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Graphene and the Coronavirus

Posted By Graphene Council, Friday, March 20, 2020

These are scary times, aren't they? First and foremost, my thoughts and prayers go out to anyone who is directly affected by the current global crisis caused by the SARS-CoV-2 coronavirus. It's an extremely serious issue that will require worldwide cooperation to overcome.

I have very clear and distinct memories of the previous SARS epidemic. In March 2003, while working at Rice University, I was helping to lead a group of ~50 science and engineering students on an overseas study trip to Hong Kong and Singapore with my former Rice colleague, Dr. Cheryl Matherly (who is now at Lehigh University). We were caught in the middle of the rapidly developing crisis and our travel itinerary had us departing Singapore for Hong Kong on the day the Singapore government warned its own citizens not to travel to Hong Kong!

Fortunately, everyone in our student group made it through that experience safely, and as unsettling as it was, the current situation is much much worse, with as yet unknown - but sure to be significant - social, economic and political ramifications that will most definitely impact future generations around the world.

I am currently based in Bangkok, Thailand, which is a global tourist destination. While we were fortunately to escape the first wave of of the SARS-CoV-2 virus that emanated from China, we're now faced with a second wave imported from Europe. We're not quite under total lockdown here, but things appear to be headed in that direction. It is clear to me form observation that the several governments in the region (Singapore, Hong Kong, and Taiwan, to be specific) are applying the lessons they learned from the previous SARS epidemic to help control the current pandemic. This give me hope, and the circumstances in general have given me plenty of time to think and reflect about what - if anything - I and my company, planarTECH, can do to improve this situation.

Graphene: The "Wonder Material"

I was lucky to fall into the world of graphene and 2D materials by accident through acquaintance with another former Rice University colleague, Dr. James Tour, and conversations I had with him 8 years ago. I will not spend a lot of time here talking about the specific properties of graphene as such information is widely available. The European Union's Graphene Flagship project, for example, has an excellent overview. The University of Manchester - where graphene was first isolated and where planarTECH's Chairman, Ray Gibbs, currently serves as the Director of Commercialization for the Graphene Engineering and Innovation Centre - also has a fantastic YouTube channel with many instructive videos about graphene and its properties.

With all of the amazing properties of graphene, the question is, can it offer any kind of solution to the current pandemic and global crisis?

Academic Work: Graphene's Antiviral Properties

The short answer to the question above is "possibly," but with some caveats. In particular, it would appear that graphene oxide (GO) may play a role in providing a solution.

I should say that I am not a doctor, an epidemiologist or someone with formal training in the biological sciences. I am an engineer by trade, and for the last 8 years, an entrepreneur in the field of graphene. However, since entering the graphene industry, I have grown accustomed to reading academic papers in order to understand the potential applications for graphene.

A paper published in 2015 by researchers at the Huazhong Agricultural University (ironically located in Wuhan, China, where the current pandemic originated) explored the antiviral properties of graphene oxide, and the authors of the paper concluded "that GO and rGO exhibit broad-spectrum antiviral activity toward both DNA virus (PRV) and RNA virus (PEDV) at a noncytotoxic concentration," and that "the broad-spectrum antiviral activity of GO and rGO may shed some light on novel virucide development." While encouraging, it should be noted that the researchers looked specifically at pseudorabies virus (PRV) and porcine epidemic diarrhea virus (PEDV), not the SARS-CoV-2 virus responsible for the current global pandemic.

Another paper published in 2017 by researchers at Southwest University in China looked at cyclodextrin functionalized graphene oxide and it's possible role in combatting respiratory syncytial virus (RSV), concluding that "the curcumin loaded functional GO was confirmed with highly efficient inhibition for RSV infection and great biocompatibility to the host cells." Likewise, a third paper published in 2019 by researchers at Sichuan Agricultural University in China demonstrated that "GO/HY [graphene oxide/hypericin] has antiviral activity against NDRV [novel duck reovirus] both in vitro and in vivo."

The conclusion we can draw from these works is that graphene oxide may offer a platform to fight a variety of viral infections (such as the SARS-CoV-2 coronavirus), possibly as some form of coating, though certainly more work needs to be done.

(Note that my good friends over at The Graphene Council had a recent and excellent blog post covering the same 3 articles in a little more detail. And kudos to them for shining light on the topic before me!)
Productization: From Lab to Market

If there's one thing I've learned from the past 8 years being involved with graphene commercialization (and the past 14 years working directly in the Asian supply chain) is that it is one matter to write an excellent academic paper as a proof-of-concept, but it is an entirely different matter to take work from an academic lab and turn it into a real product.

With respect to graphene in general, what we are seeing today is definite movement on the Gartner hype cycle from the Trough of Disillusionment to the Slope of Enlightenment. Real products using graphene are now on the market. One such example is the recent announcement of of a collaboration between UK-based Haydale Graphene Industries plc and Korea-based ICRAFT Co., Ltd. that results in the release of a graphene cosmetic face mask. And I am pleased to be able to say that - in connection with my previous responsibilities for Haydale's Asia-Pacific operations - I had some role (together with my colleague Yong-jae "James" Ji) in getting this product off the ground and into the marketplace.

While this may seem like a trivial accomplishment given the context and seriousness of the current global pandemic, I offer this example as proof that graphene can be utilized in an everyday, cost-sensitive product, and it is not such a great conceptual leap to go from a cosmetic face mask to a protective face mask, which as we all know are in great demand these days (especially here in Asia). I would invite iCRAFT (or anyone else) to consider collaboration with planarTECH to develop such a product. (Above photo courtesy of Macau Photo Agency on Unsplash.)

Productization: Existing Products?

Very much related to this topic and very curious is a recent public announcement by LIGC Applications of its Guardian G-Volt face mask with a graphene-based filtration system. However, my understanding is that LIGC is not employing graphene specifically for it's potential antiviral properties but rather for its potential to enhance a filtration system, including (due to graphene's electrical conductivity) the ability to pass an electrical charge through the mask that "would repel any particles trapped in the graphene mask."

What I find very curious about this case is that subsequent to this announcement, LIGC's Indiegogo crowdfunding campaign, which was live, has now been placed under review, and the company's pitch video on YouTube has likewise been made private. I do not know what has happened here - perhaps is was perceived as poor timing? - but as a fellow entrepreneur who is conducting my own crowdfunding campaign, I wish LIGC the best of luck with its product development and ultimate launch. I definitely want to see more viable graphene products in the marketplace.

The Graphene Supply Chain: planarTECH's Role

One of the challenges the graphene industry faces overall is scalability. Very few graphene companies today (if any at all) can produce graphene at the scale, at the right cost, and with the consistent quality such that it can be used for truly high-volume applications. Over the past 8 years, I have met numerous customers, mostly in Asia, who want to use graphene in their products but cannot find a secure and stable supply that meets their expectations on specification, volume, and price.

At planarTECH we're interested in not only the end applications, but also in solving this problem of production scalability. While we have in the past mainly been focused on production systems for graphene and other 2D materials by Chemical Vapor Deposition (CVD), we also recently started offering continuous flow production systems for graphene oxide, which we believe can take graphene oxide production from lab-scale, high-cost (grams per week) to production-scale, low-cost (kilograms per hour). We're actively seeking partners to work with us on setting up production and exploration of the application space for graphene oxide, and we're currently conducting a crowdfunding campaign on Seedrs to help us expand our business and make graphene a commercial reality. As seen above, we think graphene oxide's antiviral properties can be exploited to make new and useful products.

I should clarify and caution that planarTECH is not in the position today to offer a graphene-based product that can immediately help alleviate current crisis and prevent widespread infection. Unfortunately, such a product is realistically 1-2 years away. But what we can offer is market expertise specific to graphene, production technologies, and experience in taking products from the idea phase to a reality in the marketplace.

Conclusion: Graphene is a Possible Solution

To conclude, I would like to reiterate a few broad points.

• Graphene (graphene oxide in particular) and coatings made from graphene would appear to have antiviral properties as reported in several published academic papers.
• Real commercial products exist that use graphene, but the industry as a whole still faces challenges around scalability, cost and quality.
• An immediate graphene-based solution to alleviate the effects of the global SARS-CoV-2 coronavirus pandemic is likely unrealistic, but could be possible in the future.
• planarTECH has a role in the supply chain and is seeking partners, as well as investors via its crowdfunding campaign, to expand its business and help end customers develop useful products.

Tags:  2D materilas  chemical vapour deposition  Cheryl Matherly  Graphene  Graphene Engineering and Innovation Centre  Graphene Flagship  graphene oxide  Healthcare  J. Patrick Frantz  James Tour  Lehigh University  planarTECH  Ray Gibbs  Rice University  Yong jae Ji 

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Graphene’s ultimate stretchability and ‘realistic’ strength discovered

Posted By Graphene Council, Wednesday, March 11, 2020
The realistic mechanical properties of monolayer graphene have been successfully studied by a new method developed by a research team led by Dr Lu Yang, Associate Professor of Department of Mechanical Engineering at City University of Hong Kong (CityU). The groundbreaking discovery will promote the application of graphene in different areas, such as the touch monitor on flexible mobile phones.

Dr Lu’s research achievement has been published in the prestigious international journal Nature Communications, titled “Elastic straining of free-standing monolayer graphene.” This paper was also highlighted in “Editors' Choice” in the 21 February 2020 issue of Science.

A two-dimensional carbon substance, graphene is the strongest material known with excellent electrical and thermal conductivity. Hence, it is deemed a "super material", ideal for many fields, for example, transistors, biosensors and batteries.

Graphene’s structure as a single layer of atoms has made it extremely difficult for scientists to test its actual mechanical properties such as elasticity and tensile strength. The studies in this area so far have covered only its ideal limits by local indentation experiments and theoretical calculations.

“No one has really stretched a large-area, free-standing monolayer graphene and tested its elastic tensile properties,” Dr Lu said.

Over the years, Dr Lu has researched the mechanical properties of various nanomaterials. His research team has successfully developed a new method for transferring large-area graphene onto his unique nanomechanical testing platform, performing in situ tensile tests in a scanning electron microscope to study changes in stretching and shaping.

“One major challenge in our study is how to transfer and lay an extremely light and thin monolayer graphene sample onto a testing platform without damage, and apply the strain evenly when stretching it,” Dr Lu said.

The experiment showed that the tensile strength of chemical vapour deposition (CVD)-grown monolayer graphene can reach 50 to 60 GPa (gigapascal), with elastic strain up to 6%, and the measured Young’s modulus (or the “elastic modulus”) is 920 GPa, which is very close to the theoretical value of ~1,000 GPa. Pascals are units of measurement for stress.

“It took us nearly four years to overcome a lot of difficulties for the experiment, but our work has revealed the realistic mechanical properties of graphene for engineering relevance,” Dr Lu said.

Its strength and stretchability make graphene a suitable material for manufacturing flexible electronic devices, such as transistors with better robustness, organic light-emitting diodes, and other mechanical components.

It can also be used for the production of composite materials and in the areas of biomedical research, aviation and national defence.

Dr Lu said he was grateful to CityU for providing top-notch facilities for his team to conduct their research, such as the Nano-Manufacturing Laboratory at the CityU Shenzhen Research Institute, the Centre for Super-Diamond and Advanced Films, and the Centre for Advanced Structural Materials.

In addition, CityU’s emphasis on interdisciplinary collaboration helped his research. “Our experiment required experts from the disciplines of mechanics, materials science, chemistry and physics to work together, and the outstanding talents in these fields can be readily found at CityU,” Dr Lu said.

Members of the research team include PhD students Cao Ke and Han Ying in the Department of Mechanical Engineering and Dr Ly Thuc-hue, Assistant Professor in the Department of Chemistry, at CityU, as well as experts from Tsinghua University and Xidian University.

Tags:  chemical vapour deposition  City University of Hong Kong  Electronics  Graphene  Lu Yang  monolayer graphene 

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Grain boundaries in graphene do not affect spin transport

Posted By Graphene Council, Wednesday, December 4, 2019
Graphene is a material that has been gaining fame in recent years due to its magnificent properties. In particular, for spintronics, graphene is a valuable material because the spins of the electrons used remain unaltered for a relatively long time. However, graphene needs to be produced on a large scale in order to be used in future devices. With that respect, chemical vapour deposition (CVD) is the most promising fabrication method.

CVD involves growing graphene on a metallic substrate at high temperatures. In this process, the generation of graphene starts at different points of the substrate simultaneously. This produces different single-crystal domains of graphene separated from one another through grain boundaries, consisting of arrays of five-, seven- or even eight-member carbon rings. The final product is, thus, polycrystalline graphene.

Is polycrystalline graphene as good as single-crystal graphene for spintronics? Grain boundaries are a significant source of charge scattering, increasing the electric resistance of the material. How do they affect spin transport?

Some experiments suggest that grain boundaries do not play a major role on spin transport. In this context, Dr Aron W. Cummings, from the ICN2 Theoretical and Computational Nanoscience Group, led by ICREA Prof. Stephan Roche, together with researchers from the Université catholique de Louvain (Belgium), have used first-principles simulations to study the impact of grain boundaries on spin transport in polycrystalline graphene. The study is published in Nano Letters.

The researchers have considered two different mechanisms by which spins could lose their original orientation (spin relaxation). One accounts for the randomisation of spins within the grains due to spin-orbit coupling, the other considers the possibility of the spins to flip due to scattering in a grain boundary. However, the researchers found that the latter case did not happen. Grain boundaries do not have any adverse effect on spin transport.

Therefore, spin diffusion length in polycrystalline graphene is independent of grain size and depends only on the strength of the substrate-induced spin-orbit coupling. Moreover, this is valid not only for the diffusive regime of transport, but also for the weakly localized one, in which quantum phenomena begin to prevail. This is the first quantum mechanical simulation confirming that the same expression for spin diffusion length holds in both regimes.

The research highlights the fact that single-domain graphene may not be a requirement for spintronics applications, and that polycrystalline CVD-grown graphene may work just as well. This puts the focus on other aspects to enhance in graphene production, such as the elimination of magnetic impurities.

Tags:  Aron W. Cummings  chemical vapour deposition  CVD  Graphene  Nano Letters  Nanoscience  polycrystalline  Stephan Roche  Universite catholique de Louvain 

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