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 Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press

nachricht Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>