Featured Research

from universities, journals, and other organizations

Under Pressure At The Nanoscale, Polymers Play By Different Rules

Date:
October 13, 2008
Source:
University of Illinois at Urbana-Champaign
Summary:
Scientists putting the squeeze on thin films of polystyrene have discovered that at very short length scales the polymer doesn't play by the rules.

William P. King, a Kritzer Faculty Scholar and professor of mechanical engineering at Illinois, has discovered that at very short length scales the polymer doesn’t play by the rules.
Credit: Photo by L. Brian Stauffer

Scientists putting the squeeze on thin films of polystyrene have discovered that at very short length scales the polymer doesn't play by the rules.

From buttons to storage bins, the molding of polymers is big business. At the nanoscale, processes such as nanoimprint lithography squeeze polymers to form patterns during the manufacture of semiconductor devices, organic electronics and optics. Thin films of polymer are important in adhesives, coatings and lubricants.

"Although applications for nanoscale polymer flow are being widely investigated, the underlying, fundamental polymer physics is not," said William P. King, a Kritzer Faculty Scholar and professor of mechanical engineering at the University of Illinois.

"Understanding the way a polymer flows during nanoscale molding or imprinting processes is essential for designing new, nanoscale manufacturing processes," said King, who also is a researcher at the university's Beckman Institute.

In a paper to be published Thursday (Oct. 2), by Science Express, the online version of the journal Science, King and collaborators at the U. of I. and Trinity College, Dublin, report polymer squeeze flow measurements made at unprecedented, short length scales.

"We found an unexpected increase in the squeeze flow of thin films when the film thickness was smaller than 100 nanometers," King said. "This seemed backwards. Normally, you would expect the polymer to become harder and harder to press into thinner films."

The effect was even more pronounced in polymers of higher molecular weight, King said. "We expected the viscosity to increase with increasing molecular weight, but we found the opposite to be true when the films were thin enough."

Film thickness and molecular entanglement was the key, King said. In thick films, polymer chains are tangled together like cooked spaghetti. However, when the polymer film starts with a smaller initial thickness, a point is reached where the polymer chains change the way they interact with their neighbors. In very thin films, the polymer chains can no longer intertwine, and become like isolated blobs. This change in entanglement decreases the viscosity and increases the lateral squeeze flow.

To make the measurements, the researchers used a modified nanoscale indentation technique, which pressed a flat "punch" into very thin films of polystyrene. The punch, which was much wider than the thickness of the film, forced the polymer to flow around it. This lateral squeeze flow governs the dynamics of polymer movement during processes such as nanoimprint nanomanufacturing.

The research is a significant step forward in the understanding of polymer deformation that is directly related to nanoscale manufacturing, King said. "Our results suggest that polymer flow during nanoscale manufacturing may be enhanced by selecting polymers of higher molecular weight."

With King, co-authors of the paper are former U. of I. postdoctoral researcher Harry Rowland, and physics professor John Pethica and physics lecturer Graham Cross, both at Trinity College.

The work was funded by the Science Foundation of Ireland, the U.S. Department of Energy, and the U.S. National Science Foundation through the U. of I.'s Center for Nanoscale Chemical-Electrical-Mechanical Manufacturing Systems.


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. "Under Pressure At The Nanoscale, Polymers Play By Different Rules." ScienceDaily. ScienceDaily, 13 October 2008. <www.sciencedaily.com/releases/2008/10/081002172011.htm>.
University of Illinois at Urbana-Champaign. (2008, October 13). Under Pressure At The Nanoscale, Polymers Play By Different Rules. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/2008/10/081002172011.htm
University of Illinois at Urbana-Champaign. "Under Pressure At The Nanoscale, Polymers Play By Different Rules." ScienceDaily. www.sciencedaily.com/releases/2008/10/081002172011.htm (accessed September 19, 2014).

Share This



More Matter & Energy News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) 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:
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