Featured Research

from universities, journals, and other organizations

New properties of graphene, world's thinnest material, discovered

Date:
June 15, 2010
Source:
Northwestern University
Summary:
Researchers have discovered that graphene oxide sheets behave like surfactants, the chemicals in soap and shampoo that make stains disperse in water.

Graphene oxide sheets stabilized organic solvent droplets in water.
Credit: Image courtesy of Northwestern University

Graphene oxide, a single-atomic-layered material made by reacting graphite powders with strong oxidizing agents, has attracted a lot of interest from scientists because of its ability to easily convert to graphene -- a hotly studied material that scientists believe could be used to produce low-cost carbon-based transparent and flexible electronics.

Related Articles


But to Jiaxing Huang, assistant professor of materials science and engineering, and his research group at the McCormick School of Engineering and Applied Science at Northwestern University, graphene oxide itself is even more interesting. Huang and his group have studied the material for years and have discovered how to assemble these soft sheets like floating water lilies pads. They also used a camera flash to turn them into graphene, and invented a fluorescence quenching technique to make them visible under microscopes.

Now, working with Kenneth R. Shull, professor of materials science and engineering, they have discovered that graphene oxide sheets behave like surfactants, the chemicals in soap and shampoo that make stains disperse in water. The team's results are published online in the Journal of the American Chemical Society.

Graphene oxide has been known in the scientific world for more than a century and was largely described as hydrophilic, or attracted to water. But Huang and his research group thought that graphene oxide should be amphiphilic, a property of surfactants that can both attracts and repels water, because part of the graphene oxide structure is actually water repelling.

"We view graphene oxide as a soft material," Huang says. "For example, it is essentially two-dimensional polymers composed of carbon, hydrogen and oxygen. They are also colloidal particles with very exotic shapes."

To test their hypothesis, Huang and his group put graphene oxide in carbonated water. They found that the sheets can hitchhike onto the rising bubbles to reach the water surface -- just like a surfactant would do. Next they found that graphite oxide can disperse oil droplets in water -- just like a surfactant would.

This new insight into a fundamental property of the material, according to Huang, is important for understanding how graphene oxide is processed and handled. It could lead to new applications for the material.

Its surfactant properties mean it could be used as a dispersing agent for insoluble materials, like carbon nanotubes. Common surfactants are non-conducting, so when used as a dispersing agent for conducting materials, they need to be removed from the material. Graphite oxide, which turns into conducting graphene through heating, would actually help conductivity.

The surfactant behavior inspired another exciting discovery -- that water surface can act as a filter for separating graphene oxide sheets by size.

"The smaller the sheet, the more water-liking it becomes, so eventually it will sink into water," Huang says. This effect makes it easier to harvest large sheets of graphene oxide, which are more useful for graphene device fabrication.

This work was funded by the National Science Foundation. In addition to Huang and Shull, the other authors of the paper include graduate students Jaemyung Kim, Laura Cote, Wa Yuan and postdoc Franklin Kim.


Story Source:

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


Journal Reference:

  1. Jaemyung Kim, Laura J. Cote, Franklin Kim, Wa Yuan, Kenneth R. Shull, Jiaxing Huang. Graphene Oxide Sheets at Interfaces. Journal of the American Chemical Society, 2010; 132 (23): 8180 DOI: 10.1021/ja102777p

Cite This Page:

Northwestern University. "New properties of graphene, world's thinnest material, discovered." ScienceDaily. ScienceDaily, 15 June 2010. <www.sciencedaily.com/releases/2010/06/100614132000.htm>.
Northwestern University. (2010, June 15). New properties of graphene, world's thinnest material, discovered. ScienceDaily. Retrieved January 30, 2015 from www.sciencedaily.com/releases/2010/06/100614132000.htm
Northwestern University. "New properties of graphene, world's thinnest material, discovered." ScienceDaily. www.sciencedaily.com/releases/2010/06/100614132000.htm (accessed January 30, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, January 30, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nanoscale Sensor Could Help Wine Producers and Clinical Scientists

Nanoscale Sensor Could Help Wine Producers and Clinical Scientists

Reuters - Innovations Video Online (Jan. 30, 2015) — A nanosensor that mimics the oral effects and sensations of drinking wine has been developed by Danish and Portuguese researchers. Jim Drury saw it in operation. Video provided by Reuters
Powered by NewsLook.com
Tesla 'Insane Mode' Gives Unsuspecting Passengers the Ride of Their Life

Tesla 'Insane Mode' Gives Unsuspecting Passengers the Ride of Their Life

RightThisMinute (Jan. 29, 2015) — If your car has an "Insane Mode" then you know it&apos;s fast. Well, these unsuspecting passengers were in for one insane ride when they hit the button. Tesla cars are awesome. Video provided by RightThisMinute
Powered by NewsLook.com
Now Bill Gates Is 'Concerned' About Artificial Intelligence

Now Bill Gates Is 'Concerned' About Artificial Intelligence

Newsy (Jan. 29, 2015) — Bill Gates joins the list of tech moguls scared of super-intelligent machines. He says more people should be concerned, but why? Video provided by Newsy
Powered by NewsLook.com
Senate Passes Bill for Keystone XL Pipeline

Senate Passes Bill for Keystone XL Pipeline

AP (Jan. 29, 2015) — The Republican-controlled Senate has passed a bipartisan bill approving construction of the Keystone XL oil pipeline. (Jan. 29) Video provided by AP
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:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

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