PEDOT-coated yarns that act as 'normal' wires transmit electricity from a wall outlet to an incandescent lightbulb. Materials scientist Trisha Andrew at UMass Amherst and colleagues outline in a new paper how they have invented a way to apply breathable, pliable, metal-free electrodes to fabric and off-the-shelf clothing so it feels good to the touch and also transports electricity to power small electronics. Harvesting body motion energy generates power. Image credit: UMass AmherstA lightweight jacket capable of generating enough power to light up a nighttime jogger is now a reality according to materials scientist Trisha Andrews of the University of Massachusetts.

Applying breathable, pliable, metal-free electrodes to material and off-the-shelf clothing has made it possible, according to researchers, to transport enough electricity to power small electronics.

“Our lab works on textile electronics. We aim to build up the materials science so 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 time you move, it generates power," said Andrews.

Called triboelectric charging (generating small electric currents through relative movement of layers), materials moving against a different material create friction and become electrically charged. “By sandwiching layers of different materials between two conducting electrodes, a few microwatts of power can be generated when we move," she added.

Published in Advanced Functional Materials, Andrews and her team describe using a vapor deposition method to coat fabrics with a conducting polymer (PEDOT) creating a conducting fabric that is resistant to stretching and wear.

"You'd be amazed how much stress your clothes go through until you try to make a coating that will survive a shirt being pulled over the head. The stress can be huge, up to a thousand newtons of force. For comparison, one footstep is equal to about 10 newtons, so it's yanking hard. If your coating is not stable, a single pull like that will flake it all off. That's why we had to show that we could bend it, rub it and torture it. That is a very powerful requirement to move forward," added Andrews.

The researchers say the invention overcomes the obstacle of power-generating electronics mounted on plastic, veneer-like fibers making garments heavier and/or less flexible than off-the-shelf clothing.

In addition to power generating fabric, Andrews and her team are working on a wearable heart rate monitor (an off-the-shelf bra outfitted with eight monitoring electrodes) and turning any off-the-shelf garment into a solar cell to power small electronic devices.