US researchers have created a nano-fiber textile that harvests energy from movement, paving the way for clothing that could one day power an iPod or other wearable electronic devices, according to a study published Wednesday.
Using the same mechanical principle as a self-winding watch, but on scale measured in billionths of a meter, tiny nano-generators can scavenge "wasted" energy from sound waves, vibrations, or even the human heart beat.
The fibers, developed by a team of scientists at the Georgia Institute of Technology led by Zhong Lin Wang, are covered with pairs of zinc oxide nanowires that produce tiny pulses of electricity in response to friction.
"The two fibers scrub together just like two bottle brushes with their bristles touching," converting the mechanical motion into electrical energy, explained Wang.
"Many of the devices could be put together to produce a higher output," he said.
This method of generation energy from friction is called the "piezoelectric effect."
The fibers could also be woven into curtains, tents or other structures to capture energy from wind motion, sound vibrations or other mechanical energy, according to the study, published in the British journal Nature.
The human body contains many sources of energy that could drive nanogenerators, including blood flow pumped by the heart, exhalation from the lungs, and walking.
Even the act of typing on a computer is a potential source of nano-scale energy.
So far, Wang and his colleagues have made more than 200 of the microscopic nano-generators. The fibers assemblies were each tested for 30 minutes to check durability and power production.
Other kinds of nano-generators driven by scavenged energy aim to power biosensors to monitor a patient's glucose levels, strain sensors for bridges, and environmental sensors to detect toxins.
There remains at least one significant problem before Wang's nano-fibers can become part of our daily wardrobes.
Zinc oxide is sensitive to water, which means that clothes made from these fibers could never be washed, the study said.