Navigation Links
Nanotechnologists reveal the frictional characteristics of atomically thin sheets
Date:4/1/2010

PHILADELPHIA - A team of nanotechnology researchers from the University of Pennsylvania and Columbia University has used friction force microscopy to determine the nanoscale frictional characteristics of four atomically-thin materials, discovering a universal characteristic for these very different materials. Friction across these thin sheets increases as the number of atomic layers decreases, all the way down to one layer of atoms. This friction increase was surprising as there previously was no theory to predict this behavior.

The finding reveals a significant principle for these materials, which are widely used as solid lubricant films in critical engineering applications and are leading contenders for future nanoscale electronics.

Researchers found that friction progressively increased as the number of layers is reduced on all four materials, regardless of how different the materials may behave chemically, electronically or in bulk quantities. These measurements, supported by computer modeling, suggest that the trend arises from the fact that the thinner a material the more flexible it is, just as a single sheet of paper is much easier to bend than a thick piece of cardboard.

Robert Carpick, professor in the Department of Mechanical Engineering and Applied Mechanics at Penn, and James Hone, professor in the Department of Mechanical Engineering at Columbia, led the project collaboratively.

The team tested the nanotribological, or nano-scale frictional properties, of graphene, molybdenum disulfide (MoS2), hexagonal-BN (h-BN) and niobium diselenide (NbSe2) down to single atomic sheets. The team literally shaved off atomic-scale amounts of each material onto a silicon oxide substrate and compared their findings to the bulk counterparts. Each material exhibited the same basic frictional behavior despite having electronic properties that vary from metallic to semiconducting to insulating.

"We call this mechanism, which leads to higher friction on thinner sheets the 'puckering effect,'" Carpick said. "Interatomic forces, like the van der Waals force, cause attraction between the atomic sheet and the nanoscale tip of the atomic force microscope which measures friction at the nanometer scale."

Because the sheet is so thin in some samples only an atom thick it deflects toward the tip, making a puckered shape and increasing the area of interaction between the tip and the sheet, which increases friction. When the tip starts to slide, the sheet deforms further as the deformed area is partially pulled along with the tip, rippling the front edge of the contact area. Thicker sheets cannot deflect as easily because they are much stiffer, so the increase in friction is less pronounced.

The researchers found that the increase in friction could be prevented if the atomic sheets were strongly bound to the substrate. If the materials were deposited onto the flat, high-energy surface of mica, a naturally occurring mineral, the effect goes away. Friction remains the same regardless of the number of layers because the sheets are strongly stuck down onto the mica, and no puckering can occur.

"Nanotechnology examines how materials behave differently as they shrink to the nanometer scale," Hone said. "On a fundamental level, it is exciting to find yet another property that fundamentally changes as a material gets smaller."

The results may also have practical implications for the design of nanomechanical devices that use graphene, which is one of the strongest materials known. It may also help researchers understand the macroscopic behavior of graphite, MoS2 and BN, which are used as common lubricants to reduce friction and wear in machines and devices.


'/>"/>

Contact: Jordan Reese
jreese@upenn.edu
215-573-6604
University of Pennsylvania
Source:Eurekalert  

Related biology technology :

1. Nanotechnologists gain powerful new materials probe
2. Nanotechnologists from Penn collaborate to form near-frictionless diamond material
3. New Survey Reveals Many Adults With High Cholesterol Fail to Take Necessary Steps to Improve Their Condition
4. Actelion Announces Multiple Presentations on Tracleer(R) and the REVEAL Registry at CHEST 2007
5. New Data Reveal Ethnicity May Play Role in Weight Loss Decisions
6. New paper reveals nanoscale details of photolithography process
7. Stem Cell Agency Finally Reveals Institutions Involved in Conflict Problem
8. Experiments reveal unexpected activity of fuel cell catalysts
9. Biochip mimics the body to reveal toxicity of industrial compounds
10. Survey of More than 600 Patients Treated with Tracleer(R) (bosentan) Reveals Actelion Sure Steps(R) Patient Support Program Provides Valuable Educational Information
11. Developing Sales Leaders: Benchmarks Reveal Tactics that Will Propel Your Business
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Nanotechnologists reveal the frictional characteristics of atomically thin sheets
(Date:10/10/2017)... ... October 10, 2017 , ... For the ... won a US2020 STEM Mentoring Award. Representatives of the FirstHand program travelled to ... Experience from US2020. , US2020’s mission is to change the trajectory of STEM ...
(Date:10/10/2017)... ... October 10, 2017 , ... USDM Life Sciences , ... life sciences and healthcare industries, announces a presentation by Subbu Viswanathan and Jennifer ... “Automating GxP Validation for Agile Cloud Platforms,” will present a revolutionary approach to ...
(Date:10/9/2017)... (PRWEB) , ... October 09, 2017 , ... At its ... Dr. Christopher Stubbs, a professor in Harvard University’s Departments of Physics and Astronomy, has ... was a member of the winning team for the 2015 Breakthrough Prize in Fundamental ...
(Date:10/7/2017)... , ... October 06, 2017 ... ... in Hi-C-based genomic technologies, launched its ProxiMeta™ Hi-C metagenome deconvolution product, featuring ... kit and accompanying cloud-based bioinformatics software to perform Hi-C metagenome deconvolution using ...
Breaking Biology Technology:
(Date:4/17/2017)... 17, 2017 NXT-ID, Inc. (NASDAQ: NXTD ... filing of its 2016 Annual Report on Form 10-K on Thursday ... ... available in the Investor Relations section of the Company,s website at ... website at http://www.sec.gov . 2016 Year Highlights: ...
(Date:4/11/2017)... No two people are believed to ... York University Tandon School of Engineering and Michigan ... partial similarities between prints are common enough that ... and other electronic devices can be more vulnerable ... in the fact that fingerprint-based authentication systems feature ...
(Date:4/5/2017)... , April 4, 2017 KEY FINDINGS ... anticipated to expand at a CAGR of 25.76% during ... diseases is the primary factor for the growth of ... report: https://www.reportbuyer.com/product/4807905/ MARKET INSIGHTS The global ... product, technology, application, and geography. The stem cell market ...
Breaking Biology News(10 mins):