Extralong Molecules
Carbon nanotubes stretch out

Context: Little more than a nanometer wide, carbon nanotubes have become superstars of the nano world: unusually strong, electrically conductive, and stable at high temperatures. Fibers composed of nanotubes should outperform those made from any existing material. However, the length of the tubes -- most are only tenths of a millimeter long -- requires that they be lined up for peak performance. Now, researchers at Los Alamos National Laboratory and Duke University have created nanotubes that are centimeters long, and whose length is checked only by the size of the chamber used to create them.

Methods and Results: The Los Alamos team synthesized the nanotubes by flowing ethanol vapors at 900 degreesC over an iron catalyst spotted onto a silicon wafer. Tubes grew from these catalyst spots; the catalyst was pushed along the wafer surface in the direction of the gas flow. The longest tubes grew to four centimeters as straight lines across the length of the silicon wafer, terminating only at the wafer's edge.