07/08/2025
China invented a paper-thin cooling film that drops temperatures by 15°C — without power
Chinese engineers at Zhejiang University have unveiled a paper-thin cooling film that can cool buildings, vehicles, and electronics by up to 15°C — without electricity, fans, or refrigerants. This breakthrough in passive radiative cooling could slash energy costs in hot climates and make off-grid temperature control a reality.
The film is made from a layered polymer structure coated with silicon dioxide nanoparticles, which reflect 95% of sunlight and simultaneously radiate absorbed heat into outer space through the mid-infrared spectrum. This dual-action process happens continuously — even under direct sunlight — allowing the material to maintain surfaces far cooler than ambient temperatures.
Tests on rooftops in 40°C heat showed the film reducing interior temperatures to 25°C without any power source. The material is waterproof, dust-resistant, and can be sprayed or rolled onto roofs, walls, car hoods, or even electronic devices to passively regulate heat.
Unlike traditional coatings, it’s also inexpensive and scalable, costing less than $2 per square meter to manufacture. It doesn’t degrade in sunlight, works year-round, and is compatible with urban surfaces like asphalt, concrete, or metal.
Cities struggling with urban heat islands, data centers battling overheating, and homes in off-grid or disaster-prone zones could soon be covered in this self-cooling film. It’s one of the first materials to combine affordability, sustainability, and engineering elegance — without a plug.
