Biodegradable cooling film slashes energy use 20% without power

Scientists from Zhengzhou University and the University of South Australia have developed the world’s first biodegradable cooling film capable of passively reducing surface temperatures by up to 9.2°C without electricity. Made from polylactic acid (PLA), a plant-based biodegradable plastic, the film achieves this cooling by reflecting 98.7% of solar radiation and enabling internal heat to radiate directly into outer space. This passive cooling effect can reduce energy consumption for air conditioning by more than 20% in hot urban environments, offering a sustainable alternative to conventional, energy-intensive cooling systems. The metafilm features a porous, bi-continuous structure with ultra-low thermal conductivity (0.049 W/m·K) and high durability, maintaining performance even after exposure to harsh acid solutions and prolonged UV radiation. Its robustness is attributed to a 29.7% stereocomplex crystal content, which enhances thermal and chemical stability. Computer simulations indicate significant potential energy savings in cities like Lhasa, China, and the technology