoint Innovations have created a porous polymer coating that reflects up to 97% of sunlight and radiates heat into the air, keeping surfaces up to 6 degrees cooler than the surrounding air, even in direct sunlight. This process creates ideal conditions for atmospheric water vapor to condense into droplets on the cooler surface, similar to how steam condenses on your bathroom mirror.
Experimental installation on the roof of the Sydney Nanoscience Hub. Image credit: University of Sydney.
“This technology not only advances the science of cold roof coverings, but also opens the door to sustainable, low-cost and decentralized fresh water sources – a crucial need in the face of climate change and increasing water scarcity,” said Professor Chiara Neto from the University of Sydney.
As part of a six-month outdoor study carried out on the roof of the Sydney Nanoscience Hub, dew could be collected for 32% of the year and could thus provide a sustainable and predictable water supply, even in periods without rain.
Under optimal conditions, the coverings can collect up to 390 ml of water per square meter each day, enough for an area of 12 m². surface to meet a person’s daily drinking needs.
The study shows that passive cooling and atmospheric water capture can be integrated into a paint-like material for large-scale use.
Larger collection areas mean the paint could be versatile in industry: water for animals, for horticulture of high-value plants, for use in misting cooling or for use in hydrogen production.
Unlike traditional white paints, porous polyvinylidene fluoride-co-hexafluoropropene (PVDF-HFP) coatings do not rely on ultraviolet-reflecting pigments such as titanium dioxide.
“Our design achieves high reflectivity through its internal porous structure, providing durability without the environmental drawbacks of pigment-based coatings,” said Dr. Ming Chiu, Chief Technology Officer of Dewpoint Innovations.
“By removing UV-absorbing materials, we overcome the traditional limitation of solar reflectivity while avoiding glare from diffuse reflection. »
“This balance between performance and visual comfort makes integration easier and more attractive for real-world applications. »
During the six-month outdoor trial, researchers recorded minute-by-minute cooling and water collection data, confirming robust performance without degradation under the Australian sun. Similar technologies have been shown to deteriorate quickly.
Beyond water harvesting, these coatings could help reduce the effects of urban heat islands, reduce energy requirements for air conditioning, and provide climate-resilient water sources in regions facing increasing heat and water stress.
“The research also challenges the assumption that dew collection only works in humid climates,” Professor Neto said.
“Although humid conditions are ideal, dew can form even in arid and semi-arid regions where nighttime humidity increases.”
“It is not about replacing rainfall, but supplementing it, providing water where and when other sources become limited. »
The team’s work was published on October 30 in the journal Advanced functional materials.
_____
Ming Chiu and others. Passively cooled paint-like coatings for capturing atmospheric water. Advanced functional materialspublished online October 30, 2025; doi: 10.1002/adfm.202519108
