Press releases
Please quote Nature Materials as the source of these items.
September 2004
Length without limit
When nanotubes were first discovered, in the early 1990s, researchers envisaged applications such as continuous thin ropes for a 'space elevator' that would link the earth to objects in space. But such applications, which would exploit the unparalleled strength and stiffness of nanotubes, require the growth of ultra-long nanotubes that can be woven into macroscopic fibres. In the October issue of Nature Materials, Yuntian Zhu and colleagues report the growth of single-walled carbon nanotubes with no intrinsic length limit.
Zhu and colleagues use vapour deposition in combination with a metal catalyst to grow the ultra-long nanotubes at a high growth rate of 11 micrometres per second. The researchers found that if the nanotubes could be kept free-floating above the substrate, they grew in a straight line without any defects. Growth was only terminated when the catalyst particle on the tip of the nanotube came into contact with the substrate and caused the nanotube to develop a kink.
The longest nanotube grown by Zhu et al. was four centimetres, with a weight of the order of 0.1 picograms. Although large-scale synthesis of much longer nanotubes would be necessary to weave nanofibres for use in a space elevator, other applications are more immediate — such as the use of long metallic nanotubes as interconnects in electronic circuits.
Ultralong single-wall carbon nanotubes pp673-676
L. X. Zheng, M. J. O'Connell, S. K. Doorn, X. Z. Liao, Y. H. Zhao, E. A. Akhadov, M. A. Hoffbauer, B. J. Roop, Q. X. Jia, R. C. Dye, D. E. Peterson, S. M. Huang, J. Liu and Y. T. Zhu
Published online: 12 September 2004 | doi 10.1038/nmat1216
