Due to carbon’s wide applications, it is not surprising that it is also a key component in the rising field of nanotechnology. Beside its natural occurrence in the form of graphite and diamond, carbon exists in the nanostructured forms of fullerenes or buckyballs and in carbon nanotubes. The beauty of carbon nanotubes formed by carbon atoms is that they are twofold stronger than steel but weigh six times less.
Carbon nanotubes are allotropes of carbon that have been first constructed by S. Iijima in 1991. These are significantly extended thin cylinders and large macromolecules of carbon with unique features in their shape, size and physical properties as well as having the highest ratio up to 28,000,000 between length and diameter (Zheng, 2004). This is larger than any other material in the world. They can be envisioned by taking a mass of graphite into consideration that is rolled into a cylinder shown as Appendix-I figure (i) on page 6. These fascinating structures have flashed world wide great excitement and appraisal during last few years. Currently a huge amount of money is being spent on these carbon nanotubes to improve the understanding of their properties. Still its physical characteristics are being discovered and controversial results are being obtained. The development and research on synthesis methods is considered as a vital step to the future outlook of carbon nanotechnology.
The structure of a carbon nanotube can be envisioned by taking a mass of graphite into consideration that is rolled into a cylinder as shown in figure (i) on page 6. Nanotubes, on the basis of the direction of hexagons, are classified as zigzag, armchair or chiral and are shown as Appendix-I figure (ii) on page 6. There are two types of carbon nanotube i.e. single-walled nanotubes (SWNT) and multi-walled nanotubes (MWNT). Generally SWNT are composed of a diameter close to1 nanometer while the tube length that can have a length millions of times longer and are excellent