Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Caltech Chemists Develop Simple Technique to Visualize Atomic-Scale Structures

Atomic force micrograph of a one-atom thick sheet of graphene trapping water on a mica surface. The ice crystals (lightest blue) are the height of a two-water-molecule thick ice crystal. This first layer of water is ice, even at room temperature. At high humidity levels, a second layer of water will coat the first layer, also as ice. At very high humidity levels, additional layers of water will coat the surface as droplets. [Credit: Heath group/Caltech]
Atomic force micrograph of a one-atom thick sheet of graphene trapping water on a mica surface. The ice crystals (lightest blue) are the height of a two-water-molecule thick ice crystal. This first layer of water is ice, even at room temperature. At high humidity levels, a second layer of water will coat the first layer, also as ice. At very high humidity levels, additional layers of water will coat the surface as droplets. [Credit: Heath group/Caltech]

Abstract:
Researchers at the California Institute of Technology (Caltech) have devised a new technique—using a sheet of carbon just one atom thick—to visualize the structure of molecules. The technique, which was used to obtain the first direct images of how water coats surfaces at room temperature, can also be used to image a potentially unlimited number of other molecules, including antibodies and other biomolecules.

By Kathy Svitil

Caltech Chemists Develop Simple Technique to Visualize Atomic-Scale Structures

Pasadena, CA | Posted on September 3rd, 2010

A paper describing the method and the studies of water layers appears in the September 3 issue of the journal Science.

"Almost all surfaces have a coating of water on them," says James Heath, the Elizabeth W. Gilloon Professor and professor of chemistry at Caltech, "and that water dominates interfacial properties"—properties that affect the wear and tear on that surface. While surface coatings of water are ubiquitous, they are also very tough to study, because the water molecules are "in constant flux, and don't sit still long enough to allow measurements," he says.

Quite by accident, Heath and his colleagues developed a technique to pin down the moving molecules, under room-temperature conditions. "It was a happy accident—one that we were smart enough to recognize the significance of," he says. "We were studying graphene on an atomically flat surface of mica and found some nanoscale island-shaped structures trapped between the graphene and the mica that we didn't expect to see."

Graphene, which is composed of a one-atom-thick layer of carbon atoms in a honeycomb-like lattice (like chicken wire, but on an atomic scale), should be completely flat when layered onto an atomically flat surface. Heath and his colleagues—former Caltech graduate student Ke Xu, now at Harvard University, and graduate student Peigen Cao—thought the anomalies might be water, captured and trapped under the graphene; water molecules, after all, are everywhere.

To test the idea, the researchers conducted other experiments in which they deposited the graphene sheets at varying humidity levels. The odd structures became more prevalent at higher humidity, and disappeared under completely dry conditions, leading the researchers to conclude that they indeed were water molecules blanketed by the graphene. Heath and his colleagues realized that the graphene sheet was "atomically conformal"—it hugged the water molecules so tightly, almost like shrink wrap, that it revealed their detailed atomic structure when examined with atomic force microscopy. (Atomic force microscopes use a mechanical probe to essentially "feel" the surfaces of objects.)

"The technique is dead simple—it's kind of remarkable that it works," Heath says. The method, he explains, "is sort of like how people sputter carbon or gold onto biological cells so they can image them. The carbon or gold fixes the cells. Here, the graphene perfectly templates the weakly adsorbed water molecules on the surface and holds them in place, for up to a couple of months at least."

Using the technique, the researchers revealed new details about how water coats surfaces. They found that the first layer of water on mica is actually two water molecules thick, and has the structure of ice. Once that layer is fully formed, a second, two-molecule-thick layer of ice forms. On top of that, "you get droplets," Heath says. "It's truly amazing that the first two adsorbed layers of water form ice-like microscopic islands at room temperature," says Xu. "These fascinating structures are likely important in determining the surface properties of solids, including, for example, lubrication, adhesion, and corrosion."

