Imagine wearing a shirt that can power an mp3 player, cell phone, and monitor your heart beat, brain waves and more. U.S. and Italian scientists have invented a fabric that can conduct electricity but that also can be made into light, comfortable clothing.
The new, high-tech fabric contains cotton threads coated with a thin layer of semiconductor polymers and nanoparticles which conduct electricity like metal wires.
But one of the developers of the new fabric, Juan Hinestroza of Cornell University in New York says at first glance it's hard to tell the difference between plain cotton and cloth sewn with the conductive thread.
"They will bend the same, they will drape the same, they will feel the same. Now if I put electricity through one of them, then you will see the difference," he said.
During the day, Hinestroza says tiny solar power cells embedded in the fabric collect energy and store it in a device similar to a double-A battery. The conductive thread, which is woven through the cotton fabric, is attached to the battery and power is discharged through a USB (flash drive) interface. He says a simple knot in the conductive thread completes the circuit from energy storage to discharge.
Hinestroza says small devices like mp3 players and cell phones can be powered by attaching them to the USB hook-up, also hidden in a garment seam. The portable system means no electrical outlets are needed to keep the devices charged.
Hinestroza says the conductive thread is so pliable and durable it can be sewn into any fabric with a sewing machine.
Scientists are investigating other applications for conductive fabric, such as monitoring critical bodily functions.
"At this moment, we are looking at using the fibers into [as] electrodes that can monitor heart rates but that's also part of the clothing, so there won't be any changes in performance or comfort. In fact, the user will never notice that you have the conductive yarn that is different from the other cotton," he said.
Hinestroza says monitoring heart rate and other vital bodily functions requires that the conductive threads be woven into dense grids in special, flexible fabrics. These patches of conductive material can then act as electrical sensors to detect the vibration from a pulse and breathing, or as electrodes to monitor brain waves like an EEG machine (electroencephalogram).
Hinestroza says it's up to private companies now to develop specific applications for conductive fabric.
"It will open a complete new way of possibilities of embedding sensors in bedding sheets, or in clothing or in shoes or in curtains, carpets. And the sensors will be part of the item of the fabric and that's the main difference," he said. "Instead of having a foreign object acting as a sensor, the sensor is a fiber and it's a natural fiber. It's not a synthetic one."
While it's too soon to predict when the first high-tech garments will be available, Cornell University's Juan Hinestroza expects the first of many applications using electrically conductive thread will be ready for the market in the near future.