Carbon nanotubes are the lab stars of nanotechnology. They can conduct electricity better than copper. They can behave like a metal – or a semiconductor. They can be 10 times stronger than steel. They can be controlled by heat or by magnetism. As coated tubes, they can contain medicine. In short, they’re extremely versatile, which means they have the potential for almost limitless applications. Except…they’re not easy to manufacture in quantity and not easy to process into commercially usable forms. Tackling the latter problem, a nine year research program conducted by Rice University (Texas, USA) and other institutions has led to methods for dissolving nanotubes and processing them like polymer (plastic) fluids.
“Plastics is a $300 billion U.S. industry because of the massive throughput that’s possible with fluid processing,” said Rice’s Matteo Pasquali, a paper co-author and professor in chemical and biomolecular engineering and in chemistry. “The reason grocery stores use plastic bags instead of paper and the reason polyester shirts are cheaper than cotton is that polymers can be melted or dissolved and processed as fluids by the train-car load. Processing nanotubes as fluids opens up all of the fluid-processing technology that has been developed for polymers.”
“The current research shows that we have a true solvent for nanotubes — chlorosulfonic acid — which is what we set out to find when we started this project nine years ago.”
But a final breakthrough remains before the true potential of high-quality carbon nanotubes can be realized. That’s because HiPco and all other methods of making high-end, “single-walled” nanotubes generate a hodgepodge of nanotubes with different diameters, lengths and molecular structures. Scientists worldwide are scrambling to find a process that will generate just one kind of nanotube in bulk, like the best-conducting metallic varieties, for instance.
“One good thing about the process that we have right now is that if anybody could give us one gram of pure metallic nanotubes, we could give them one gram of fiber within a few days,” Pasquali said.
[Source: Nanotechnology Today]