Thursday, October 08, 2009

US Patent 7597869 - Length enhancement during CNT growth

In order to take advantage of the mechanical, optical, and electrical properties of carbon nanotubes it is useful to have longer nanotubes which can be woven into fibers. This patent from Hon Hai Precision Industry provides a solution to increase the lengths of carbon nanotubes produced by CVD methods. Claim 1 reads:

1. A method for producing carbon nanotubes, comprising the steps of:

providing a reaction chamber defining a reacting region therein;

providing a substrate having a catalyst layer formed thereon;

disposing the substrate in the reaction chamber;

introducing a carbon-containing reactive gas into the reaction chamber so as to grow carbon nanotubes using a chemical vapor deposition method; and

moving the substrate along a direction opposite to a growth direction of the carbon nanotubes whilst growing the carbon nanotubes, wherein tips of the carbon nanotubes remain in the reacting region while the substrate is moving.