A simple method for the containment and purification of filled open-ended single wall carbon nanotubes using C60 molecules.

Soluble materials placed inside opened SWNTs can be contained using fullerenes to block the ends, thereby providing a way to remove the excess of external soluble material present in the initial product formed by low temperature filling of open-ended single wall carbon nanotubes; the C60-blocked filled SWNTs can then be used in applications in which leakage is undesirable.