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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.
--AFP
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