Nanotube web could mimic brain

Researchers from NASA Ames Research Center have found a way to grow minuscule webs of connected carbon nanotubes.

These networks could herald a new type of electronics that have huge numbers of random connections, a setup similar to a brain's synapses. Such networks could also form sensors, parts for conventional electronics, or templates for assembling materials molecule-by-molecule.

Nanotubes, which are rolled-up sheets of carbon atoms that appear naturally in soot, are central to many nanotechnology projects.

To provide a place for nanotubes to grow and connect, the researchers collapsed microscopic spheres of polystyrene suffused with a catalyst. The microspheres were 500 to 2,000 nanometers across and several to several hundred nanometers apart. The researchers burned away the polystyrene, leaving smaller spheres of the catalyst.

The researchers were able to control the number of nanotubes and connections that grew on each sphere by varying the solution mix and microsphere size. Nanotubes can be a small as one nanometer, or the width of 10 hydrogen atoms.

The structures could be used as sensors in two to five years, and in electronics in 10 to 20 years, according to the researchers. The work apeared in the February 3, 2003 issue of Applied Physics Letters.