Scientists in China have made a reflective coating with a structure that mimics the underside of a poplar tree leaf. Researchers from the Chinese Academy of Sciences, Beijing, mimicked the structure of the leaf’s lower surface using polymers spun into reflective films consisting of long, hollow uniform fibers. The underside of the poplar leaf is better at reflecting light than the top. Because of the cool roof effect in which a layer of hairs on the underside deflects the light resulting in less heat penetrating the leaf. The leaf actually turns over in strong sunlight to reveal the underside and as the light is being reflected rather than absorbed, the leaf appears white. The coating that was created is both reflective and waterproof, making it ideal for use on a building envelope component.