Light Me Up!

A lightweight, comfortable jacket that can generate the power to light up a jogger at night may sound futuristic, but UMass Amherst materials scientist Trisha Andrew could make one today. She and colleagues have invented a way to apply breathable, pliable, metal-free electrodes to fabric and off-the-shelf clothing so that it feels good to the touch yet transports enough electricity to power small electronics.

“Our lab works on textile electronics,” says Andrew, who trained as a polymer chemist and electrical engineer. “We aim to build up the materials science so that you can give us any garment you want—any fabric, any weave type—and turn it into a conductor. Such conducting textiles can then be built up into sophisticated electronics. One such application is to harvest body-motion energy and convert it into electricity in such a way that every move you make generates power.” Powering advanced fabrics that can monitor health data remotely is important to the military and is increasingly valued by the health care industry, she notes.

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Trisha Andrew, ChemisGenerating small electric currents through the relative movement of layers is called triboelectric charging, explains Andrew. Materials can become electrically charged as they create friction by moving against a different material, as happens when you rub a comb on a sweater. “By sandwiching layers of different materials between two conducting electrodes,” she explains, “a few microwatts of power can be generated when we move.”

Andrew and her colleagues have taken advantage of this new technique to make gloves that keep a hand’s fingers as warm as its palm.

“We took a pair of cotton gloves—regular, old-fashioned cotton cloth—and coated the fingers to allow a small amount of current to pass through, so that the fingers heat up,” says Andrew. “We chose to make a pair of gloves because the fingers require a high curvature that allows us to show that our material is really flexible.”  She adds that the glove is powered by a small coin battery that runs on nano-amps of current, not enough to pass through your skin or to hurt you.

 “Even when it’s completely dunked in water,” says Andrew, “our coating will not shock you, and our layered construction keeps the conductive cloth from coming into contact with your skin. We hope to have this reach consumers as a real product in the next few years. It’s ready to take to the next phase.”

Visit welab.umass.edu for more information.