US Patent 7785472 - Structure-selective separation of CNTs

http://ip.com/patent/US7785472

This patent from Japan Science and Technology Agency teaches a way to take advantage of the correlation between the structure-sensitive electronic energy level of a carbon nanotube and the redox potential of a metal to sort nanotubes based on diameter and chirality. Claim 1 reads:

1. A method of separating, concentrating, or refining a carbon nanotube having a desired physical property from a sample solution, wherein the desired physical property includes at least one of a diameter or a chiral vector, the method comprising:

a) irradiating light to the sample solution containing carbon nanotubes in the presence of metal ions, so that the metal ions are respectively reduced and deposited on the carbon nanotubes, and

b) selecting the carbon nanotubes having the desired physical property by applying a predetermined magnetic field or chromatography to the carbon nanotubes so as to precipitate the carbon nanotubes with the desired physical property.