Featured Research

from universities, journals, and other organizations

Rice University's Chemical 'Scissors' Yield Short Carbon Nanotubes; New Process Yields Nanotubes Small Enough To Migrate Through Cells

Date:
July 23, 2003
Source:
Rice University
Summary:
Chemists at Rice University have identified a chemical process for cutting carbon nanotubes into short segments. The new process yields nanotubes that are suitable for a variety of applications, including biomedical sensors small enough to migrate through cells without triggering immune reactions.

HOUSTON-- July 22, 2003 -- Chemists at Rice University have identified a chemical process for cutting carbon nanotubes into short segments. The new process yields nanotubes that are suitable for a variety of applications, including biomedical sensors small enough to migrate through cells without triggering immune reactions.

The chemical cutting process involves fluorinating the nanotubes, essentially attaching thousands of fluorine atoms to their sides, and then heating the fluoronanotubes to about 1,000 Celsius in an argon atmosphere. During the heating, the fluorine is driven off and the nanotubes are cut into segments ranging in length from 20-300 nanometers.

"We have studied several forms of chemical 'scissors,' including other fluorination methods and processes that involve ozonization of nanotubes," said John Margrave, the E.D. Butcher Professor of Chemistry at Rice University. "With most methods, we see a random distribution among the lengths of the cut tubes, but pyrolytic fluorination results in a more predictable distribution of lengths."

By varying the ratio of fluorine to carbon, Margrave and recent doctoral graduate Zhenning Gu can increase or decrease the proportion of cut nanotubes of particular lengths. For example, some fluorine ratios result in nearly 40 percent of cut nanotubes that are 20 nanometers in length. That's smaller than many large proteins in the bloodstream, so tubes of that length could find uses as biomedical sensors. By varying the process, Margrave hopes to maximize the production of lengths of nanotubes that are useful in molecular electronics, polymer composites, catalysis and other applications.

Carbon nanotubes are a type of fullerene, a form of carbon that is distinct from graphite and diamond. When created, they contain an array of carbon atoms in a long, hollow cylinder that measures approximately one nanometer in diameter and several thousand nanometers in length. A nanometer is one billionth of a meter, or about 100,000 times smaller than a human hair.

Since discovering them more than a decade ago, scientists have been exploring possible uses for carbon nanotubes, which exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond, and as much as 100 times the strength of steel at one-sixth the weight. In order to capitalize on these properties, researchers and engineers need a set of tools -- in this case, chemical processes like pyrolytic fluorination -- that will allow them to cut, sort, dissolve and otherwise manipulate nanotubes.

Margrave said his team is already at work finding a method to sort the cut tubes by size. One technique they are studying is chromatography, a complex form of filtering. Margrave hopes to re-fluorinate the cut tubes, mix them with a solvent and pour the mixture through a column of fine powder that will trap the shorter nanotubes. Another sorting method under study is electrophoresis, which involves the application of an electric field to a solution.

Margrave's group is researching other ways that fluorination can be used to manipulate carbon nanotubes, which are chemically stable in their pure form. The highly-reactive fluorine atoms, which are attached to the walls of the nanotubes, allow scientists to create subsequent chemical reactions, attaching other substances to the nanotube walls. In this way, the group has created dozens of "designer" nanotubes, each with its own unique properties.


Story Source:

The above story is based on materials provided by Rice University. Note: Materials may be edited for content and length.


Cite This Page:

Rice University. "Rice University's Chemical 'Scissors' Yield Short Carbon Nanotubes; New Process Yields Nanotubes Small Enough To Migrate Through Cells." ScienceDaily. ScienceDaily, 23 July 2003. <www.sciencedaily.com/releases/2003/07/030723083644.htm>.
Rice University. (2003, July 23). Rice University's Chemical 'Scissors' Yield Short Carbon Nanotubes; New Process Yields Nanotubes Small Enough To Migrate Through Cells. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2003/07/030723083644.htm
Rice University. "Rice University's Chemical 'Scissors' Yield Short Carbon Nanotubes; New Process Yields Nanotubes Small Enough To Migrate Through Cells." ScienceDaily. www.sciencedaily.com/releases/2003/07/030723083644.htm (accessed September 19, 2014).

Share This



More Matter & Energy News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com
Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins