Featured Research

from universities, journals, and other organizations

How voltage breaks down plastic: Creasing to cratering

Date:
March 4, 2011
Source:
Duke University
Summary:
Scientists have seen for the first time how soft polymers, such as wire insulation, can break down under exposure to electrical current.

A Duke University team has seen for the first time how soft polymers, such as wire insulation, can break down under exposure to electrical current.

Researchers have known for decades that polymers, such those insulating wires, may break down due to deformation of the polymers. But the process had never been seen.

In a series of experiments, Duke University engineers have documented at the microscopic level how plastic deforms to breakdown as it is subjected to ever-increasing electric voltage. Polymers can be found almost everywhere, most commonly as an insulator for electrical wires, cables and capacitors.

The findings by the Duke engineers could help in developing new materials to improve the durability and efficiency of any polymer that must come into contact with electrical currents, as well as in the emerging field of energy harvesting.

"We have long known that these polymers will eventually break down, or fail, when subjected to an increasing electrical voltage," said Xuanhe Zhao, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. He is the senior scientist in the series of experiments performed by a graduate student Qiming Wang and published online in the Physical Review Letters. "Now we can actually watch the process as it happens in real time."

The innovation the Duke team developed was attaching the soft polymer to another rigid polymer layer, or protective substrate, which enabled observation of the deformation process without incurring the breakdown. They then subjected this polymer-substrate unit to various electrical voltages and observed the effects under a microscope.

"As bread dough rises in a bowl, the top surface of the dough may fold in upon itself to form creases due to compressive stresses developing in the dough," Zhao said, "Surprisingly, this phenomenon may be related to failures of electrical polymers that are widely used in energy-related applications."

"When the voltage reached a critical point, the compressive stress induced a pattern of creases, or folds, on the polymer," Zhao. "If the voltage is increased further, the creases evolved into craters or divots in the polymer as the electrical stress pulls the creases open. Polymers usually break down electrically immediately after the creasing, which can cause failures of insulating cables and organic capacitors."

The substrate the researchers developed for the experiments not only allowed for the visualization of the creasing-to-cratering phenomenon, it could also be the foundation of a new approach to improving the ability of wires to carry electricity.

The research was supported by startup funds provided by Pratt.


Story Source:

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


Journal Reference:

  1. Qiming Wang, Lin Zhang, and Xuanhe Zhao. Creasing to cratering instability in polymers under ultrahigh electric fields. Physical Review Letters, Accepted Feb 07, 2011

Cite This Page:

Duke University. "How voltage breaks down plastic: Creasing to cratering." ScienceDaily. ScienceDaily, 4 March 2011. <www.sciencedaily.com/releases/2011/03/110304090504.htm>.
Duke University. (2011, March 4). How voltage breaks down plastic: Creasing to cratering. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2011/03/110304090504.htm
Duke University. "How voltage breaks down plastic: Creasing to cratering." ScienceDaily. www.sciencedaily.com/releases/2011/03/110304090504.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 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:
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