Patent ID: 7727505

Claim:
A method for separating carbon nanotubes, comprising, in sequence: providing a mixture of carbon nanotubes; introducing an aryldiazonium salt having an end group capable of being chelated by a metal ion to the mixture of carbon nanotubes to covalently bond the aryldiazonium salt to a surface of at least one of the carbon nanotubes wherein the end group capable of being chelated is selected from the group consisting of hydroxamic acid, phosphonic acid, dipyridine, terpyridine, phthalocyanine, and mixtures thereof; introducing a metal salt to the mixture of carbon nanotubes to chelate the end group of the aryldiazonium salt with the metal ion of the metal salt; and centrifuging the mixture of carbon nanotubes to cause the separation of the carbon nanotubes based on a density differential of the carbon nanotubes.