Featured Research

from universities, journals, and other organizations

Polymeric Chains In "Flatland" Reveal Surprises, Researchers Say

Date:
August 9, 2000
Source:
University Of Illinois At Urbana-Champaign
Summary:
Contrary to what scientists have long thought, recent experiments at the University of Illinois have revealed that flexible polymers stuck to a solid surface crawl around in a very different way than they would in the bulk. This is important because the properties of polymers at surfaces play a central role in issues as wide-ranging as adhesives, coatings and biomedical implants.

CHAMPAIGN, Ill. - Contrary to what scientists have long thought, recent experiments at the University of Illinois have revealed that flexible polymers stuck to a solid surface crawl around in a very different way than they would in the bulk. This is important because the properties of polymers at surfaces play a central role in issues as wide-ranging as adhesives, coatings and biomedical implants.

Related Articles


"A polymer in 'Flatland' may sound like science fiction, but every bulk phase is connected to adjoining ones through its surface," said Steve Granick, a professor of materials science at the UI. Flatland refers to the title of an 1880 novel by Edwin Abbott that takes place essentially on a flat surface. "By examining the characteristics of individual polymeric chains, we can better predict the behavior and performance of bulk polymers."

As reported in the July 13 issue of the journal Nature, Granick and his UI colleagues -- biophysicist Enrico Gratton, materials scientist Kenneth Schweizer and postdoctoral research associates Svetlana Sukhishvili, Yan Chen and Joachim Muller -- exposed a specially prepared solid surface to a dilute solution of polyethylene glycol chains of varying length. Then they used an extremely sensitive measurement technique called two-photon fluorescence correlation spectroscopy, developed by biophysicists but never applied previously to materials science problems, to monitor the motions of individual molecules.

"Conventional theory said that a molecule twice as long would move half as fast," Granick said. "But our study shows a stronger dependence on chain length. Now the theorists must resharpen their pencils and make sense of observations that don't agree with their preconceptions."

When a molecular chain moves on a surface, it can't just go in any direction at random, Granick said. There is a preferred motion that lies in the direction the chain is pointed. This restrained motion is known to occur in bulk flexible polymers, but only when the chains are very long and tangled together like noodles of spaghetti. "Because the noodles interfere with one another, you can only pull one out along a preferred direction," Granick said. "But in Flatland, nearby chains are not needed to see this effect.

"This may mean that an individual molecule 'entangles' in some way with the solid surface. The many points at which the chain sticks to the surface may play a role analogous to the points of entanglement that occur when many chains are present."

In their experiments, the researchers also found that each thread-like chain of polyethylene glycol attached to the surface weakly along its entire length, causing it to flatten like a pancake.

"The molecule moves because individual parts of the pancake -- different links in the chain -- are wandering around, hopping on and off the surface," Granick said. "When there is slack between sticking points -- for example, in the loops of a flexible polymer -- the chain might propagate along its length in a caterpillar-like fashion."


Story Source:

The above story is based on materials provided by University Of Illinois At Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University Of Illinois At Urbana-Champaign. "Polymeric Chains In "Flatland" Reveal Surprises, Researchers Say." ScienceDaily. ScienceDaily, 9 August 2000. <www.sciencedaily.com/releases/2000/08/000807071245.htm>.
University Of Illinois At Urbana-Champaign. (2000, August 9). Polymeric Chains In "Flatland" Reveal Surprises, Researchers Say. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2000/08/000807071245.htm
University Of Illinois At Urbana-Champaign. "Polymeric Chains In "Flatland" Reveal Surprises, Researchers Say." ScienceDaily. www.sciencedaily.com/releases/2000/08/000807071245.htm (accessed October 25, 2014).

Share This



More Matter & Energy News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
Real-Life Transformer Robot Walks, Then Folds Into a Car

Real-Life Transformer Robot Walks, Then Folds Into a Car

Buzz60 (Oct. 24, 2014) Brave Robotics and Asratec teamed with original Transformers toy company Tomy to create a functional 5-foot-tall humanoid robot that can march and fold itself into a 3-foot-long sports car. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Police Testing New Gunfire Tracking Technology

Police Testing New Gunfire Tracking Technology

AP (Oct. 24, 2014) A California-based startup has designed new law enforcement technology that aims to automatically alert dispatch when an officer's gun is unholstered and fired. Two law enforcement agencies are currently testing the technology. (Oct. 24) Video provided by AP
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:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

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