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University of Surrey Electronic Engineers’ Revolutionary Discovery

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28.10.2002

A University of Surrey team led by Professor Ravi Silva has demonstrated a new method of growing carbon nanofibres at room temperature. Published in this week’s Nature Materials, the technique they have used involves substituting the thermal energy requirements for growth with plasma decomposition of methane on the Ni catalyst.

Professor Silva said “We believe that vapour-grown carbon fibres would offer the most cost-effective means of producing discontinuous carbon fibres using large-scale catalytic processes. This can now be realised at a much lower temperature than previously thought and to our knowledge this is the first demonstration of the growth of carbon nanofibres at room temperatures, by any method.”

To date methods which have been developed have involved discharge, and vaporisation using laser, pyrolysis and chemical vapour deposition of hydrocarbons at very high temperatures. The lower growth temperature allows for the removal of the silicon dioxide barrier layer associated with catalytic growth, and should allow in-situ growth of nanofibres on relatively large areas of temperature sensitive substrates, such as plastics, organics or even paper. This discovery could make many applications possible, such as large-area flat-panel displays and electrochemical cells, and could even be compatible with biomolecular electronics. Carbon nanofibres synthesised by this method are also potential candidates for polymer composite fabrication and nanoelectronics.

Carbon nanotubes were first identified by S Iijima in an article published in Nature in 1991. They are extremely long and thin structures found in carbon as regular and symmetrical as crystals which is a result of the elongation of the C60 fullerene molecule which is composed of 60 carbon atoms. Following in the footsteps of 1996 Nobel Prize winners Curl, Kroto and Smalley who discovered the unique structure of carbon atoms bound in the form of a ball, Ravi and his collaborators have studied the structure and properties of the tiny tubes, which are approximately 10,000th of the diameter of a human hair. The atoms arrange themselves in hexagonal rings like chicken wire, which adds to their strength and it is this bonding property of carbon which makes diamonds so hard. Ravi and his team have developed novel ways of depositing multi-walled carbon nanofibres that form into nano-ropes during the growth process and are producing structures that are now large enough not only to be picked up and held in the hand, by tweezers of course, but single structures that are also visible to the naked eye.

Liezel Tipper | Source: alphagalileo
Further information: www.nature.com

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