Featured Research

from universities, journals, and other organizations

Soft hydrogels turned into ionic conductors with diverse applications, from artificial muscles to transparent speakers

Date:
January 22, 2014
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
An innovative design turns soft hydrogels into ionic conductors with diverse applications, from artificial muscles to transparent audio speakers.

An innovative design turns soft hydrogels into ionic conductors with diverse applications, from artificial muscles to transparent audio speakers.

Related Articles


Researchers are determined to manufacture stretchable biomedical devices that interface directly with organs such as the skin, heart and brain. Electronic devices, however, are usually made from hard materials that are incompatible with soft tissue. Choon Chiang Foo from the A*STAR Institute of High Performance Computing, Singapore, and researchers at Harvard University, United States, are aiming to solve this dilemma with squishy, see-through gels that can act as integral components of stretchable devices thanks to an innovative ionic conduction mechanism.

Foo and co-workers made their discovery while investigating a promising 'artificial muscle' technology known as dielectric elastomers. These devices sandwich an insulating rubber polymer between two conductive electrodes, typically made from micro-cracked metals or carbon grease. Applying a voltage to the electrodes builds up pressure which causes the inner polymer to expand. Most electrode materials, however, begin to lose conductivity when subjected to high strains.

The researchers chose to replace the electrodes in dielectric elastomers with soft hydrogels. Hydrogels are transparent and biocompatible materials, typically used in contact lenses, which encapsulate salty ions and water inside a polymeric sheath. Replacing the electrodes requires overcoming two well-known limitations of ionic conductors: their slow speeds relative to electron conductors and a tendency to undergo destructive electrochemical reactions at high voltages.

The team's setup addresses these problems by placing a thin insulating rubber sheet between two hydrogel layers. Electric signals sent to the hydrogel through tiny electrodes leads to rapid buildup of oppositely charged ions on each side of the rubber sheet causing the sandwiched device to thin and expand over the entire area. Furthermore, the rubber layer has a remarkably low capacitance, which causes a large voltage drop across the rubber and shields the hydrogel from electrochemical reactions, even at kilovolt ranges.

To demonstrate the high-frequency operation of their stretchable ionic material, the researchers produced the world's first gel-based transparent loudspeaker (see image). This device, which could be placed over a smartphone or flat-screen television screen, resonated thousands of times per second over the entire audible range.

Foo, whose theoretical contributions proved critical to understanding the novel behavior of these stretchy gels, believes this work may lead to a fundamental shift in how engineers conceive electronic devices. "Because existing conductors struggle to meet the demands of stretchable applications, device designers may begin to ask if they can replace electronic conductors with ionic conductors," he explains.

"The device may lose some performance but may gain other attributes, such as stretchiness, transparency and biocompatibility."

The A*STAR-affiliated researcher contributing to this research is from the Institute of High Performance Computing.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. C. Keplinger, J.-Y. Sun, C. C. Foo, P. Rothemund, G. M. Whitesides, Z. Suo. Stretchable, Transparent, Ionic Conductors. Science, 2013; 341 (6149): 984 DOI: 10.1126/science.1240228

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Soft hydrogels turned into ionic conductors with diverse applications, from artificial muscles to transparent speakers." ScienceDaily. ScienceDaily, 22 January 2014. <www.sciencedaily.com/releases/2014/01/140122092447.htm>.
The Agency for Science, Technology and Research (A*STAR). (2014, January 22). Soft hydrogels turned into ionic conductors with diverse applications, from artificial muscles to transparent speakers. ScienceDaily. Retrieved April 17, 2015 from www.sciencedaily.com/releases/2014/01/140122092447.htm
The Agency for Science, Technology and Research (A*STAR). "Soft hydrogels turned into ionic conductors with diverse applications, from artificial muscles to transparent speakers." ScienceDaily. www.sciencedaily.com/releases/2014/01/140122092447.htm (accessed April 17, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Friday, April 17, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Electric Rover Goes for a Spin

NASA Electric Rover Goes for a Spin

Reuters - Innovations Video Online (Apr. 17, 2015) NASA&apos;s prototype electric buggy could influence future space rovers and conventional cars. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Scientists Create Self-Powering Camera

Scientists Create Self-Powering Camera

Reuters - Innovations Video Online (Apr. 17, 2015) American scientists build a self-powering camera that captures images without using an external power source, allowing it to operate indefinitely in a well-lit environment. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
The State Of Virtual Reality

The State Of Virtual Reality

Newsy (Apr. 17, 2015) Virtual Reality is still a young industry. What’s on offer and what should we expect from our immersive new future? Video provided by Newsy
Powered by NewsLook.com
Tackling Congestion in the World's Worst Traffic City

Tackling Congestion in the World's Worst Traffic City

Reuters - News Video Online (Apr. 16, 2015) New transportation system and regulations aim to resolve gridlock in Jakarta, which has been named the city with the world&apos;s worst traffic. Angie Teo reports. 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:

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