capped at their ends by pentagons ebbeson t w et al u201c large scale synthesis of carbon nanotubes u201d nature vol 358 220 221 1992 in order to allow for better filling the capped swnts can be opened in one embodiment by exposing the swnts to a reactive gas according to the present invention the introduction of the foreign material into the swnts can be accomplished either simultaneously with formation of the swnt or after the opening of the capped end or ends of the swnt in another embodiment sufficient heat may be applied to the capped swnt so as to open ends of the swnt kiang c h et al u201c structural modification of single layer carbon nanotubes with an electron beam u201d j phys chem vol 100 3749 3752 1996 in still another embodiment the capped end of the swnt may be exposed to a reactive liquid a strong acid such as hcl or hno 3 or a strong base such as ammonia in order to open the swnt in the following examples high resolution transmission electron microscopy hrtem studies were carried out on the synthesized samples the studies were done on phillips cm200 and cm300 microscopes equipped with gatan slow scan camera and image filter the cobalt catalyzed preparation of carbon nanotubes by arc discharge is described in u s pat no 5 424 054 the description thereof being incorporated herein by reference in this example bismuth was vaporized along with cobalt and graphite powder via the arc discharge method the addition of bismuth as a co catalyst and as a source for filling swnts presents a unique method and results in a.