Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Molecular depth profiling modeled with buckyballs and argon

The rectangular depression is the result of multiple bombardments of the surface with buckyballs and argon during a depth-profiling procedure. Image: Zbigniew Postawa, Jagiellonian University, Poland
The rectangular depression is the result of multiple bombardments of the surface with buckyballs and argon during a depth-profiling procedure. Image: Zbigniew Postawa, Jagiellonian University, Poland

Abstract:
A team of scientists led by a Penn State University chemist has demonstrated the strengths and weaknesses of an alternative method of molecular depth profiling—a technique used to analyze the surface of ultra-thin materials such as human tissue, nanoparticles, and other substances. In the new study, the researchers used computer simulations and modeling to show the effectiveness and limitations of the alternative method, which is being used by a research group in Taiwan. The new computer-simulation findings may help future researchers to choose when to use the new method of analyzing how and where particular molecules are distributed throughout the surface layers of ultra-thin materials.

Molecular depth profiling modeled with buckyballs and argon

Philadelphia, PA | Posted on October 11th, 2011

Team leader Barbara Garrison, the Shapiro Professor of Chemistry and the head of the Department of Chemistry at Penn State University, explained that bombarding a material with buckyballs—hollow molecules composed of 60 carbon atoms that are formed into a spherical shape resembling a soccer ball—is an effective means of molecular depth profiling. The name, "buckyball," is an homage to an early twentieth-century American engineer, Buckminster Fuller, whose design of a geodesic dome very closely resembles the soccer-ball-shaped 60-carbon molecule.

"Researchers figured out a few years ago that buckyballs could be used to profile molecular-scale depths very effectively," Garrison explained. "Buckyballs are much bigger and chunkier than the spacing between the molecules at the surface of the material being studied, so when the buckyballs hit the surface, they tend to break it up in a way that allows us to peer inside the solid and to actually see which molecules are arranged where. We can see, for example, that one layer is composed of one kind of molecule and the next layer is composed of another kind of molecule, similar to the way a meteor creates a crater that exposes sub-surface layers of rock."

Garrison and her colleagues decided to use computer modeling to test the effectiveness of an alternative approach that another research group had been using. The other group had used not only large, high-energy buckyballs to bombard a surface, but also another smaller, low-energy chemical element—argon—in the process. "In our computer simulations, we modeled the bombardment of surfaces first with high-energy buckyballs and then later, with low-energy argon atoms," Garrison said.

Garrison's group found that, with buckyball bombardment alone at grazing angles, the end result is a very rough surface with many troughs and ridges in one direction.

"In many instances, this approach works out well for depth profiling. However, in other instances, using buckyballs alone makes for a bumpy surface on which to perform molecular depth profiling because the molecules can be distributed unevenly throughout the peaks and valleys," Garrison explained. "In these instances, when low-energy argon bombardment is added to the process, the result is a much more even, smoother surface, which, in turn, makes for a better area on which to do analyses of molecular arrangement. In these cases, researchers can get a clearer picture of the many layers of molecules and exactly which molecules make up each layer."

However, Garrison's team also concluded that the argon must be low enough in energy in order to avoid further damage of the molecules that are being profiled.

"According to our simulations, the bottom line is that the buckyball conditions that the other research group used are not the best for depth profiling; thus, co-bombardment with low-energy argon assisted the process," Garrison said. "That is, the co-bombardment method works only in some very specific instances. We do not think low-energy argon will help in instances where the buckyballs are at sufficiently high energies." Garrison added that previous researchers had tried using smaller, simpler atomic projectiles at high, rather than low energies, but these projectiles tended to simply penetrate deeply into the surface, without giving scientists a clear view into the arrangement and identity of the molecules beneath.

Garrison said that molecular depth profiling is a crucial aspect of many chemical experiments and its applications are far-reaching. For example, molecular depth profiling is one way to get around the challenges of working with something so small and intricate as a biological cell. A cell is composed of thin layers of distinct materials, but it is difficult to slice into something so tiny to analyze the composition of those super-fine layers. In addition, molecular depth profiling can be used to analyze other kinds of human tissue, such as brain tissue—a process that could help researchers to understand neurological disease and injury. In the future, molecular depth profiling also could be used to study nanoparticles—extremely small objects with dimensions of between 1 and 10 nanometers, visible only with an electron microscope. Because nanoparticles already are being used experimentally as drug-delivery systems, a detailed analysis of their properties using molecular depth profiling could help researchers to test the effectiveness of the drug-delivery systems.

In addition to Garrison, other members of the research team include Zachary J. Schiffer, a high-school student at the State College Area High School near the Penn State University Park campus, Paul E. Kennedy of Penn State's Department of Chemistry, and Zbigniew Postawa of the Smoluchowski Institute of Physics at Jagiellonian University in Poland.

####

For more information, please click here

Copyright © Penn State 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 Links

Molecular Dynamics Simulations Elucidate the Synergy of C60 and Low-Energy Ar Cobombardment for Molecular Depth Profiling

Related News Press

News and information

Strength in numbers: Researchers develop the first-ever quantum device that detects and corrects its own errors March 4th, 2015

New research could lead to more efficient electrical energy storage March 4th, 2015

Energy-generating cloth could replace batteries in wearable devices March 4th, 2015

Arrowhead to Present at 2015 Barclays Global Healthcare Conference March 4th, 2015

Nanotubes/Buckyballs

Researchers turn unzipped nanotubes into possible alternative for platinum: Aerogel catalyst shows promise for fuel cells March 2nd, 2015

Chromium-Centered Cycloparaphenylene Rings as New Tools for Making Functionalized Nanocarbons February 24th, 2015

Building tailor-made DNA nanotubes step by step: New, block-by-block assembly method could pave way for applications in opto-electronics, drug delivery February 23rd, 2015

Half spheres for molecular circuits: Corannulene shows promising electronic properties February 17th, 2015

Discoveries

Energy-generating cloth could replace batteries in wearable devices March 4th, 2015

Experiment and theory unite at last in debate over microbial nanowires: New model and experiments settle debate over metallic-like conductivity of microbial nanowires in bacterium March 4th, 2015

Magnetic vortices in nanodisks reveal information: Researchers from Dresden and Jülich use microwaves to read out information from smallest storage devices March 4th, 2015

CiQUS researchers obtain high-quality perovskites over large areas by a chemical method March 4th, 2015

Announcements

Experiment and theory unite at last in debate over microbial nanowires: New model and experiments settle debate over metallic-like conductivity of microbial nanowires in bacterium March 4th, 2015

Magnetic vortices in nanodisks reveal information: Researchers from Dresden and Jülich use microwaves to read out information from smallest storage devices March 4th, 2015

CiQUS researchers obtain high-quality perovskites over large areas by a chemical method March 4th, 2015

Arrowhead to Present at 2015 Barclays Global Healthcare Conference March 4th, 2015

Research partnerships

New research could lead to more efficient electrical energy storage March 4th, 2015

Cambrios and Heraeus Jointly Create New, High-Conductivity Transparent Conductors: Two Companies' Combined Products Dramatically Extend Flexible Substrate Capabilities for Next-Generation Mass-Market Technology Products March 3rd, 2015

The taming of magnetic vortices: Unified theory for skyrmion-materials March 3rd, 2015

UC research partnership explores how to best harness solar power March 2nd, 2015

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