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"The idea is ingenious," says Min-Feng Yu, a mechanical-science and engineering professor at the University of Illinois at Urbana-Champaign. "It's like you have millions of nanogenerators outputting electricity simultaneously, each at maximum performance.".
The generator's ability to capture small movements makes it especially useful for powering biological sensors, Thundat says. Microscale sensors can be implanted in the body to measure such things as cancer biomarkers and glucose. But chemical batteries are bulky compared with the tiny sensors, and they have a limited lifetime. "Implanted sensors based on [the fiber nanogenerator] concept could use blood pressure or muscle movement for operation," Thundat says.
The Georgia Tech advance would not be possible without the simple but highly innovative process the researchers have used to make the fibers, Lieber points out. Zhong Lin Wang and his colleagues first cover a polymer fiber with a 100-nanometer-thick zinc oxide layer. They immerse the fiber in a reactant solution at 80 °C, which results in nanowires growing vertically from the surface. Then the researchers use a final trick to keep the nanowires firmly attached to the fibers while keeping the fibers flexible. They dip the fibers in tetraethoxysilane, a liquid used in weatherproofing and protective coatings. The tetraethoxysilane forms two coatings: one between the fiber and the zinc oxide layer, and another on top of the zinc oxide layer.
This tetraethoxysilane coating makes the fiber robust. The zinc oxide layer did not crack or peel off even when the fiber was twisted. The nanowires also stayed put after the researchers continuously brushed two fibers against each other for 30 minutes. The fibers will have to last even longer and have higher output power in order to be used practically, Wang says.
Power-generating shirts might still be out of reach for most. At this point, the fabric might be affordable for the military for use in tents and shoes, says Wang, but "it is probably too expensive for you and me to buy."
Researchers use a running rodent to test their device.
Researchers are experimenting with a novel nanowire material to power tiny biosensors and portable devices.
An array of zinc-oxide nanowires that generates current when vibrated with ultrasonic waves could provide a new way to power biological sensors and nanodevices.
Hopefully,this technology is being shared with the Pentagon and DARPA as they are looking for a
lightweight method of powering all the electronic equipment our troops are carrying now.
Even one could make a one-square-meter sheet of the said fabric, the amount of power (80 mW) it can generate is too small to be practically useful. A one-square-inch solar cell can generate > 200 mW power.
A twisted pair is not a "fabric"
This experiment used TWO single fibers twisted around one another. The experiment is clever, but its a long LONG way from a fabric or anything useful. Electrically connecting these hairy fibers is problematic. Making a fabric without destroying the delicate nanowires is problematic, because the nanowires are necessarily exposed so that they can be in contact. I really dont see how this concept can ever be useful or practical.
This article reminded me of an idea I had years ago, but doubted the manufacturing processes would be available for years. Perhaps this can now be done? Here's how it goes:
Couldn't a modification of this make electricity from the vibration of a magnet's molecules by making a sandwich of magnetized iron, and a thin matrix of microscopic coils and diodes? Wrap up the thin sheets of both into a cylinder so it can maintain a stronger magnetic field. Put output leads to power whatever you want. Lifetime battery?
You could call it a "free cell" or something. By experimenting with the microscopic wires & diodes in the matrix, you could adjust (at time of
manufacturing) the voltage per cell.
The higher the ambient temperature in a room, the more power this device would create. Might even cool a room down in a hot environment while at the
same time producing electricity.
Pass it on if you think it's worthwhile.
Vic Bradley
Vic@Vicshouse.com
Power from Fabrics and Brownian Motion
Shouldn't it be possible to take advantage of the evergy avaliable via Brownian Motion?
If this were to be a possibility why not create a set of curtains and place them in front of an open window. On a breezy day there would be enough wind to provide plenty of movement. Motion and energy and all of it passive. eyelet curtains
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patro7
3 Comments
very nice -- however....
I must say that this is impressive -- I have been following for a while and honestly thought that mechanical scavenging would be a few years off from the ultrasonic proof of concept. As with all nanotechnology though, I am concerned about the fabrication process and its scalability. It sounds as though this can lead to a continuous (certainly batch) process without too much heartburn -- but what do I know?
Here is the kicker -- suppose you have a power scavenging fiber; how do you interconnect? Interconnect for e-textiles has always been the long pole in the tent. On another note, I would not settle for power scavenging for the sake of personal electronics, there are much cooler things we can do here...
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dhall
1 Comment
Re: very nice -- however....
Why not cover a roof with these and let low speed wind currents provide the motion? Takes care of the wiring issue. The trick is to aggregate the output of many tiny sources, which this nanotube idea seems to provide. It could sell for a multiple of what solar panels cost per peak watt because these would provide power 24 hours per day, not just when the sun is out. Buildings have a lot of wall and roof space...
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