Irish scientists discover how to mass produce graphene

[jimmy olsen]

Awesome news! 

http://www.abc.net.au/science/articles/2014/04/21/3989004.htm

Lab blends up 'wonder' nanomaterial

Monday, 21 April 2014
AFP

Graphene is the world's thinnest substance, transparent but stronger than steel

    Graphene boosts energy storage potential, Science Online, 05 Aug 2013
    Physicists get close-up view of graphene, Science Online, 26 Jul 2011
    Carbon coming to a TV screen near you, Science Online, 01 Apr 2009

Graphene has been touted as a wonder material — the world's thinnest substance, but super-strong. Now scientists say it is so easy to make you could produce some in your kitchen.

Thus far, graphene has proven elusively hard to manufacture on an industrial scale. Methods have required a choice between high-quality graphene in small quantities, or large batches with defects.

Now a team from England and Ireland, report that they had used a blender to make microscopic sheets of graphene.

They placed powdered graphite, the stuff from which pencil lead is made, into a container with an "exfoliating liquid", and then mixed at high speed.

The result is miniscule sheets of graphene, each about a nanometre (a billionth of a metre) thick and 100 nanometres long, suspended in a liquid.

The force generated by the rotating blades separated the graphite into graphene layers without damaging their two-dimensional structure.

"We developed a new way of making graphene sheets," says Trinity College Dublin chemical physics professor Jonathan Coleman, who co-authored the study in the journal Nature Materials.

"This method gives lots of graphene with no defects."

The team used industrial equipment called shear mixers, but successfully repeated the experiment with a kitchen blender.

The liquid so produced can be spread onto surfaces as films of graphene sheets, like paint, or mixed with plastics to produce reinforced, composite materials.

"In the lab, we produced grams. However, when scaled up, tonnes will be produced," says Coleman.

Graphene is the world's thinnest substance, transparent but stronger than steel — a conductive super-material made of carbon just one atom thick.

There is a surge of interest in it to replace semiconductors in next-generation computers, touch screens, batteries and solar cells.

Graphene was aired as a theoretical substance in 1947. But for decades, physicists thought it would be impossible to isolate, as such thin crystalline sheets were bound to be unstable.

The problem was resolved in 2004 by a pair of scientists who used ordinary sticky tape to lift a layer from a piece of graphite.

That layer was itself pulled apart using more tape, and the process repeated until just the thinnest of layers remained — a graphene sheet.

Coleman says a company that sponsored the study has applied for a patent on the new method.

[Monoriu]

Sounds like transparent aluminum in Star Trek Movie 4 

[Syt]

Graphene was aired as a theoretical substance in 1947. But for decades, physicists thought it would be impossible to isolate, as such thin crystalline sheets were bound to be unstable.

The problem was resolved in 2004 by a pair of scientists who used ordinary sticky tape to lift a layer from a piece of graphite.

I wonder how that thought process went, and how many eyes were rolled at the suggestion of using sticky tape.

Brain: "It's impossible! It can't be done! No one can isolate a graphene sheet from graphite!"
Pinky: "Have you tried sticky tape? I use it to pick lint from my belly button! Narf!"

[KRonn]

I'm not sure if I've heard of graphene before. Probably but it was likely just theoretical stuff. So this looks immensely interesting and promising if the substance can now be created on a mass scale!

[HVC]

Isn't graphene carcinogenic? Or am I misremembering?

[The Brain]

Isn't graphene carcinogenic? Or am I misremembering?

They're Irish. I don't think this will be a problem.

[Razgovory]

I remember buys a lot of graphene paper for geometry and trigonometry classes.

[derspiess]

I was always pretty bad at graphene.

[Ed Anger]

I remember buys a lot of graphene paper for geometry and trigonometry classes.

I used it to map dungeons.

[Razgovory]

I developed an intense hatred of triangles.  There's no yield signs Cole county anymore, and some day I'll tell you all why.

[grumbler]

I was always pretty bad at graphene.

Luckily, there are calculators made out of the stuff to make graphene easier.

[jimmy olsen]

I'm not sure if I've heard of graphene before.

I think you said this the last time I posted on graphene. 

[derspiess]

I was always pretty bad at graphene.

Luckily, there are calculators made out of the stuff to make graphene easier.

I did have a graphene calculator but I played games on it more than anything

[jimmy olsen]

MIT has discovered how to make sheets of the material.

http://news.mit.edu/2018/manufacturing-graphene-rolls-ultrathin-membranes-0418

MIT engineers have developed a continuous manufacturing process that produces long strips of high-quality graphene.

The team's results are the first demonstration of an industrial, scalable method for manufacturing high-quality graphene that is tailored for use in membranes that filter a variety of molecules, including salts, larger ions, proteins, or nanoparticles. Such membranes should be useful for desalination, biological separation, and other applications.

"For several years, researchers have thought of graphene as a potential route to ultrathin membranes," says John Hart, associate professor of mechanical engineering and director of the Laboratory for Manufacturing and Productivity at MIT. "We believe this is the first study that has tailored the manufacturing of graphene toward membrane applications, which require the graphene to be seamless, cover the substrate fully, and be of high quality."

