Nanotubes take on the Grand Canyon

Science News, April 17, 2004

Imagine reducing one of the most awe-inspiring geologic formations on Earth to the size of a dust particle. Although that may not have been Ravindra Kane's goal, he and his colleagues at Rensselaer Polytechnic Institute in Troy, N.Y., recently fabricated Grand Canyon-like structures out of carbon nanotubes.

These configurations arose in work targeted at making new materials with specific functions. First, the materials scientists vertically aligned arrays of carbon nanotubes on a glass surface, creating the effect of a densely wooded forest. The researchers next exposed the nanotubes to a plasma that oxidized them. Finally, the team dunked the oxidized nanotubes in a water solution. As the liquid evaporated, the nanotube forest began to bend, crack, and reorganize itself into a stable network of miniaturized canyons.

By altering the height of the nanotubes or by modifying the initial pattern of the vertically aligned tubes, the researchers could control the ultimate orientation and shape of the microlandscape.

For instance, in a separate experiment, Kane and his team created a carbon-nanotube forest featuring an array of circular gaps. When the researchers provided the liquid-evaporation treatment to this arrangement, the nanotubes collapsed into a layer of foam punctuated by regularly shaped square and octagonal cells. Because these nanotube foams are lightweight, pliable, and elastic, Kane says, they could be ideal as sound dampeners or shock absorbers.--A.G.