US Patent 7387735 - Acidic solution for isolating semiconductor CNTs

http://www.freepatentsonline.com/7387735.html

This patent from Samsung teaches a new method for isolating semiconducting single walled carbon nanotubes using a mixture of nitric and sulfuric acids. Claim 1 reads:

1. A method of isolating semiconducting carbon nanotubes, comprising:

mixing carbon nanotubes with a mixed acid solution of nitric acid and sulfuric acid to obtain a carbon nanotube dispersion; stirring the carbon nanotube dispersion at room temperature; and

filtering the carbon nanotube dispersion; wherein a volume ratio of nitric acid: sulfuric acid in the mixed acid solution is in the range of about 1:9 to about 2:8.