In two new papers, Rice University researchers report using ultracentrifugation (UCF) to create highly purified samples of carbon nanotube species.
One team, led by Rice Professor Junichiro Kono and graduate students Erik Haroz and William Rice, has made a small but significant step toward the dream of an efficient nationwide electrical grid that depends on highly conductive quantum nanowire.
The other, led by Rice Professor Bruce Weisman and graduate student Saunab Ghosh, employed UCF to prepare structurally sorted batches of semiconducting nanotubes that could find critical uses in medicine and electronics.
UCF is what it sounds like: a super-fast version of the centrifuge process medical lab technicians use to separate blood cells from plasma.
The process involves suspending mixtures of single-walled carbon nanotubes in combinations of liquids of different densities. When spun by a centrifuge at up to 250,000 g that's 250,000 times the force of gravity the nanotubes migrate to the liquids that match their own particular densities. After several hours in the centrifuge, the test tube becomes a colorful parfait with layers of purified nanotubes. Each species has its own electronic and optical characteristics, all of which are useful in various ways.
Weisman's lab reported its results in today's online edition of Nature Nanotechnology. Weisman is a professor of chemistry at Rice.
Kono's lab reported its results recently in the online edition of ACS Nano. Kono is a professor in electrical and computer engineering and professor of physics and astronomy.
The lack of pure batches of nanotubes species "has been a real hindrance in the field for nearly 20 years," Weisman said. While the UCF technique is not new, Ghosh found careful fine-tuning of the gradient structure let him sort at least 10 of the numerous species of nanotubes contained in a single sample produced by the Rice-created Hi
|Contact: David Ruth|