US Patent 7332222 - Carbon nanotube peapod

http://www.freepatentsonline.com/7332222.html

Filling the cavities (i.e. lumens) of SWNTs is used as a method to functionalize or dope nanotubes for specific applications. Metal is often used as such a dopant creating metallofullerenes but this patent focuses on an alternative using fullerene as interior material for the SWNTs creating a structure similar to a peapod (with fullerene buckyballs forming the "peas" and the SWNT forming the "pod"). Claim 1 reads:

1. A hybrid material comprising: a. a first single-walled nanotube having a lumen; and b. a plurality of regularly spaced fullerene molecules contained within the lumen of the first single-walled nanotube.

Interestingly, an earlier patent (US 6,473,351) which was applied by the examiner disclosed using similar carbon nanotube peapods for a data storage application. However, the applicant submitted a Rule 131 declaration swearing behind the priority date of US 6,473,351 (Feb. 12, 1999) and actually published a paper in 1998 disclosing the discovery (Smith et al. Encapsulated C-60 in Carbon Nanotubes, Nature, Vol.396, No.6709, 323-324, 1998).