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Scientists create "spray-on graphene"

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May 29, 2014

Researchers have devised a method of spraying graphene onto a wide variety of surfaces  (I...

Researchers have devised a method of spraying graphene onto a wide variety of surfaces (Image: Shutterstock)

Despite its many desirable qualities and potential applications, graphene still isn't as widely used as it could be for one main reason – it's difficult to apply to surfaces, particularly large ones. Attempting to do so often causes damage to the graphene, or otherwise results in a non-uniform, flawed coating. Now, however, scientists have devised a method of simply spraying the stuff on, that actually improves the graphene in the process.

Prof. Sam S. Yoon at Korea University had already been working on a kinetic spray deposition system, that could apply liquids to a variety of materials by accelerating droplets to supersonic speeds via a de Laval nozzle. He was approached by the University of Illinois at Chicago's Prof. Alexander Yarin, who believed that the technology could be used for the application of graphene flakes suspended in a carrier liquid.

The result of their collaboration is a system that reportedly applies graphene to various substrates in a smooth, even layer. The liquid evaporates quickly, leaving behind a coating of well-distributed flakes that resist clumping together, but that also don't have any large empty spaces between them.

While the relatively flawless overall coating was what the scientists had been hoping for, they were surprised to discover that the deposition process also corrected flaws already present in the individual flakes. This was likely due to the fact that the "imperfect" graphene was forced to stretch out in all directions as it hit the substrate at supersonic speed, its linked carbon atoms subsequently defaulting back to a more uniform, hexagonal alignment with one another.

According to Yarin, the new process is "simple, inexpensive, and can be performed on any substrate with no need for post-treatment."

A paper on the research was recently published in the journal Advanced Functional Materials. Scientists at MIT and the University of Michigan are developing another graphene deposition technique, that involves the application and subsequent removal of metal foil to the substrate.

Source: University of Illinois at Chicago

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
8 Comments

Would be interested to see the properties of the preyed on vs other processes.

My other thoughts are, can it be layered. ie, wait for coat to dry then repeat, or would this not create a second layer?

Nairda
29th May, 2014 @ 09:05 pm PDT

@Nairda - I suspect it would not as the reason this works is due to the sheets being forced to self align due to the energy of their delivery.

Combining this with the easy shearing method of adding detergent and graphite to a shearing mixer would create a simple end-to-end process that could easily scale up. This could be the beginning of industrial scale graphene.

VirtualGathis
30th May, 2014 @ 12:00 pm PDT

When will it be available in a spray can, like currently available spray on dry graphite lube?

Is this graphene coating durable? Does it reduce friction?

Gregg Eshelman
30th May, 2014 @ 02:01 pm PDT

Is there any control over the orientation of the grapheme deposition? Graphene's conductive properties rely on edge orientation (armchair vs. zig-zag) in order to have ballistic conduction. Perhaps magnetic fields would guide the spray polarity or surface boundaries serve as starting points to dictate lay out orientation.

Gary Richardson
30th May, 2014 @ 03:49 pm PDT

I wonder if you could make a ribbon microphone that won't break with this method?

esar
30th May, 2014 @ 05:01 pm PDT

If I spray the inside of an aluminized Mylar gas bag with it will the gas bag hold hydrogen long term?

Slowburn
30th May, 2014 @ 10:20 pm PDT

would it work to keep hair straight?

Antony Innit
1st June, 2014 @ 01:11 am PDT

Can I make an un breakable condom?

Andrew Zuckerman
20th July, 2014 @ 10:57 pm PDT
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