Featured Research

from universities, journals, and other organizations

Droplet response to electric voltage in solids exposed

Date:
October 23, 2012
Source:
Duke University
Summary:
For the first time, scientists have observed how droplets within solids deform and burst under high electric voltages. The finding is important because it explains a major reason why such materials as insulation for electrical power lines eventually fail and cause blackouts. This observation not only helps scientists develop better insulation materials, but could also lead to such positive developments as "tunable" lenses for eyes.

This shows the deformation of a droplet as the voltage increases.
Credit: Xuanhe Zhao

For the first time, scientists have observed how droplets within solids deform and burst under high electric voltages.

This is important, the Duke University engineers who made the observations said, because it explains a major reason why such materials as insulation for electrical power lines eventually fail and cause blackouts. This observation not only helps scientists develop better insulation materials, but could also lead to such positive developments as "tunable" lenses for eyes.

As the voltage increases, water droplets, or air bubbles, within polymers slowly change from their spherical shape to a more tubular shape, causing extremely large deformation within the material. Over time, this can lead to cracking and failure of the polymer, the researchers said. Polymers are a class of "soft" materials that can be found almost everywhere, most commonly as an insulator for electrical wires, cables and capacitors. Droplets or bubbles can be trapped in these polymers as defects during fabrication.

"The effects of electric voltage on droplets in air or in liquid have been studied over decades,' said Xuanhe Zhao, assistant professor of mechanical engineering and materials science at Duke's Pratt School of Engineering. "We take advantage of the understanding of these electrified drops in air or liquid every day, such as in the use of ink-jet printers.

"Conversely, no one has actually observed the effects of electric voltages on droplets in solids," Zhao said.

The results of Zhao's experiments were published online Oct. 23, 2012, in the journal Nature Communications. His work is supported by and the National Science Foundation's Research Triangle Materials Research Science and Engineering Center, National Science Foundation's Materials and Surface Engineering program and National Institutes of Health.

In air or liquid, droplets subjected to increased voltage tend to transform into a cone shape that eventually emits tiny droplets from the pointed end of the cone. This is the basic phenomenon that is taken advantage of in inkjet printers and similar technologies.

"Changes in electrified drops in solids have not been well studied, because it has been very difficult to observe the process as the solid would usually break down before droplet transformation could be captured," Zhao said. "This limitation has not only hampered our understanding of electrified droplets, but has hindered the development of high-energy-density polymer capacitors and other devices."

This knowledge becomes especially important, Zhao said, as scientists are developing new polymers designed to carry higher and higher loads of electricity.

Zhao's experiments involved droplets, or bubbles, encapsulated within different types of polymers. Using a special technique developed by Zhao group, the team observed and explained how increased voltage caused the droplet to form a sharp "tip" before evolving into the tubular shape.

"Our study suggests a new mechanism of failure of high-energy-density dielectric polymers," Zhao said. "This should help in the development of such applications as new capacitors for power grids or electric vehicles and muscle-like transducers for soft robots and energy harvesting."

The experiments also showed how polymers "deformed," or changed shapes, at different voltages before they failed.

"It appears that it could be possible, just by varying voltages, to change the shape of a particular polymer," Zhao said. "One of the new areas we are now looking into is creating lenses that can be custom-shaped and used in ophthalmic settings."

Other members of the team were Qiming Wang, Zhao's graduate student, and Zhigang Suo, Harvard University.


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, Zhigang Suo, Xuanhe Zhao. Bursting drops in solid dielectrics caused by high voltages. Nature Communications, 2012; 3: 1157 DOI: 10.1038/ncomms2178

Cite This Page:

Duke University. "Droplet response to electric voltage in solids exposed." ScienceDaily. ScienceDaily, 23 October 2012. <www.sciencedaily.com/releases/2012/10/121023152322.htm>.
Duke University. (2012, October 23). Droplet response to electric voltage in solids exposed. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2012/10/121023152322.htm
Duke University. "Droplet response to electric voltage in solids exposed." ScienceDaily. www.sciencedaily.com/releases/2012/10/121023152322.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Stranded Whale Watching Boat Returns to Boston

Stranded Whale Watching Boat Returns to Boston

Reuters - US Online Video (July 29, 2014) Passengers stuck overnight on a whale watching boat return safely to Boston. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Baluchistan Mining Eyes an Uncertain Future

Baluchistan Mining Eyes an Uncertain Future

AFP (July 29, 2014) Coal mining is one of the major industries in Baluchistan but a lack of infrastructure and frequent accidents mean that the area has yet to hit its potential. Duration: 01:58 Video provided by AFP
Powered by NewsLook.com
Easier Nuclear Construction Promises Fall Short

Easier Nuclear Construction Promises Fall Short

AP (July 29, 2014) The U.S. nuclear industry started building its first new plants using prefabricated Lego-like blocks meant to save time and prevent the cost overruns that crippled the sector decades ago. So far, it's not working. (July 29) 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