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World Record: Four-Centimeter-Long Carbon Nanotube
colonist writes "University of California scientists at Los Alamos National Laboratory and chemists from Duke University have recently grown a four-centimeter-long, single-wall carbon nanotube (SWNT): a new world record. Previous SWNTs were a few millimeters long. Yuntian Zhu and his colleagues used a process called 'catalytic chemical vapor deposition' from ethanol (alcohol) vapor. From their abstract: 'Our results suggest the possibility of growing SWNTs continuously without any apparent length limitation.' Zhu: 'although this discovery is really only a beginning, the continued development of longer length carbon nanotubes could result in nearly endless applications. Actually, the potential uses for long carbon nanotubes are probably limited only by our imagination.'"
1/10th of a centimeter is a millimeter. 1/10000th of a centimeter is a micrometer. Anyway, at 11um/s, 4cm takes an hour. Geosynch takes a hundred thousand years. Better get started.
Finally! A year of moderation! Ready for 2019?
Answering my own question here, but it appears the article is correct. Metallic in this case is refering to the crystaline structure that the carbon forms. This gives the nanotube certain properties that are 'metallic' - High tensile strength, ductile, flexible, etc.
Yeah, that's usually what we mean by metallic. :) Atoms have funny properties when they're arranged into specific structures. Just think of the differences between graphite (good conductor, relatively speaking) and diamond (very good insulator).
:)
The reason why metals are the way they are is because they have large numbers of free electrons in their matrix. Nanotubes are basically just graphite rolled up into a tube, and so they have an electronic structure which is more similar to metals than, say, diamonds or a lump of coal.
Interestingly, hydrogen can also be metallic (when highly compressed--so-called liquid metallic hydrogen), which means that there are no exceptions to the first column of the periodic table being metals after all.
I was under the impression that this earlier UT "long nanotube" was actually made by braiding smaller nanotubes together into a larger "strand". The difference here is that the 4cm world record is for a single tube, no braiding things together.
11*43+456^2
Because, as discussed above, this is not a solid tube. Your own quote says:
Baughman's team spins fibers made of carbon nanotubes and.
The greater the length of nanotube, the less epoxy needed to hold the woven elevator ribbon together. Since the epoxy weighs a lot more than the nanotube, this is a good thing and reduces load on the ribbon from its own weight
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Smoke is where the first place that buckyballs and nanotubes were discovered. All we are doing is making normal smoke a little chunkier.
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Well long natural cotton fibers happen to be about the same length, for a growth rate of about 4cm per year. Which means we can grow these nanotube fibers almost ten thousand times faster than cotton fibers!
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