One of the latest additions
to the expanding menagerie of carbon nanostructures is the
single walled carbon nanotube (SWNT) that encapsulates a
string of spherical C60 molecules. Each C60 is only 0.7 nm
in diameter and appears as a circle in the high resolution
micrograph shown above.
This nanoscopic peapod was announced by its discoverers,
Brian Smith (Penn), David Luzzi (Penn) and Marc Monthioux
(CEMES, France), in Nature [396, 323 (1998)].
Utilizing the high resolution imaging and in-situ capabilities
of the TEMs in the facility, the encapsulated buckyballs
are seen to move back and forth inside the nanotubes, lining
up in groups of two, three, or more -- just like arrangements
of beads on an abacus.
This finding opens a new field in nanotube research and
could conceivably affect the interpretation of earlier results,
which were obtained with the supposition that the tubes are
empty. "Very, very cool -- just mind-blowing" commented
fullerene researcher Daniel Colbert (Rice). "I think
they probably will end up teaching us something about the
nucleation and growth of nanotubes."
excerpted in part from Chemical & Engineering News 77
(2), 32 (1999)