US Patent 8057777 - Controlling chirality of nanotubes

http://www.freepatentsonline.com/8057777.html

There have been many laboratory methods proposed to separate semiconducting from metallic carbon nanotubes after fabrication but most of these methods complicate industrial production of nanotubes. This method from Nanocomp Technology instead introduces an approach applied during manufacture where the chirality of the nanotubes which determines the semiconducting or metallic properties is controlled. Claim 1 reads:

1. A method for manufacturing nanotubes, the method comprising:

exposing a plurality of catalyst particles from which nanotubes can grow to a substantially high frequency field;

resonating the catalyst particles at a selected resonant frequency keyed to a radial breathing mode unique to a desired chiral nature of a nanotube to be manufactured; and

allowing those nanotubes having a resonant frequency substantially similar to the selected resonant frequency, and thus the unique desired chiral nature, to be grown.