Hart is the senior author on the paper, which appears online in the journal Applied Materials and Interfaces. The study includes first author Piran Kidambi, a former MIT postdoc who is now an assistant professor at Vanderbilt University; MIT graduate students Dhanushkodi Mariappan and Nicholas Dee; Sui Zhang of the National University of Singapore; Andrey Vyatskikh, a former student at the Skolkovo Institute of Science and Technology who is now at Caltech; and Rohit Karnik, an associate professor of mechanical engineering at MIT.

Growing graphene

For many researchers, graphene is ideal for use in filtration membranes. A single sheet of graphene resembles atomically thin chicken wire and is composed of carbon atoms joined in a pattern that makes the material extremely tough and impervious to even the smallest atom, helium.

Researchers, including Karnik's group, have developed techniques to fabricate graphene membranes and precisely riddle them with tiny holes, or nanopores, the size of which can be tailored to filter out specific molecules. For the most part, scientists synthesize graphene through a process called chemical vapor deposition, in which they first heat a sample of copper foil and then deposit onto it a combination of carbon and other gases.

Graphene-based membranes have mostly been made in small batches in the laboratory, where researchers can carefully control the material's growth conditions. However, Hart and his colleagues believe that if graphene membranes are ever to be used commercially they will have to be produced in large quantities, at high rates, and with reliable performance.

"We know that for industrialization, it would need to be a continuous process," Hart says. "You would never be able to make enough by making just pieces. And membranes that are used commercially need to be fairly big ­— some so big that you would have to send a poster-wide sheet of foil into a furnace to make a membrane."

A factory roll-out

The researchers set out to build an end-to-end, start-to-finish manufacturing process to make membrane-quality graphene.

The team's setup combines a roll-to-roll approach — a common industrial approach for continuous processing of thin foils — with the common graphene-fabrication technique of chemical vapor deposition, to manufacture high-quality graphene in large quantities and at a high rate. The system consists of two spools, connected by a conveyor belt that runs through a small furnace. The first spool unfurls a long strip of copper foil, less than 1 centimeter wide. When it enters the furnace, the foil is fed through first one tube and then another, in a "split-zone" design.

While the foil rolls through the first tube, it heats up to a certain ideal temperature, at which point it is ready to roll through the second tube, where the scientists pump in a specified ratio of methane and hydrogen gas, which are deposited onto the heated foil to produce graphene.

"Graphene starts forming in little islands, and then those islands grow together to form a continuous sheet," Hart says. "By the time it's out of the oven, the graphene should be fully covering the foil in one layer, kind of like a continuous bed of pizza."

As the graphene exits the furnace, it's rolled onto the second spool. The researchers found that they were able to feed the foil continuously through the system, producing high-quality graphene at a rate of 5 centimers per minute. Their longest run lasted almost four hours, during which they produced about 10 meters of continuous graphene.

"If this were in a factory, it would be running 24-7," Hart says. "You would have big spools of foil feeding through, like a printing press."

Flexible design

Once the researchers produced graphene using their roll-to-roll method, they unwound the foil from the second spool and cut small samples out. They cast the samples with a polymer mesh, or support, using a method developed by scientists at Harvard University, and subsequently etched away the underlying copper.

"If you don't support graphene adequately, it will just curl up on itself," Kidambi says. "So you etch copper out from underneath and have graphene directly supported by a porous polymer — which is basically a membrane."

The polymer covering contains holes that are larger than graphene's pores, which Hart says act as microscopic "drumheads," keeping the graphene sturdy and its tiny pores open.

The researchers performed diffusion tests with the graphene membranes, flowing a solution of water, salts, and other molecules across each membrane. They found that overall, the membranes were able to withstand the flow while filtering out molecules. Their performance was comparable to graphene membranes made using conventional, small-batch approaches.

The team also ran the process at different speeds, with different ratios of methane and hydrogen gas, and characterized the quality of the resulting graphene after each run. They drew up plots to show the relationship between graphene's quality and the speed and gas ratios of the manufacturing process. Kidambi says that if other designers can build similar setups, they can use the team's plots to identify the settings they would need to produce a certain quality of graphene.

"The system gives you a great degree of flexibility in terms of what you'd like to tune graphene for, all the way from electronic to membrane applications," Kidambi says.

Looking forward, Hart says he would like to find ways to include polymer casting and other steps that currently are performed by hand, in the roll-to-roll system.

"In the end-to-end process, we would need to integrate more operations into the manufacturing line," Hart says. "For now, we've demonstrated that this process can be scaled up, and we hope this increases confidence and interest in graphene-based membrane technologies, and provides a pathway to commercialization."

[crazy canuck]

Graphene was aired as a theoretical substance in 1947. But for decades, physicists thought it would be impossible to isolate, as such thin crystalline sheets were bound to be unstable.

The problem was resolved in 2004 by a pair of scientists who used ordinary sticky tape to lift a layer from a piece of graphite.

I wonder how that thought process went, and how many eyes were rolled at the suggestion of using sticky tape.

Brain: "It's impossible! It can't be done! No one can isolate a graphene sheet from graphite!"
Pinky: "Have you tried sticky tape? I use it to pick lint from my belly button! Narf!"