Add another ‘nano’ contraction to the list: Nanoyarn. In this case, the ‘yarn’ is composed of nanotubes created from boron nitride. (Boron nitride is what makes ‘clown white’ white.) The word yarn is suggestive of possible uses and reasonably accurate. The new nanoyarn, manufactured for the first time by the U.S. Department of Energy Jefferson Lab, is composed of very long fibers (centimeters in length – very long for nanotechnology) that can be used like traditional yarn in weaving, cloth, cloth-like surfaces and so forth. The boron nitride nanotubes have a structure similar to carbon nanotubes, but have very different properties.
Carbon nanotubes and boron nitride nanotubes can both be rolled into sheets, but carbon nanotubes can be metallic or semiconducting (electrically active), boron nitride nanotubes are electrical insulators. They are also more stable under heat and chemical action. These properties will guide the many potential uses of boron nitride nanoyarn.
Researchers at NASA’s Langley Research Center, the Department of Energy’s Thomas Jefferson National Accelerator Facility and the National Institute of Aerospace created a new technique to synthesize high-quality boron-nitride nanotubes (BNNTs). They are highly crystalline and have a small diameter. They also structurally contain few walls and are very long. Boron nitride is the white material found in clown make-up and face powder.
“Before, labs could make really good nanotubes that are short or really crummy ones that are long. We’ve developed a technique that makes really good ones that are really long,” said Mike Smith, a staff scientist at NASA’s Langley Research Center.
The synthesis technique, called the pressurized vapor/condenser (PVC) method, was developed with Jefferson Lab’s Free-Electron Laser and later perfected using a commercial welding laser. In this technique, the laser beam strikes a target inside a chamber filled with nitrogen gas. The beam vaporizes the target, forming a plume of boron gas. A condenser, a cooled metal wire, is inserted into the boron plume. The condenser cools the boron vapor as it passes by, causing liquid boron droplets to form. These droplets combine with the nitrogen to self-assemble into BNNTs.
The researchers say the next step is to test the properties of the new boron-nitride nanotubes to determine the best potential uses for the new material. They are also attempting to improve and scale up the production process.
“Theory says these nanotubes have energy applications, medical applications and, obviously, aerospace applications.”
[Source: Jefferson Lab (U.S. DOE)]