Stretchable electronics that quadruple in length

February 29, 2016

EPFL researchers have developed conductive tracks that can be bent and stretched up to four times their original length. They could be used in artificial skin, connected clothing and on-body sensors.

Conductive tracks are usually hard printed on a board. But those recently developed at EPFL are altogether different: they are almost as flexible as rubber and can be stretched up to four times their original length and in all directions. And they can be stretched a million times without cracking or interrupting their conductivity. The invention is described in an article published today in the journal Advanced Materials.

Both solid and flexible, this new metallic and partially liquid film offers a wide range of possible applications. It could be used to make circuits that can be twisted and stretched – ideal for on prosthetics or robotic machines. It could also be integrated into fabric and used in connected clothing. And because it follows the shape and movements of the human body, it could be used for sensors designed to monitor particular biological functions.

"We can come up with all sorts of uses, in forms that are complex, moving or that change over time," said Hadrien Michaud, a PhD student at the Laboratory for Soft Bioelectronic Interfaces (LSBI) and one of the study authors.

The video will load shortly

Extensive research has gone into developing an elastic electronic circuit. It is a real challenge, as the components traditionally used to make circuits are rigid. Applying liquid metal to a thin film in polymer supports with elastic properties naturally seems like a promising approach.

Thin and reliable

Owing to the high surface tension of some of these liquid metals, experiments conducted so far have only produced relatively thick structures. "Using the deposition and structuring methods that we developed, it's possible to make tracks that are very narrow – several hundredths of a nanometer thick – and very reliable," said Stéphanie Lacour, holder of the Bertarelli Foundation Chair in Neuroprosthetic Technology and who runs the lab.

Apart from their unique fabrication technique, the researchers' secret lies in the choice of ingredients, an alloy of gold and gallium. "Not only does gallium possess good electrical properties, but it also has a low melting point, around 30o," said Arthur Hirsch, a PhD student at LSBI and co-author of the study. "So it melts in your hand, and, thanks to the process known as supercooling, it remains liquid at room temperature, even lower." The layer of gold ensures the gallium remains homogeneous, preventing it from separating into droplets when it comes into contact with the polymer, which would ruin its conductivity.

Explore further: Researchers use liquid metal to create wires that stretch eight times their original length

More information: Arthur Hirsch et al. Intrinsically Stretchable Biphasic (Solid-Liquid) Thin Metal Films, Advanced Materials (2016). DOI: 10.1002/adma.201506234

Related Stories

Air bubbles could be the secret to artificial skin

June 7, 2013

(Phys.org) —Using foam substrates, EPFL scientists were able to make a flexible electronic circuit board. This discovery could lead to the creation of deformable and stretchable circuits.

Resin film for stretchable electronics

December 28, 2015

Panasonic Corporation announced today that the company has developed a soft, flexible, and stretchable polymer resin film using its proprietary stretchable resin technology. The Company will also provide a transparent electrode ...

Recommended for you

Graphene photodetector enhanced by fractal golden 'snowflake'

January 16, 2017

(Phys.org)—Researchers have found that a snowflake-like fractal design, in which the same pattern repeats at smaller and smaller scales, can increase graphene's inherently low optical absorption. The results lead to graphene ...

Nanoscale view of energy storage

January 16, 2017

In a lab 18 feet below the Engineering Quad of Stanford University, researchers in the Dionne lab camped out with one of the most advanced microscopes in the world to capture an unimaginably small reaction.

Scientists create first 2-D electride

January 11, 2017

(Phys.org)—Researchers have brought electrides into the nanoregime by synthesizing the first 2D electride material. Electrides are ionic compounds, which are made of negative and positive ions. But in electrides, the negative ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.