Carbon Nanotube Multi-walled 60-100nm(diam.), 1-2micro m(length) / Multi-walled Carbon Nanotube
Carbon Nanotubes (CNT), which were discovered by Iijima in 1991, are composed entirely of carbon atoms, as is C60.1) As the name implies, this carbon structure is shaped like a tube on a nanometer scale. In 1991, Hufman and Kraetschmer reported a procedure for the preparation of C60 by an arc discharge. Many researchers had used this technique to obtain C60 from the soot which had collected on the anode. However, Iijima focused his attention on the soot which had accumulated on the cathode carbon rod. In this soot, Iijima found a needle like substance which he characterized as CNT. These early nanotubes were multi-walled carbon nanotubes (MWCNT), composed of many layers. Two years later, single-walled carbon nanotubes (SWCNT) were discovered. In 1996, Smalleys developed a mass production method of SWCNT2) and since then, research of CNT has progressed rapidly.
Today, researchers are making advances in the applications of CNT as probes for Scanning Probe Microscopy, nano-tweezers3), field-emitter of Field Emission Display (FED)4), nanoelectronics devices5), hydrogen fuel cells,6) thin films,7) and organic solar cells.8) Moreover, CNT generally tend to form bundles due to their van der Waals interactions, which makes them insoluble in organic solvents. In response to that, solvent-soluble CNT obtained by chemical modification have been developed and applied in many fields.9)