US Patent 7244408 - MWCNT distribution by arc discharge

http://www.freepatentsonline.com/7244408.html

Carbon nanotubes used in composites often have lengths exceeding 1 micron. This patent is focused on methods of making shorter nanotubes of a particular diameter distribution using the arc discharge method. Although, I'm not exactly certain why this would be useful (the application cites "more suitable for certain applications" without going into specifics). Claim 1 reads:

1. Nanotubes comprising of short multi-walled nanotubes (sh-MWNTs) formed from concentrically arranged nanotube layers having a mean outer diameter of from 2 to 15 nm, a median outer diameter of 6 to 8 nm and a natural length of 100 to 500 nm.