Refined Formula for Carbon Nanotube Growth

Rice University theoretical physicist Boris Yakobson, acting upon sudden inspiration at a recent meeting, obtained a couple spare coffee cups from a server and a pair of scissors and proceeded to lay out an idea that could have far-reaching implications for the nanotechnology industry. Yakobson had come up with the seed of a simple formula that describes why nanotubes have chirality. Chirality is the property that describes the angle of the carbon atom hexagons that make up a nanotube's walls. The new knowledge may ultimately allow chemists to control the chirality of entire batches of nanotubes as the tubes are grown. Certain types of carbon nanotubes, called armchair nanotubes - so-called for the way their edges line up - have excellent conductivity and may be the key to lossless power transmission cables. Turn the hexagons 30 degrees and the nanotubes become what are called zigzag type, a semiconducting variant that has great value for electronic applications. Zigzags, armchairs, and all the nanotubes in between are defined by their chirality. Their electronic, chemical, and optical properties change with every degree between zero and 30 that the hexagons are tilted.

Transcript

00:00:00 [Music] I had idea to Illustrated with this coffee cup so I just borrowed from the lady who was in charge of coffees took scissors and they cut a few cups and placed them and did this demo and actually they like it because it's easy to understand carbon is one of amazing elements in the periodic table and as uh

00:00:31 as many of us know uh it assembles in variety of materials very important ones like diamond or graphite or discovered ferin and uh one of important variety which is still subject of active research is carbon nanot tubes and one of the big challenges in nanot tube uh synthesis and N production have been for two decades that they always emerge in a mix as a mixture all kinds

00:01:05 of helicities qualities mixed up and therefore very hard to separate them and very hard to Target specific application where you need only one type and from Theory standpoint it was really a puzzle why do they grow kyal and you see this shaking and vibrating this is thermal Motion in the bottom this slab is a catalyst particle this is metal it can be nickel or can be iron it can be

00:01:34 Cobalt what is important is this interface and as you see interface has this uh tight contact around but also area where contact is not very tight and that's exactly this uh inviting kind of spot and right now you saw that uh new carbon dimer just jumped in uh in this connection we we are quite excited the Insight that we obtained is not just satisfying but it also uh

00:02:07 hopefully will lead to engineering of a catalyst for variety of specific targets and variety of applications that it may become possible to to produce particular types of the tubes with a given properties separately from others in the labs and eventually in industrial seting [Music]