Cellulose, the most prevalent biological material on the planet, is receiving significant attention of late. The complex carbohydrate makes up the essential structure of plant cell walls and its fibers are used to make a variety of products including paper, synthetic textiles, plastic, coatings, and films. In some cases, the fibers are chemically modified using methods that employ toxic chemicals. But researchers at the University of Alabama have found a more sustainable fabrication method that allows cellulose fibers from natural materials such as cotton and wool to bind with conductive polymers for use as electrical conductors in smart textiles and fabrics.
The researchers worked with a conductive polymer called polypyrrole, which is conventionally difficult to bind with natural fibers. As a result, the fibers are dipped in an acidic solvent to facilitate binding, which has the side effect of weakening them. The research team's newly patented method processes the fibers in liquid salts, which strengthen the fibers and enhance the conductivity of the final composite. The discovery is critical, the researchers say, because it opens up traditionally weaker fibers such as those of cotton and wool for use as conductive polymer composites.
"A lot of effort has been made into making cellulose fibers conductive through chemical methods that, from a manufacturing standpoint, are not environmentally friendly," said Anwarul Haque, an associate professor of aerospace engineering and mechanics, in a UA press release. "Our process does away with the use of methanol through the novel use of ionic liquids, which, by their very nature, have a low volatility that essentially eliminates environmental release pathways exhibited by methanol."
In addition to smart clothing that monitors body functions with enhanced electronic features, the new material could be used in other types of textiles such as upholstery, fabric panels, wall coverings, and sunshades. Not only could these fabrics be electrically augmented with sensing and communicating capabilities, but their manufacture would also be guilt-free.
Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.