From NanoWerk: Rice scientists argue nanotubes can be treated like polymers
Wade Adams, Matteo Pasquali, Micah Green and Natnael Behabtu at Rice pick up that thread in their discussion of what we know — or think we know — about carbon nanotubes.
Their review in the journal Polymer (“Nanotubes as polymers”) makes the argument that single-walled carbon nanotubes (SWNTs) are polymers and should be treated as such.
The point is to remind the nano community that decades of research into polymers can be applied to their work and hasten the development of novel materials for all kinds of uses.
“In one of his earliest lectures about nanotubes, (late Rice professor and Nobel laureate) Rick Smalley said they’re the ultimate polymer molecule, with every atom in its place, just like a polymer chain would have,” said Adams, director of the Richard E. Smalley Institute for Nanoscale Science and Technology, who focused on polymers for many years at the Air Force Research Laboratory. “I really didn’t believe him initially.”
Adams said the goal is to change the mindset of a generation of scientists who have come to think of carbon nanotubes as special when, in a very important way, they’re not special at all.
“We were seeing a lot of literature out there about nanocomposites that were totally ignorant of the 15-, 20- and 30-year-old literature that explored a lot of these areas and had already clarified some of the things you need to think about if you’re going to use these materials,” he said.
The article coincides with an announcement of a new development in nanotube processing that does, in fact, treat nanotubes as polymers and thus allows for considerably greater industrial use:
Rice University scientists today unveiled a method for the industrial-scale processing of pure carbon-nanotube fibers that could lead to revolutionary advances in materials science, power distribution and nanoelectronics. The result of a nine-year program, the method builds upon tried-and-true processes that chemical firms have used for decades to produce plastics. The research is available online in the journal Nature Nanotechnology.
“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.”
This is something of a halfway-point to true industrial-scale nanotube use, though, since nanotubes still can’t be made with purity of the types that have the kinds of properties (e.g. conductivity) one would like:
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.