Joined: 16 Mar 2004
|Posted: Thu Dec 07, 2006 11:20 am Post subject: Materials scientists tame tricky carbon nanotubes
|Based on a new theory, MIT scientists may be able to manipulate carbon nanotubes - one of the strongest known materials and one of the trickiest to work with - without destroying their extraordinary electrical properties.
The work is reported in the Sept. 15 issue of Physical Review Letters.
Carbon Nanotubes - cylindrical carbon molecules 50,000 times thinner than a human hair - have properties that make them potentially useful in nanotechnology, electronics, optics and reinforcing composite materials. With an internal bonding structure rivaling that of another well-known form of carbon, diamonds, carbon nanotubes are extraordinarily strong and can be highly efficient electrical conductors.
The problem is working with them. There is no reliable way to arrange the tubes into a circuit, partly because growing them can result in a randomly oriented mess resembling a bowl of spaghetti.
Researchers have attached to the side walls of the tiny tubes chemical molecules that work as "handles" that allow the tubes to be assembled and manipulated. But these molecular bonds also change the tubes' structure and destroy their conductivity.
Now Young-Su Lee, an MIT graduate student in materials science and engineering, and Nicola Marzari, an associate professor in the same department, have identified a class of chemical molecules that preserve the metallic properties of carbon nanotubes and their near-perfect ability to conduct electricity with little resistance.
Using these molecules as handles, Marzari and Lee said, could overcome fabrication problems and lend the nanotubes new properties for a host of potential applications as detectors, sensors or components in novel optoelectronics.
This story was posted on 19th September 2006.