Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A gel that is clearly revolutionary

23.01.2014
An innovative design turns soft hydrogels into ionic conductors with diverse applications, from artificial muscles to transparent audio speakers

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 (1).

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

Journal information

Keplinger, C., Sun, J.-Y., Foo, C. C., Rothemund, P., Whitesides, G. M. & Suo, Z. Stretchable, transparent, ionic conductors. Science 341, 984–987 (2013)

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com

More articles from Materials Sciences:

nachricht New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University

nachricht Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>