For an Energy Efficient Cool Roof, Try Poplar Leaves

The fast-growing poplar tree is starting to build up its cred as an all-around resource for the sustainable future, and its latest contribution is in the area of new cool roof technology. A research team in China has developed a waterproof coating that mimics the leaf’s highly efficient reflective properties, which could lead to a new generation of roof-cooling materials.

Poplar Leaves and Cool Roofs

“Cool roof” refers to the reflective properties of a roof that prevent it from absorbing excess heat. It also refers to the material’s level of emittance — its ability to release heat that it does absorb.  As recounted by Holly Sheahan for the Royal Society of Chemists, the research team from the Chinese Academy of Sciences observed that when the sun is strong, the poplar leaf turns itself over to expose its highly reflective, silvery underside.  The team developed long, hollow polymer fibers that mimic the properties of the leaf hairs, and the fibers were spun into a reflective film. So far, lab tests have been promising and the next step is to build more durability into the material.

Poplars and Sustainability

Partly because of their rapid growth pattern, poplars have become trees of interest in several different areas of sustainability research. Among these are green remediation, which includes the use of plants to extract pollutants from water. The poplar is also on the verge of breaking through as a biofuel crop, which also has the potential to double as a nature conservation or recreation area with appropriate forestry management. And then of course there’s the low-tech solution of using poplars as shade trees for buildings.