Consider this T-shirt: It can monitor your heart rate and breathing, analyze your sweat and even cool you off on a hot summer's day. What about a pillow that monitors your brain waves, or a solar-powered dress that can charge your phone or MP3 player? This is not science fiction - this is cotton in 2010.
The research group of Juan Hinestroza, assistant professor of Fiber Science, in collaboration with researchers at Italian universities has developed cotton threads that can conduct electric current like metal wire, yet remain light and comfortable enough to give a whole new meaning to multi-functional garments. This technology works so well that simple knots in this specially treated thread can complete a circuit - and a solar-powered dress with this technology will be featured at the annual Cornell Design League Fashion Show on Saturday, March 13 at Cornell University's Barton Hall.
Hinestroza and his colleagues at the universities at Bologna and Cagliari developed a simple technique to permanently coat cotton fibers with a combination of semiconductor polymers and nanoparticles. "We can definitively have traditional cotton fabrics becoming fully conductive, hence a great myriad of applications in the area of wearable electronics can be achieved," Hinestroza said.
"Our approach allows cotton to remain flexible, light and comfortable while being electronically conductive," Hinestroza said. "Previous technologies have achieved conductivity but the resulting fiber becomes rigid and heavy. More importantly our coatings are robust, hence making our yarns friendly to further processing such as weaving, sewing and knitting."
This technology is now beyond the theory stage. Hinestroza has partnered with Cornell Apparel Design student Abbey Liebman '10, who, inspired by these conductive yarns, designed a dress that uses flexible solar cells to power small electronics from a USB charger located in the dress waist. The charger can power a smartphone or an MP3 player, and the final electrical connections of the circuitry are made with the conductive cotton.
"Instead of conventional wires, we are using our conductive cotton to transmit the electricity -- so our conductive yarns become part of the dress," Hinestroza said. "Cotton has been called the fabric of our lives but based on these results, we can now call it 'The fabric of our lights.'"