US Patent 7291318 - Transforming nanopeapods to double wall nanotubes

http://www.freepatentsonline.com/7291318.html

Some fullerene manufacturing processes produce peapod carbon structures with C60 (buckyballs) encapsulated within a single walled carbon nanotube. This patent from Toyota teaches a method to transform these "nanopeapods" into double walled carbon nanotubes. Claim 1 reads:

1. A method for manufacturing multi-wall carbon nanotubes comprising: a process for preparing fullerene/carbon nanotube hybrid structures wherein assembled fullerenes, these being fullerenes that are linked, are housed within carbon nanotubes, and a process whereby the hybrid structures are subjected to electron beam irradiation while in a heated state, thereby forming interior tubes from the assembled fullerenes; wherein the hybrid structures are subjected to irradiation with the electron beams while in a state of being heated to 80-700.degree.C.