Opening and purification of carbon nanotubes in high yields

Gram‐quantities of pure carbon nanotubes (see Figure) can be produced using a new method reported here. The nanotubes, which can be thought of as cylindrical graphitic microcrystals, are opened and purified by treating them with a mixtue of sulfuric acid and potassium permanganate. The opening of the nanotubes on a large scale is also of interest in terms of filling the tubes with interesting guest molecules. (Figure Presented.)