Thursday, December 13, 2007

豆腐文摘:Exploration of SWNT Cloning Continues

Amplification of Single-Walled Carbon Nanotubes from Designed Seeds: Separation of Nucleation and Growth

Douglas Ogrin, Robin E. Anderson, Ramon Colorado, Jr., Benji Maruyama, Mark J. Pender, Valerie C. Moore, Sean T. Pheasant, Laura McJilton, Howard K. Schmidt, Robert H. Hauge, W. Edward Billups, James M. Tour, Richard E. Smalley, and Andrew R. Barron

J. Phys. Chem. C, 2007, 111 (48), 17804-17806 (an Article in R. E. Smalley Special Issue).
Abstract Full: HTML / PDF (308K) Supporting Info

Scientists at Rice and AFRL continued their exploration on Smalley's ingenius idea of SWNT "cloning". The idea was such that known chirality or type of SWNTs (sorted somehow) are cut into small pieces that are then attached with catalyst particles for further SWNT growth. This growth is supposed to follow the same chirality pattern of the original nanotube seed.

The scientists used FeMoC catalysts to couple to the pyridine-functionalized, shortened SWNT. After further growth, the results seem to suggest that around 3 times of length increase was achieved for short nanotubes (< 200 nm) with further growth (and perhaps the lack of growth of longer nanotubes also) limited by SWNT-SOG substrate interactions.

As a short paper, it lacks many details, although it might be deliberate. A reader may immediately raise questions such as the following:

(1) At the end of p.1, it is stated "Care was taken to ensure that any unreacted FeMoC is removed prior to characterization or growth". How?

(2) According to the AFM quality of Figure 1, it seems difficult to have a rather reliable nanotube length counting for "as-synthesized SWNT-cats" and thus the accuracy of the major claim (3 times length growth).

(3) Where are the radial breathing modes??

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