Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Controlled crumpling of graphene forms artificial muscle

24.01.2013
Duke University engineers are layering atom-thick lattices of carbon with polymers to create unique materials with a broad range of applications, including artificial muscles.

The lattice, known as graphene, is made of pure carbon and appears under magnification like chicken wire. Because of its unique optical, electrical and mechanical properties, graphene is used in electronics, energy storage, composite materials and biomedicine.


This is crumpled graphene.
Credit: Xuanhe Zhao

However, graphene is extremely difficult to handle in that it easily "crumples." Unfortunately, scientists have been unable to control the crumpling and unfolding of large-area graphene to take advantage of its properties.

Duke engineer Xuanhe Zhao, assistant professor in Duke's Pratt School of Engineering, likens the challenge of controlling graphene to the difference between unfolding paper and wet tissue.

"If you crumpled up normal paper, you can pretty easily flatten it out," Zhao said. "However, graphene is more like wet tissue paper. It is extremely thin and sticky and difficult to unfold once crumpled. We have developed a method to solve this problem and control the crumpling and unfolding of large-area graphene films."

The Duke engineers attached the graphene to a rubber film that had been pre-stretched to many times its original size. Once the rubber film was relaxed, parts of the graphene detached from the rubber while other parts kept adhering to it, forming an attached-detached pattern with a feature size of a few nanometers. As the rubber relaxed, the detached graphene was compressed to crumple. But as the rubber film was stretched back, the adhered spots of graphene pulled on the crumpled areas to unfold the sheet.

"In this way, the crumpling and unfolding of large-area, atomic-thick graphene can be controlled by simply stretching and relaxing a rubber film, even by hands," Zhao said.

The results were published online in the journal Nature Materials.

"Our approach has opened avenues to exploit unprecedented properties and functions of graphene," said Jianfeng Zang, a postdoctoral fellow in Zhao's group and the first author of the paper. "For example, we can tune the graphene from being transparent to opaque by crumpling it, and tune it back by unfolding it."

In addition, the Duke engineers layered the graphene with different polymer films to make a "soft" material that can act like muscle tissues by contracting and expanding on demand. When electricity is applied to the graphene, the artificial muscle expands in area; when the electricity is cut off, it relaxes. Varying the voltage controls the degree of contraction and relaxation.

"The crumpling and unfolding of graphene allows large deformation of the artificial muscle," Zang said.

"New artificial muscles are enabling diverse technologies ranging from robotics and drug delivery to energy harvesting and storage," Zhao said. "In particular, they promise to greatly improve the quality of life for millions of disabled people by providing affordable devices such as lightweight prostheses and full-page Braille displays."

Zhao's work is supported by the National Science Foundation's (NSF) Triangle Materials Research Science and Engineering Center, NSF Materials and Surface Engineering program, and National Institutes of Health (NIH). Other members of the team are Duke's Qiming Wang and Qing Tu.

Richard Merritt | EurekAlert!
Further information:
http://www.duke.edu

More articles from Materials Sciences:

nachricht Contacting the molecular world through graphene nanoribbons
19.02.2018 | Elhuyar Fundazioa

nachricht When Proteins Shake Hands
19.02.2018 | Friedrich-Schiller-Universität Jena

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>