Move over, Styrofoam. Scientists have designed a heat-insulating material made from wood that is both light and strong and made entirely from tiny, stripped-down wood fibers.
The so-called nanowood, described in the journal Science Advances, could one day be used to make more energy-efficient buildings. It's cheap and biodegradable, too.
"Nature is producing this kind of material," said senior author Liangbing Hu, a materials scientist and engineer at the University of Maryland in College Park.
Managing heat is a major issue in the cities we build. It's hard to keep heat indoors in the winter and keep it outdoors in the summer. The insulating materials currently in use are often very expensive to make, both in terms of money and of energy. They're not usually biodegradable and ultimately contribute to our growing landfills. So scientists have been trying to come up with cheaper, more environmentally friendly options.
Hu has been probing the properties of nanocellulose, nanometer-scale versions of cellulose, the tough carbohydrate in the cell walls of plants that allows tree trunks to grow strong and tall. At these incredibly small scales, cellulose fibers can take on remarkable characteristics, including a strength-to-weight ratio that's about eight times that of steel.
Hu and his team have already developed a strong, dense material they called super wood, in part by removing some of the wood's lignin – a complex polymer that holds cellulose in the wood together, almost like glue – and hemicellulose, another component of woody tissue.