Why Sound Affects Nanotubes DiscoveredCategory: Science & Technology
Posted: July 12, 2012 06:06AM
Carbon nanotubes, like other carbon allotropes, have a great deal of potential in future technologies. In part this is because of their great strength, despite being very small. Working with them however is not easy because they can clump together and do not always grow to the same length. It was discovered some time ago that exposing the nanotubes to ultrasonic vibrations in a liquid can actually break apart the clumps, stretch shorter nanotubes, and break longer ones. Now researchers at Rice University have figured out how this happens.
In an interesting twist of science, two quite different theories for how nanotubes react when sonicated have been proven experimentally. This intrigued one of the Rice researchers and prompted the current work which has shown that indeed both theories are correct, just not all of the time.
The ultrasonic vibrations create bubbles in the liquid and these bubbles affect the nanotubes. If the nanotubes are short, the bubbles attach to the end of the nanotube, so as the bubble collapses, the tube is stretched. If the nanotubes are long however, the bubbles will attach to them in the middle, and when they collapse, the force breaks the nanotube in half.
This finding was not completely expected but is definitely welcome as it explains why both theories were experimentally verified. No doubt this information will be used in the future as nanotubes are incorporated into technologies such as batteries, biomedicine, power cables, and more.