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Nanotubes Not for Toothpaste . . . Yet

Researchers Squeeze Even Rock-Hard Materials Through Minuscule Carbon Tubes

Electrons hitting an iron-carbide filled carbon nanotube cause it to contract and extrude material.

Electrons hitting an iron carbide-filled carbon nanotube cause it to contract and extrude material.
Credit and Larger Version

July 25, 2006

When researchers fire electron beams at multi-layered carbon nanotubes, they collapse, much like a tube of toothpaste, with such force the nanotubes extrude whatever may be inside, even extremely hard iron carbide. The process--which has applications for manufacturing durable, metal nanowires and similar materials--creates pressures within the tubes that reach one-tenth the crushing force in the Earth's core.

National Science Foundation-supported researcher Pulickel Ajayan of Rensselaer Polytechnic Institute (RPI) worked with an international team to develop the process. First, the researchers constructed long nanotubes of onion-like layers of carbon containing a 9-nanometer (billionth of a meter) core of iron or iron carbide, and then they blasted the tube with a beam of electrons. The tube collapsed, extruding an iron-carbide wire only 2 nanometers in diameter. What's more, the tube neatly pinched off the wire's end where the tube collapsed completely.

The findings appeared in the May 26, 2006, issue of the journal Science.  Florian Banhart of Johannes Gutenberg University in Mainz, Germany, led the team, which included colleagues at the Institute for Scientific and Technological Research in San Luis Potosi, Mexico, and the University of Helsinki in Finland.

Additional information is available in the RPI press release linked below.

-- Josh Chamot

Pulickel Ajayan

Related Institutions/Organizations
Rensselaer Polytechnic Institute

Troy , New York

Related Awards
#0303174 Inter-American Materials Collaboration: Large Scale Synthesis of N-doped Carbon Nanotubes for the Fabrication of Novel Polymer Composites and Related Low Dimensional Materials

Total Grants

Related Websites
Carbon Nanomaterials Research Group: http://www.rpi.edu/~ajayan/locker/INDEX.HTM
RPI Press Release on Dr. Ajayan's work: http://news.rpi.edu/update.do?artcenterkey=1579

Electron micrographs reveal the atomic structure of the carbon nanotube and its filler material.
Electron micrographs reveal the atomic structure of the carbon nanotube and its filler material.
Credit and Larger Version

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