Researchers have developed a groundbreaking bioplastic cooling film that can reduce surface temperatures by up to 9.2°C without consuming any electricity. The transparent film, made from cellulose and polylactic acid (PLA), works by reflecting incoming solar radiation while simultaneously emitting thermal infrared energy into outer space — a phenomenon known as radiative cooling. The innovation could significantly reduce air conditioning demand in buildings, particularly in tropical and subtropical climates.
Background: The Science of Radiative Cooling
Radiative cooling is a natural process that occurs when a surface emits more thermal energy than it absorbs. The challenge has been achieving daytime radiative cooling, where a material must reject enough incoming solar energy while still emitting strongly in the thermal infrared atmospheric transparency window (wavelengths of roughly 8 to 13 micrometers).
Previous radiative cooling materials relied heavily on synthetic polymers, metal oxide nanoparticles, or multilayer thin-film structures that are expensive and far from environmentally sustainable. The new bioplastic cooling film addresses these limitations by using bio-based, biodegradable raw materials. For background on PLA and cellulose as bioplastic feedstocks, see our Bio-based Polymers guide.
Key Details: How the Bioplastic Cooling Film Works
The research team engineered a composite film by combining cellulose nanocrystals with a PLA matrix. When dispersed within the PLA matrix, these nanocrystals create a hierarchical microstructure that scatters visible and near-infrared sunlight with high efficiency.
Both cellulose and PLA possess strong molecular absorption bands in the thermal infrared region that align well with the atmospheric transparency window. This means the film naturally emits thermal energy at precisely the wavelengths where Earth’s atmosphere is most transparent.
In outdoor field tests, the film achieved a sub-ambient temperature reduction of 9.2°C during peak daytime conditions. Its measured solar reflectance exceeded 95%, while its thermal infrared emissivity was above 90% within the critical 8-to-13-micrometer window.
The film is fully biodegradable. Both PLA and cellulose break down under industrial composting conditions. Our End-of-Life Options section explains how PLA-based products are processed through composting systems.
Industry Impact: From Lab to Rooftop
According to the International Energy Agency, space cooling accounts for roughly 16% of global electricity consumption in buildings. A passive cooling film that requires no electricity could dramatically reduce this energy burden.
The use of PLA and cellulose as base materials offers a clear pathway to cost-effective manufacturing. PLA is already produced at scales exceeding 400,000 tonnes per year globally, and cellulose is the most abundant biopolymer on Earth. The range of potential applications extends beyond buildings to include vehicles, cold-chain logistics containers, and even textiles.
What’s Next: Scaling and Commercialization
The research team is currently working on scaling the film manufacturing process from laboratory samples to roll-to-roll production. Key challenges include maintaining the precise nanocrystal dispersion, ensuring long-term durability under continuous UV exposure, and reducing production costs.
Several building materials companies and green technology investors have expressed interest in licensing the technology. Pilot installations on commercial buildings are expected within the next 18 to 24 months.
If commercialization succeeds, the bioplastic cooling film could become one of the most impactful applications of bio-based materials in the built environment. For more on how bioplastics are being used across diverse sectors, explore our Knowledge Zone.
