Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Water lilies inspire scientists to create large-scale graphene films

Abstract:
In the world of nanomaterials, scientists and engineers can create new structures with tiny building blocks as small as one billionth of a meter.

But in order to construct new materials and devices, researchers first need to understand how these tiny units interact with each other.

Water lilies inspire scientists to create large-scale graphene films

Chicago, IL | Posted on January 29th, 2009

One such building block is graphite oxide, which is often used to make graphene — a hotly studied material that scientists believe could be used to produce low-cost carbon-based transparent and flexible electronics. Like graphene, graphite oxide is essentially a sheet that is only one atom thick, but can be as wide as tens of micrometers.

Jiaxing Huang, assistant professor of materials science and engineering at Northwestern University, and his research group at the McCormick School of Engineering and Applied Science set out to investigate how these graphite-oxide sheets assemble. Their results, published as the cover article in the Jan. 26 issue of the Journal of the American Chemical Society, surprised them.

"We were very curious how these extremely thin two-dimensional sheets interact with each other," Huang says. "This knowledge can also help to prepare better graphene thin films."

Huang and his group studied the sheets by putting them onto a water surface — a process called Langmuir-Blodgett assembly, which makes the sheets stay flat and allows scientists to move them around.

The effect reminded the researchers of water lilies on a pond, and Huang asked his sister to help to create a Chinese water painting similar to that of Claude Monet's series of paintings "Water Lilies" to demonstrate the idea. The artwork was chosen as one of the first illustrated covers for the 130-year-old journal.

Researchers used a barrier to push the sheets together to see how they would interact and then "fished" the interacting sheets off the water surface using glass slides or silicon wafers. Huang and his colleagues expected to see that individual sheets had stacked one upon the other, like a shuffled deck of cards. Instead they found that the edges of the graphite oxide sheets rumpled as they were pushed together.

"This was quite a surprise for us," Huang says. "Now we understand that electrostatic repulsion is the dominant interaction when these sheets are pushed together in this edge-to-edge geometry. This prevents graphite oxide layers from overlapping with each other."

When squeezed even further, the sheets eventually formed an interlocking structure that becomes a continuous membrane.

This film — consisting of flat, non-overlapping single layers tiling over large areas — has been very difficult to achieve by conventional thin-film processing techniques such as drop casting or spraying.

This breakthrough could have two immediate technological impacts. "Because we can keep them close to each other and still keep them flat, it provides high coverage of the surface with the single layers — which in turn will translate into high successful yield in graphene device fabrication," Huang says. "On the other hand, the continuous graphite oxide monolayer can be made into a transparent conductor after conversion to graphene."

Now, after studying how they interact edge-to-edge, Huang hopes to study face-to-face contact of the graphene-based materials. Stacking graphene sheets directly on top of each other will form graphite and lose the advantages of the single-atom-thick graphene materials. But Huang hopes to find a way to stack graphene without making graphite, which could create functional materials for energy-related applications such as electrodes for batteries, ultracapacitors and fuel cells.

"If we are good at making these tiny building blocks and if we can control how they assemble, we will create a lot of wonderful new things," Huang says.

In addition to Huang, co-authors of the paper include National Science Foundation graduate research fellow Laura Cote and postdoctoral fellow Franklin Kim, both of whom, according to Huang, "did a wonderful job" to create the high-quality graphite oxide sheets used in the experiment.

####

For more information, please click here

Contacts:
Kyle Delaney

847-467-4010

Copyright © Northwestern University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Advantest to Exhibit at SEMICON Korea in Seoul, South Korea February 4-6 Showcasing Broad Portfolio of Semiconductor Products, Technologies and Solutions January 29th, 2015

Park Systems Announces Innovations in Bio Cell Analysis with the Launch of Park NX-Bio, the only 3-in-1 Imaging Nanoscale Tool Available for Life Science Researchers January 29th, 2015

2015 Nanonics Image Contest January 29th, 2015

Iranian Scientists Use MOFs to Eliminate Dye Pollutants January 29th, 2015

Discoveries

Creating new materials with quantum effects for electronics January 29th, 2015

Los Alamos Develops New Technique for Growing High-Efficiency Perovskite Solar Cells: Researchers’ crystal-production insights resolve manufacturing difficulty January 29th, 2015

Iranian Scientists Use MOFs to Eliminate Dye Pollutants January 29th, 2015

Made-in-Singapore rapid test kit detects dengue antibodies from saliva: IBN's MedTech innovation simplifies diagnosis of infectious diseases January 29th, 2015

Announcements

Advantest to Exhibit at SEMICON Korea in Seoul, South Korea February 4-6 Showcasing Broad Portfolio of Semiconductor Products, Technologies and Solutions January 29th, 2015

Park Systems Announces Innovations in Bio Cell Analysis with the Launch of Park NX-Bio, the only 3-in-1 Imaging Nanoscale Tool Available for Life Science Researchers January 29th, 2015

2015 Nanonics Image Contest January 29th, 2015

Iranian Scientists Use MOFs to Eliminate Dye Pollutants January 29th, 2015

Energy

Los Alamos Develops New Technique for Growing High-Efficiency Perovskite Solar Cells: Researchers’ crystal-production insights resolve manufacturing difficulty January 29th, 2015

Carbon nanoballs can greatly contribute to sustainable energy supply January 27th, 2015

Visualizing interacting electrons in a molecule: Scientists at Aalto University and the University of Zurich have succeeded in directly imaging how electrons interact within a single molecule January 26th, 2015

Iranian Researchers Boost Solar Cells Efficiency Using Anti-Aggregates January 26th, 2015

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Nexeon Board Changes Announced January 29th, 2015

'Bulletproof' battery: Kevlar membrane for safer, thinner lithium rechargeables January 28th, 2015

Toyocolor to Launch New Carbon Nanotube Materials at nano tech 2015 January 24th, 2015

Smart keyboard cleans and powers itself -- and can tell who you are January 21st, 2015

Fuel Cells

New concept of fuel cell for efficiency and environment: It grasps both performance efficiency and removal of toxic heavy metal ions in direct methanol fuel cells January 5th, 2015

Toward a low-cost 'artificial leaf' that produces clean hydrogen fuel December 3rd, 2014

Single-atom gold catalysts may offer path to low-cost production of fuel and chemicals November 28th, 2014

National Synchrotron Light Source II Achieves 'First Light' October 23rd, 2014

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE