Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Recommend this page:
To (Recipient's email address)
Your name (Optional)
From (Your email address)
Message (Optional)
Datenschutz-Hinweis: Die Mailadressen werden von uns weder gespeichert noch an Dritte weitergegeben. Sie werden ausschließlich zu Übertragungszwecken verwendet.

Supersonic Spray Delivers High Quality Graphene Layer


A simple, inexpensive spray method that deposits a graphene film can heal manufacturing defects and produce a high quality graphene layer on a range of substrates, report researchers at the University of Illinois at Chicago and Korea University.

Their study is available online in the journal Advanced Functional Materials.

Photo credit: Suman Sinha-Ray

Using a supersonic spray, graphene flakes with deformed pentagonal and heptagonal structures stretch on impact and spring into a perfect hexagonal graphene lattice. This opens the way to scale up from the microscopic to large scale applications.

Graphene, a two-dimensional wonder-material composed of a single layer of carbon atoms, is strong, transparent, and an excellent conductor of electricity. It has potential in a wide range of applications, such as reinforcing and lending electrical properties to plastics; creating denser and faster integrated circuits; and building better touch screens.

Although the potential uses for graphene seem limitless, there has been no easy way to scale up from microscopic to large-scale applications without introducing defects, says Alexander Yarin, UIC professor of mechanical and industrial engineering and co-principal investigator on the study.

“Normally, graphene is produced in small flakes, and even these small flakes have defects,” Yarin said. Worse, when you try to deposit them onto a large-scale area, defects increase, and graphene’s useful properties — its “magic” — are lost, he said.

Yarin first turned to solving how to deposit graphene flakes to form a consistent layer without any clumps or spaces. He went to Sam S. Yoon, professor of mechanical engineering at Korea University and co-principal investigator on the study.

Yoon had been working with a unique kinetic spray deposition system that exploits the supersonic acceleration of droplets through a Laval nozzle. Although Yoon was working with different materials, Yarin believed his method might be used to deposit graphene flakes into a smooth layer.

Their supersonic spray system produces very small droplets of graphene suspension, which disperse evenly, evaporate rapidly, and reduce the tendency of the graphene flakes to aggregate.

But to the researchers' surprise, defects inherent in the flakes themselves disappeared, as a by-product of the spray method. The result was a higher quality graphene layer, as found in the analysis by another collaborator, Suman Sinha-Ray, senior researcher at United States Gypsum and UIC adjunct professor of mechanical and industrial engineering.

The researchers demonstrated that the energy of the impact stretches the graphene and restructures the arrangement of its carbon atoms into the perfect hexagons of flawless graphene.

“Imagine something like Silly Putty hitting a wall — it stretches out and spreads smoothly,” said Yarin. “That’s what we believe happens with these graphene flakes. They hit with enormous kinetic energy, and stretch in all directions.

"We’re tapping into graphene’s plasticity — it’s actually restructuring.”

Other attempts to produce graphene without defects or to remove flaws after manufacture have proved difficult and prohibitively expensive, Yarin said.

The new method of deposition, which allows graphene to "heal" its defects during application, is simple, inexpensive, and can be performed on any substrate with no need for post-treatment, he said.

Yarin and his Korean colleagues hope to continue their successful collaboration and foster the development of industrial-scale applications of graphene.

Jung-Jae Park, Jung-Gun Lee and You-Hong Cha of Korea University; Sang-Hoon Bae and Jong-Hyun Ahn of Yonsei University; and Yong Chae Jung and Soo Min Kim of the Korea Institute of Science and Technology are co-authors on the paper.

Initial support for the collaboration between Yarin’s group at UIC and Yoon’s group at Korean University was provided by the Office of International Affairs Nuveen International Development Fund at UIC and by Korea University.

Jeanne Galatzer-Levy | newswise
Further information:

Further reports about: Quality Spray Supersonic UIC defects deposit droplets flakes graphene kinetic

More articles from Materials Sciences:

nachricht Dimensionality transition in a newly created material
26.11.2015 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

nachricht The route to high temperature superconductivity goes through the flat land
23.11.2015 | Aalto University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Climate study finds evidence of global shift in the 1980s

Planet Earth experienced a global climate shift in the late 1980s on an unprecedented scale, fuelled by anthropogenic warming and a volcanic eruption, according to new research published this week.

Scientists say that a major step change, or ‘regime shift’, in the Earth’s biophysical systems, from the upper atmosphere to the depths of the ocean and from...

Im Focus: Innovative Photovoltaics – from the Lab to the Façade

Fraunhofer ISE Demonstrates New Cell and Module Technologies on its Outer Building Façade

The Fraunhofer Institute for Solar Energy Systems ISE has installed 70 photovoltaic modules on the outer façade of one of its lab buildings. The modules were...

Im Focus: Lactate for Brain Energy

Nerve cells cover their high energy demand with glucose and lactate. Scientists of the University of Zurich now provide new support for this. They show for the first time in the intact mouse brain evidence for an exchange of lactate between different brain cells. With this study they were able to confirm a 20-year old hypothesis.

In comparison to other organs, the human brain has the highest energy requirements. The supply of energy for nerve cells and the particular role of lactic acid...

Im Focus: Laser process simulation available as app for first time

In laser material processing, the simulation of processes has made great strides over the past few years. Today, the software can predict relatively well what will happen on the workpiece. Unfortunately, it is also highly complex and requires a lot of computing time. Thanks to clever simplification, experts from Fraunhofer ILT are now able to offer the first-ever simulation software that calculates processes in real time and also runs on tablet computers and smartphones. The fast software enables users to do without expensive experiments and to find optimum process parameters even more effectively.

Before now, the reliable simulation of laser processes was a job for experts. Armed with sophisticated software packages and after many hours on computer...

Im Focus: Quantum Simulation: A Better Understanding of Magnetism

Heidelberg physicists use ultracold atoms to imitate the behaviour of electrons in a solid

Researchers at Heidelberg University have devised a new way to study the phenomenon of magnetism. Using ultracold atoms at near absolute zero, they prepared a...

All Focus news of the innovation-report >>>



Event News

Fraunhofer’s Urban Futures Conference: 2 days in the city of the future

25.11.2015 | Event News

Gluten oder nicht Gluten? Überempfindlichkeit auf Weizen kann unterschiedliche Ursachen haben

17.11.2015 | Event News

Art Collection Deutsche Börse zeigt Ausstellung „Traces of Disorder“

21.10.2015 | Event News

Latest News

Using sphere packing models to explain the structure of forests

26.11.2015 | Ecology, The Environment and Conservation

Dimensionality transition in a newly created material

26.11.2015 | Materials Sciences

Revealing glacier flow with animated satellite images

26.11.2015 | Earth Sciences

More VideoLinks >>>