It has been suggested previously that single-walled carbon nanotubes (SWCNTs) would be cut in tension, or by high-temperature chemical reactions in the ultrasonication manufacture processes. Kyung-Suk Kim and co-workers, Brown University, USA, and the Korea Institute of Science and Technology, have shown that this is not the case.
By using molecular dynamics simulations, they have shown that the tubes are compressed at either end by sonic booms, causing them to buckle in 5 nm sections called the compression-concentration zone. In that zone, the tube is twisted into alternating 90° folds, so it resembles a helix. The tubes are cut through the force exerted by sonic booms, which causes atoms to be ejected from the tube’s lattice.
The group also found that cutting SWCNT by sonication creates multiple kinks along the tubes’ length. The kinks are “highly attractive intramolecular junctions for building molecular-scale electronics,” the researchers write.
- Compressive dynamic scission of carbon nanotubes under sonication: fracture by atomic ejection
H. B. Chew, M.-W. Moon, K. R. Lee, K.-S. Kim,
Proc. R. Soc. A 2010.
- Video of molecular simulations of nanotube fracturing can be found here >>>