Crumpling of graphene controlled to create artificial muscle

Washington, January 24 (ANI): 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.

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. 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," Zhao said.

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.

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

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.

The results were published online in the journal Nature Materials. (ANI)

Matches

MORE TOP STORIES TODAY

Bangalore's arsenal blazes to victory

Bangalore's arsenal blazes to victory

Yuvraj Singh was back to his best in his first match for Royal Challengers Bangalore. More »

Time for Chennai to enter familiar cocoon

Time for Chennai to enter familiar cocoon

Chennai have been able to purchase batting replacements for the loss of Michael Hussey and spin reinforcements in the form of Samuel Badree. They appear… More »

Evenly matched Rajasthan and Hyderabad face-off

Evenly matched Rajasthan and Hyderabad face-off

A quality that defines Rajasthan and Hyderabad is consistency. Rajasthan was one among two teams to enjoy complete dominance at home last season. Hyderabad… More »

BCCI to meet before next court hearing

BCCI to meet before next court hearing

The BCCI will hold an emergent working committee meeting on April 20 to discuss the future course of action with regard to the Supreme Court hearing concerning… More »

Kallis, Narine star in Knight Riders’ crushing win

Kallis, Narine star in Knight Riders’ crushing win

An all-round display saw Knight Riders thump Mumbai Indians by 41 runs in the IPL-7 opener. More »

Gavaskar wants a clean IPL

Gavaskar wants a clean IPL

"Integrity is non-negotiable..." says the BCCI's interim chief ahead of Season 7 of the tainted league. More »

'Yak' Kallis still on top of his game

'Yak' Kallis still on top of his game

The 38-year-old South African veteran turned it on for Kolkata Knight RIders in the opening match of IPL-7. More »

Srinivasan named in fixing report: SC

Srinivasan named in fixing report: SC

The court emphasised that the tainted administrator can no longer work for the BCCI. More »

Yuvraj happy to play for RCB: Kohli

Yuvraj happy to play for RCB: Kohli

New-look RCB will play their first game of IPL-7 on Thursday. More »

Shane Watson issues moral warning

Shane Watson issues moral warning

'Everyone knows what is right and what is wrong and if you do the wrong thing it will be found out' More »

Why I'm not looking forward to the IPL

Why I'm not looking forward to the IPL

Welcome to another season of a league that many watch but few trust. More »

IPL: News Line

IPL: News Line

A round-up of all the news from this season of the IPL. More »

Johnson may quit T20s for Tests

Johnson may quit T20s for Tests

Australia's Mitchell Johnson may quit limited-overs cricket to prolong his test career with an eye on the 2015 Ashes series in England, the fast bowler… More »

Nepal players call off boycott

Nepal players call off boycott

Thaw in relations after formation of an advisory committee that would work in tandem with the Cricket Association of Nepal. More »

There's a lot going on: Fleming

There's a lot going on: Fleming

He experienced anxious moments in the lead-up to the tournament as the courts decided on whether to suspend the franchise, he said, but stressed that the… More »

Latif couldn’t work with tainted players

Latif couldn’t work with tainted players

Former Pakistan cricket captain Rashid Latif said Tuesday he turned down the job of national chief selector because he could not work with ex-players tainted… More »

We are not over-confident: Bailey

We are not over-confident: Bailey

Indian Premier League — George Bailey-led Kings XI Punjab will face Chennai Super Kings on Friday. More »

Big runs expected, with bat and ball

Big runs expected, with bat and ball

Royal Challengers Bangalore: Their main concern, once again, is the fast bowling More »

Taxing issue — BCCI hits roadblock

Taxing issue — BCCI hits roadblock

MoU between BCCI & its units to avoid double taxation delayed after a few decline to share details. More »

Black Caps pick rookie duo for West Indies

Black Caps pick rookie duo for West Indies

New Zealand selectors included two new caps in a 15-man Test squad named Tuesday to tour the West Indies, with injury-hit spinner Dan Vettori's future… More »

The stage is set for IPL-7 to start

The stage is set for IPL-7 to start

The Preview — Defending champions Mumbai Indians take on Kolkata Knight Riders More »

Srinivasan appeals to court to allow BCCI comeback

Srinivasan appeals to court to allow BCCI comeback

He was aggrieved by the allegations against him during the hearing. More »

India: cricket's Brazil

India: cricket's Brazil

They are tough to beat with a big talent base exposed to good facilities. (CYCSPL) More »

Delhi Daredevils say no to gifts

Delhi Daredevils say no to gifts

Franchises are doing their bit to refurbish the image of the tainted league. More »