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Science Technology

How To Cut a Nanotube? Lots Of Compression 38

An anonymous reader writes "A pipefitter knows how to make an exact cut on a metal rod. But it's far harder to imagine getting a precise cut on a carbon nanotube, with a diameter 1/50,000th the thickness of a human hair. In a paper published this month in the British journal Proceedings of the Royal Society A, researchers at Brown University and in Korea document for the first time how single-walled carbon nanotubes are cut, a finding that could lead to producing more precise, higher-quality nanotubes. Such manufacturing improvements likely would make the nanotubes more attractive for use in automotive, biomedicine, electronics, energy, optics and many other fields."
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How To Cut a Nanotube? Lots Of Compression

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  • The size of a hair is easy to imagine. The size of half a hair is still easy. 1/50000th of the hair is harder than x meters. Also, meters are fixed measurement, while hairs vary in size.
    • The width is usually on the order of tens of nanometers; length can be up to multiple centimeters.

      • by Eudial ( 590661 )

        I think that's tenths of micrometers, which is on the edge of what our eyes can resolve.

    • by Gertlex ( 722812 )

      Also, meters are fixed measurement, while hairs vary in size.

      The diameters of carbon nanotubes varies over an order of magnitude. So g'luck with that.

    • by Anonymous Coward

      Could we stop with this nonsense and go back to the old ways where we stated lengths in the terms relative to the length of the football fields?

      For those of you too lazy to do the math, football field is 109.7m, diameter of hair is 17-180 micrometres (I'll be using 60). So 1/50000th of a hair is about 1/9.14E10 football fields.

    • Imagine a hair's diameter is 50 km then the diameter of a nanotube is 1 meter. This gives you a pretty good idea how the dimensions compare ;)
    • You want to measure the width of a carbon nanotube in *meters*? How is that easier?

      Even if you meant to say nanometers, I disagree with your argument. A human hair is a measure of a daily object that people can intuitively grasp. The measurement, "one meter", however, is not an intuitive concept. You still need to relate it to something in order to grasp it, even if it's just holding out your hands to show how far it is.

  • by Foobar_ ( 120869 ) on Sunday December 19, 2010 @12:42AM (#34604884)

    Here's the Brown/KIST researchers' video, a rendered simulation showing the buckling action http://www.youtube.com/watch?v=PzNqW_d0QGc&fmt=18 [youtube.com]

    This is a mildly related movie of actual electron microscopy of a flat graphene sheet finding its most stable configuration after a hole was punched in it http://www.youtube.com/watch?v=EogdalfXF4c&feature=related&fmt=18 [youtube.com]

    The broken nanotube under high pressure has the advantage of having lots of other carbon atoms in a similar predicament close enough nearby that the tube's wall can reform, while the flat sheet simply falls apart due to its own tension and lattice vibrations.

    • Is it just me or is my brain 'feeling' some odd pattern from the breakdown in the first video, especially when compared to the other video?

      The model seems to match actual video by showing reformation and deformation of atomic links in rapid order.

      anyways, too late to think. Night!

  • by Gertlex ( 722812 ) on Sunday December 19, 2010 @01:30AM (#34605108)

    Carbon nanotubes (CNTs) and irradiation happen to be the general subject of a term project I'm finishing up...

    There's a lot of uses for CNTs ( http://www.sciencemag.org/content/297/5582/787.full [sciencemag.org] Might work. Might be paywalled. Yay University). The article didn't look to specific. (Or just plain wrong) I'm not clear if they're cutting a single CNT at a time or not.

    One approach I've seen is suspending CNTs in a H2O2 solution, and irradiating with gamma rays to get shorter more uniform lengths of CNTs. The result basically is sphaghetti. A potential application though is as an additive in epoxies for strength. Identify the ideal length for structural purposes, and irradiate CNTs to get said length. This article also mentioned using ultrasonic treatment or whatever to shorten CNTs. (So this article is not new science, I think) ("Shortening of multi-walled carbon nanotubes by c-irradiation in the presence of hydrogen peroxide," Jung, et al., 2008)

    I've also seen electron irradiation for cutting multi-walled nanotubes. The electron microscope pics look almost like chopped up tree trunks.

    Diameter of (single walled) CNTs is on the order of 0.5 to 5 nm. (Interestingly, carbon fiber fibers have diameters on the scale of microns, e.g. 1000x greater)

  • by 93 Escort Wagon ( 326346 ) on Sunday December 19, 2010 @01:35AM (#34605126)

    Hire a teeny tiny samurai.

  • Make emo nanotubes, they cut themselves! Bahaha, I'm pretty funny!
  • Only they are powerful and precise enough to cut something like that.

  • Brings new meaning to the phrase measure twice, cut once.

  • Human hair thickness varies by a factor of 10.

"No, no, I don't mind being called the smartest man in the world. I just wish it wasn't this one." -- Adrian Veidt/Ozymandias, WATCHMEN