nanomachined carbon: nanotubes, fullerenes, peapods
David Tománek
Department
of Physics and Astronomy
Michigan State
University
East Lansing,
Michigan 48824-1116
http://www.pa.msu.edu/~tomanek/
517-355-9702(phone) 517-353-4500 (fax)
Abstract
In recent years, following the discovery of the C60 “buckyball”, a plethora of nanostructures attracted the attention of carbon scientists. Examples of these intriguing systems are other fullerenes, onions, nanotubes, and hybrid structures such as peapods. Whereas most of these sp2 bonded structures are known to grow from carbon vapor under extreme conditions, structures like multi-wall nanocapsules may form by activated bond rearrangement from ultra-disperse diamond [1] or highly defective graphitic structures.
I will show how macroscopic concepts from elasticity theory translate down to the nanometer scale, where they provide quantitative predictions for the relative stability of nanotubes, scrolls, fullerenes, and peapods. With the help of ab initio calculations, it is now possible to study the formation and inter-conversion mechanism of other carbon nanostructures. Molecular dynamics simulations (see http://www.pa.msu.edu/cmp/csc/ and the figure below) provide intriguing insights into the formation mechanism of peapods [2] and the unexpected structural stability of entangled nanotube “hooks”, reminiscent of the velcro bond.
[1] Young-Kyun Kwon, David Tománek, and Sumio Iijima, "Bucky-Shuttle" Memory Device: Synthetic Approach and Molecular Dynamics Simulations, Phys. Rev. Lett. 82, 1470 (1999).
[2] Savas Berber, Young-Kyun Kwon, and David Tománek, Nano-golf: Putting a C60 into a Nanotube (submitted for publication).
Figure: Visualization
of a possible end-on encapsulation process of a C60 fullerene in a
(10,10) carbon nanotube
(see also http://www.pa.msu.edu/cmp/csc/simulpeapod.html
).
Keywords: nanotubes, fullerenes, energy, formation