Colorful films could help buildings, cars keep their cool

Posted On: 2023-08-02

Scientists report an eco-friendly alternative to air conditioning — a plant-based film that gets cooler when exposed to sunlight and comes in a variety of textures and bright, iridescent colors. The material could someday keep buildings, cars and other structures cool without requiring external power. Colored pigments, by definition, absorb specific wavelengths of sunlight and only reflect the colors we see, causing undesirable warming effects in the process. However, the group found that cellulose nanocrystals, which are derived from the cellulose found in plants, could be made into iridescent, colorful films without any added pigment. A square meter of the cellulose nanocrystal film generated over 120 Watts of cooling power, rivaling many types of residential air conditioners.