US Patent 7481989 - Equal length nanotube separation

http://www.freepatentsonline.com/7481989.html

This patent based on original research from Richard Smalley's group at Rice University (priority 1997) includes some basic claims to forming uniform length segments of nanotube material. Claim 1 reads:

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

(a) providing a fullerene nanotube-containing material;

(b) cutting the fullerene nanotube containing-material to form a mixture of fullerene nanotubes having lengths in the range of about 5 to 500 nm; and

(c) fractionating said mixture of fullerene nanotubes to form a fraction of said fullerene nanotubes having substantially equal lengths.