It combines high solar reflectance, low thermal conductivity, and biodegradability for cooling buildings, vehicles, farms, and even medical applications.
A team from Zhengzhou University and the University of South Australia has created a groundbreaking biodegradable cooling film that can reduce surface temperatures by up to 9.2°C without using any electricity. This metafilm works by reflecting 98.7% of solar radiation while simultaneously allowing a building's internal heat to escape directly into space, a process known as passive radiative cooling. This technology offers a sustainable alternative to energy-intensive air conditioning and could help cut cooling energy use by more than 20% in hot cities.
The film is innovatively made from polylactic acid (PLA), a biodegradable plastic derived from plant sources like corn. Its effectiveness and durability stem from a unique porous structure created through a low-temperature fabrication process, which also gives it ultra-low thermal conductivity. Crucially, this material overcomes the limitations of earlier biodegradable coolers, proving robust enough to maintain a significant cooling effect even after exposure to strong acid and prolonged UV radiation.
The researchers emphasise that this scalable and environmentally friendly technology has vast potential. Beyond building cooling, it could be applied in transportation, agriculture, electronics, and even biomedical fields such as smart dressings. As global temperatures and energy demands rise, this biodegradable metafilm presents a promising, clean solution to the growing challenge of staying cool.
