HELICITY AND PACKING OF SINGLE-WALLED CARBON NANOTUBES STUDIED BY ELECTRON NANODIFFRACTION

Electron nanodiffraction patterns from raft-like bundles of single-wal led carbon nanotubes have been obtained to analyze the helicity distri bution and the packing of the tubules. In most cases, the helical angl es were found to be quite evenly distributed, ranging from the zigzag structure of 0 degrees helicity to the armchair structure of 30 degree s helicity. Examples of preferred helicities were encountered occasion ally, such as bundles of tubules of almost single-helicity, correspond ing to the armchair structure. The lattice constant of the hexagonally packed bundles varied and two example values were determined to be 1. 64 nm and 1.71 nm, respectively.