The researchers have since successfully tested other molecules on other types of atomically flat surfaces—such flatness is necessary so the molecules don't nestle into imperfections in the surface, distorting their structure as measured through the graphene layer. "We have yet to find a system for which this doesn't work," says Heath. He and his colleagues are now working to improve the resolution of the technique so that it could be used to image the atomic structure of biomolecules like antibodies and other proteins. "We have previously observed individual atoms in graphene using the scanning tunneling microscope," says Cao. "Similar resolution should also be attainable for graphene-covered molecules."

"We could drape graphene over biological molecules—including molecules in at least partially aqueous environments, because you can have water present—and potentially get their 3-D structure," Heath says. It may even be possible to determine the structure of complicated molecules, like protein-protein complexes, "that are very difficult to crystallize," he says.

Whereas the data from one molecule might reveal the gross structure, data from 10 will reveal finer features—and computationally assembling the data from 1,000 identical molecules might reveal every atomic nook and cranny.

If you imagine that graphene draped over a molecule is sort of like a sheet thrown over a sleeping cat on your bed, Heath explains, having one image of the sheet-covered lump—in one orientation—"will tell you that it's a small animal, not a shoe. With 10 images, you can tell it's a cat and not a rabbit. With many more images, you'll know if it's a fluffy cat—although you won't ever see the tabby stripes."

The work in the paper, "Graphene Visualizes the First Water Adlayers on Mica at Ambient Conditions," was funded by the United States Department of Energy's Office of Basic Energy Sciences.

####

For more information, please click here

Contacts:
Kathy Svitil

Copyright © Caltech

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

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

Traffic jam in empty space: New success for Konstanz physicists in studying the quantum vacuum January 22nd, 2017

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

Govt.-Legislation/Regulation/Funding/Policy

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

Traffic jam in empty space: New success for Konstanz physicists in studying the quantum vacuum January 22nd, 2017

A toolkit for transformable materials: How to design materials with reprogrammable shape and function January 20th, 2017

'5-D protein fingerprinting' could give insights into Alzheimer's, Parkinson's January 19th, 2017

Academic/Education

Oxford Nanoimaging report on how the Nanoimager, a desktop microscope delivering single molecule, super-resolution performance, is being applied at the MRC Centre for Molecular Bacteriology & Infection November 22nd, 2016

The University of Applied Sciences in Upper Austria uses Deben tensile stages as an integral part of their computed tomography research and testing facility October 18th, 2016

Enterprise In Space Partners with Sketchfab and 3D Hubs for NewSpace Education October 13th, 2016

New Agricultural Research Center Debuts at UCF October 12th, 2016

Nanotubes/Buckyballs/Fullerenes

Captured on video: DNA nanotubes build a bridge between 2 molecular posts: Research may lead to new lines of direct communication with cells January 9th, 2017

Nano-chimneys can cool circuits: Rice University scientists calculate tweaks to graphene would form phonon-friendly cones January 4th, 2017

WPI researchers build liquid biopsy chip that detects metastatic cancer cells in blood December 15th, 2016

Infrared instrumentation leader secures exclusive use of Vantablack coating December 5th, 2016

Announcements

The speed limit for intra-chip communications in microprocessors of the future January 23rd, 2017

New, old science combine to make faster medical test: Nanoparticles and Faraday rotation allow faster diagnoses January 23rd, 2017

Traffic jam in empty space: New success for Konstanz physicists in studying the quantum vacuum January 22nd, 2017

A big nano boost for solar cells: Kyoto University and Osaka Gas effort doubles current efficiencies January 21st, 2017

Tools

Chemists Cook up New Nanomaterial and Imaging Method: Nanomaterials can store all kinds of things, including energy, drugs and other cargo January 19th, 2017

Nanometrics to Announce Fourth Quarter and Full Year Financial Results on February 7, 2017 January 19th, 2017

Distinguishing truth under the surface: electrostatic or mechanic December 31st, 2016

Nanomechanics Inc. Continues Growth in Revenue and Market Penetration: Leading nanoindentation company reports continued growth in revenues and distribution channels on national and international scales December 27th, 2016

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