US Patent 7641883 - Viologen CNT separation

http://www.freepatentsonline.com/7641883.html

This patent from Samsung teaches a new carbon nanotube processing method using viologen to separate semiconducting from metallic nanotubes. Claim 1 reads:

1. A method for separating carbon nanotubes into metallic carbon nanotubes and semiconducting carbon nanotubes, comprising:

forming a solution comprising viologen, carbon nanotubes, water and a non-polar solvent;

performing a phase separation on the solution comprising viologen, carbon nanotubes, water and a non-polar solvent, wherein the water and the non-polar solvent are phase-separated from the solution of carbon nanotubes, viologen, water and non-polar solvent, thereby separating the carbon nanotubes into metallic carbon nanotubes and semiconducting carbon nanotubes.