Featured Research

from universities, journals, and other organizations

Pulling polymers leads to new insights into their mechanical behavior

Date:
March 4, 2014
Source:
Universität Basel
Summary:
Scientists have pulled up isolated molecular chains from a gold surface, using the tip of an atomic force microscope (AFM). The observed signal provides insight into the detachment force and binding energy of molecules. Atomic force microscopy is a method normally used for imaging matter with very high resolution. The sharp tip of the microscope is used to scan the surface line by line. The resolution is so high, that single atoms can be seen.

The tip of an AFM pulling off a molecular chain vertically from a gold surface.
Credit: Illustration: Shigeki Kawai

In collaboration with colleagues from Berlin and Madrid, researchers at the Department of Physics at the University of Basel have pulled up isolated molecular chains from a gold surface, using the tip of an atomic force microscope (AFM). The observed signal provides insight into the detachment force and binding energy of molecules. The results have been published in the renowned scientific journal PNAS.

Atomic force microscopy is a method normally used for imaging matter with very high resolution. The sharp tip of the microscope is used to scan the surface line by line. The resolution is so high, that single atoms can be seen. "This method is roughly equivalent to using the tip of the Matterhorn to scan the surface of a tennis ball," says Prof. Ernst Meyer of the Department for Physics at the University of Basel. Due to an improved method, the scientists are now able to investigate the mechanical behavior of a single polymer being pulled off a surface.

Using the tip of the AFM, the researchers were able to pull single chains of molecules (polymers) off a gold surface. "The molecule-surface interaction during pulling is so weak that each chain link (molecular unit) detaches successively. Thus, the whole chain can be pulled off almost vertically to the surface," explains Meyer. By analyzing the observed oscillations, the researchers are able to make quantitative statements on the binding energy of each molecular unit.

Motion without friction

Furthermore, the experiments showed that the polymers could be pulled off with almost no lateral forces. This remarkable behavior of nearly frictionless motion was predicted by a theoretical model and has now been verified for molecules on a gold surface. Previously, the mechanical behavior of single polymer during pulling from a surface had never been investigated with atomic-scale resolution. The findings and calculations of the research team now provide detailed insight into this process for the first time.

Such investigations are not only of interest for the field of physics, but also for biology and chemistry, since the method of pulling polymers from surfaces can also be applied to biological molecules. So far, valuable insights have been obtianed into the folding and unfolding of DNA and proteins. Chemical reactions of small biopolymer sub units or complex polymer chains under the influence of traction forces and catalytic nanoparticles could be investigated with this new method.


Story Source:

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


Journal Reference:

  1. S. Kawai, M. Koch, E. Gnecco, A. Sadeghi, R. Pawlak, T. Glatzel, J. Schwarz, S. Goedecker, S. Hecht, A. Baratoff, L. Grill, E. Meyer. Quantifying the atomic-level mechanics of single long physisorbed molecular chains. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1319938111

Cite This Page:

Universität Basel. "Pulling polymers leads to new insights into their mechanical behavior." ScienceDaily. ScienceDaily, 4 March 2014. <www.sciencedaily.com/releases/2014/03/140304071206.htm>.
Universität Basel. (2014, March 4). Pulling polymers leads to new insights into their mechanical behavior. ScienceDaily. Retrieved August 28, 2014 from www.sciencedaily.com/releases/2014/03/140304071206.htm
Universität Basel. "Pulling polymers leads to new insights into their mechanical behavior." ScienceDaily. www.sciencedaily.com/releases/2014/03/140304071206.htm (accessed August 28, 2014).

Share This




More Matter & Energy News

Thursday, August 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) — Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) — Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) — Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) — An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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:
from the past week

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