Navigation Links
Spin control: New technique sorts nanotubes by length
Date:5/16/2008

Researchers at the National Institute of Standards and Technology (NIST) have reported* a new technique to sort batches of carbon nanotubes by length using high-speed centrifuges. Many potential applications for carbon nanotubes depend on the lengths of these microscopic cylinders, and one of the most important features of the new technique, say the scientists, is that it should be easily scalable to produce industrial quantities of high-quality nanotubes.

So-called single wall carbon nanotubes (SWCNTs) are essentially sheets of carbon atoms only one atom thick that have rolled themselves into tubes with a diameter of approximately one nanometer. They have unique combinations of thermal, mechanical, optical and electronic properties that suggest a wide variety of uses, including circuit elements in molecular electronics, fluorescent tags for diagnostic and therapeutic applications in medicine and light sources for compact, efficient flat-panel displays, among many others.

Unfortunately, the methods for manufacturing carbon nanotubes always create a large percentage of nanojunk in the mixclumps of carbon, ordinary soot, particles of metal used as a catalystand nanotubes come in an enormous range of lengths, from a few tens or hundreds, up to thousands of nanometers. Refining the lot is essential for most uses. For many potential applications, nanotubes need to be separated by length. In biomedical applications, for example, it has been shown that whether or not nanotubes are taken up in cells depends critically on length (see Study: Cells Selectively Absorb Short Nanotubes.) Nanotubes used as components in future microcircuits obviously need to fit in place, and in optical applications, a nanotubes length determines how strongly it will absorb or emit light (see Longer is Better for Nanotube Optical Properties.)

In 2006, researchers found that you could separate nanotubes by chirality (a measure of the twist in the carbon atom sheet) by spinning them in a dense fluid in an ultracentrifuge tube because of a relationship between chirality and buoyancy. In this new work, a team of NIST researchers demonstrated that a variation of the same technique can separate nanotubes by length. They showed that while the nanotubes ultimately will move to a point of equilibrium in the centrifuge tube dictated by their buoyancy, due to friction they will move at different rates depending on their lengths.

When we spin the centrifuge, it turns out that the longer ones move faster. We basically just run a race and the longer ones move farther in the same amount of time, says researcher Jeffrey Fagan, Eventually they get separated enough in position that we can just pull off layers and get different lengths.

Whats particularly exciting, they say, is that while other techniques have been shown to sort nanotubes by length, this is the first approach that could be scaled up to produce commercially important quantities of nanotubes in a given length range. The process also removes much of unwanted junkparticularly metal particlesfrom the batch. NIST has applied for a patent on the process.


'/>"/>

Contact: Michael Baum
michael.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology news :

1. Development of new techniques to understand marble quality and durability
2. New technique determines the number of fat cells remains constant in all body types
3. Nature paper describes technique for extracting hierarchical structure of networks
4. New technique yields more detailed picture of chromatin structure
5. Argonne scientists develop techniques for creating molecular movies
6. Technique traces origins of disease genes in mixed human populations
7. New mineralogical techniques contribute to prevent national heritage damage
8. Powerful yet reliable proteomics techniques are the focus of a new methods book
9. Gene discovery made easier with powerful new networking technique
10. Fine print: New technique allows fast printing of microscopic electronics
11. New radar satellite technique sheds light on ocean current dynamics
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Spin control: New technique sorts nanotubes by length
(Date:4/15/2016)... , April 15, 2016  A new partnership ... more accurate underwriting decisions in a fraction of ... competitively priced and high-value life insurance policies to ... With Force Diagnostics, rapid testing (A1C, ... data readings (blood pressure, weight, pulse, BMI, and ...
(Date:4/13/2016)... CHICAGO , April 13, 2016  IMPOWER physicians ... are setting a new clinical standard in telehealth ... By leveraging the higi platform, IMPOWER patients can ... weight, pulse and body mass index, and, when they ... quick and convenient visit to a local retail location ...
(Date:3/29/2016)... , March 29, 2016 ... "Company") LegacyXChange "LEGX" and SelectaDNA/CSI Protect are pleased to ... ink used in a variety of writing instruments, ensuring ... of originally created collectibles from athletes on LegacyXChange will ... analysis of the DNA. Bill Bollander ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... ... June 24, 2016 , ... Researchers at the Universita ... miRNAs in people with peritoneal or pleural mesothelioma. Their findings are the subject of ... now. , Diagnostic biomarkers are signposts in the blood, lung fluid or tissue ...
(Date:6/23/2016)... 23, 2016   Boston Biomedical , an ... designed to target cancer stemness pathways, announced that ... Orphan Drug Designation from the U.S. Food and ... cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin is ... inhibit cancer stemness pathways by targeting STAT3, and ...
(Date:6/23/2016)... 23, 2016 Houston Methodist Willowbrook Hospital ... Sports Association to serve as their official health ... Methodist Willowbrook will provide sponsorship support, athletic training ... association coaches, volunteers, athletes and families. ... Sports Association and to bring Houston Methodist quality ...
(Date:6/23/2016)... -- The Biodesign Challenge (BDC), a university competition that asks ... systems and biotechnology, announced its winning teams at the ... York City . The teams, chosen ... MoMA,s Celeste Bartos Theater during the daylong summit. Keynote ... of architecture and design, and Suzanne Lee , ...
Breaking Biology Technology: