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Graphene Nanoplatelets: a future role in pipecoating?

Posted By Graphene Council, The Graphene Council, Tuesday, December 3, 2019
Pipelines constitute a major infrastructure investment frequently carrying materials which in the event of failure can cause significant loss to the owner and serious potential for environmental damage. To fulfil their role pipelines often run long distances either underwater or underground. This physical challenge is often further complicated by the crossing of international borders introducing complex codes and standards of management. Coatings are essential to the protection of pipelines from corrosion and subsequent failure but are themselves subject to degradation by severe abrasion, hydrothermal aging and chemical degradation. These coating systems are typically considered to be passive or active. Passive systems prevent corrosion by blocking key elements of water, oxygen and salts from reaching the pipe surface. Cathodic protection systems (CP) are reactive systems designed to protect pipelines in the event of failure.

Graphene was first produced and identified in 2004 by the group of Andre Geim and Konstantin Novoselev at the University of Manchester, an event which was followed by the Nobel prize for Physics in 2010. One of the remarkable properties of graphene is its impermeability to gases. Graphene manufactured as a single monolayer is time consuming, expensive and difficult to scale. Graphene nanoplatelets (GNPs) offer a cheap and scalable alternative for use in barrier systems. Much research has been carried out on the implementation and use of graphene in coatings including those for pipelines. Direct application of GNP into epoxy has been discussed by Battocchi et al (1) who observed that low level additions of GNP offered improved barrier properties and corrosion mitigation together with improved abrasion resistance. Budd et al(2) applied GNP in laminate structures for flexible risers demonstrating the potential barrier properties of graphene in aggressive conditions. Applied Graphene Materials (AGM) GNPs are manufactured using the company’s patented proprietary “bottom up” process, yielding high specification graphene materials. AGM produce a range of GNP dispersions capable of easy addition into coating systems and have undertaken significant development activity to demonstrate their use in coating systems enabling improved in barrier performance and corrosion resistance.

Corrosion Testing

Current organic coating systems designed for protective coatings applied in harsh environments, such as bridges, are typically comprised of a number of different coating layer, each providing a different set of properties. A basic system usually consists of three layers, which may include a zinc rich primer coat offering sacrificial protection, an intermediate coat and a final topcoat for environmental protection. Typical dry film thicknesses of these coats is around 50 to 150 µm for the primer and intermediate coat and 50 µm for the top coat. Recently it has been demonstrated that GNPs, both as prepared and chemically functionalised, when incorporated into an organic coating system or host matrix, provide via a highly tortuous path which acts to impede the movement of corrosive species towards the metal surface (Okafor et al[3) ) creating a passive corrosion protection mechanism. In support of this, previous work by Choi et al (4) has also shown that very small additions of GNPs decreased water vapour transmission rates indicating a barrier type property, while some authors Aneja et al(5) also report an electrochemical activity provided by graphene within coatings. The introduction of GNPsinto the intermediate coat has recently been demonstrated by AGM(6) to increase significantly the impedance of a protective coating system as measured by EIS when studied in conjunction with Neutral Salt Spray testing (ASTM B117). The intermediate epoxy was formulated as shown below in Table 1.

Three different GNP-containing variants of the control were prepared (D1-D3) using the same initial preparation route as for the epoxy prototype base, by substituting commercially available GNPcontaining dispersion additives (formulation component 10) for epoxy in the final step (formulation component 9). The GNP dispersion additives were effectively treated as masterbatches, and were added in varying amounts according to their graphene content and the final GNP content specified in the end coating (Table 1). The dispersion used in the preparation of D1 and D3 contained a reduced graphene oxide type GNPs (A-GNP10). The dispersions used in the preparation of D2 contained GNPs of a ‘crumpled sheet’ type morphology with a relatively low density and high surface area (A-GNP35). In addition, dispersion D3 based on A-GNP10 contained an active corrosion inhibitor.

Prior to coating application, all substrates were degreased using acetone. Each first coat was applied to grit blasted mild steel CR4 grade panels (Impress North East Ltd.), of dimensions 150 x 100 x 2mm, by means of a gravity fed conventional spray gun. The over coating interval was 3 hours with all panels permitted a final curing period of 7 days at 23°C (+/-2°C). Dry film thickness of the prepared coatings were in the range of 50-60 microns for single coat samples and 150-160 microns for multi coat samples. Full details of the coating systems prepared can be seen in Table 2. All substrates were backed and edged prior to testing.

The panels were placed in a Neutral Salt Spray corrosion chamber, running ISO 9227 for a period of up to 1440 hours. This test method consists of a continuous salt spray mist at a temperature of 35°C. Panels were assessed at 10 day (240 hour intervals) for signs of blistering, corrosion, and corrosion creep in accordance with ISO4628. These assessments were complimented with electrochemical measurements, carried out at the same intervals. All electrochemical measurements were recorded using a Gamry 1000E potentiostat in conjunction with a Gamry ECM8 multiplexer to permit the concurrent testing of up to 8 samples per run. Each individual channel was connected to a Gamry PCT1 paint test cell, specifically designed for the electrochemical testing of coated metal substrates.

Figure 1 shows the progression of impedance modulus for the three coat system samples, measured at 0.1 Hz, over the time period during which the samples were subjected to NSS conditions. Initial impedance values (recorded at t=0) range from the orders of 108 to 1010 Ω.cm2 . The control sample, consisting of a zinc rich primer coat, a layer of commercial equivalent epoxy and polyurethane topcoat, displays the lowest overall impedance values in addition to one of the higher rates of decrease of impedance from the t=0 point. When GNPs are introduced to the intermediate layer, the impedance modulus is increased suggesting that the inclusion of GNPs is acting to increase the barrier performance properties of the system as a whole. The incorporation of A-GNP35 into D2 gave a final system uplift of 5 orders of magnitude above the control. Throughout the testing the D2 formulation showed little change in impedance, compared to the other samples. The achievement of >109 Ohm.cm2 @ 0.1Hz over a period of 1440 hours in neutral salt spray outperformed existing technology in barrier performance equating to a C5 high rating for salt spray performance according to ISO12944-1.

The choice of coating system for pipelines is typically influenced by the geographical region and is often made between thick or thin film build. Critical requirements of coatings in either case are:

• Excellent adhesion

• Low permeability

• Resistance to cathodic disbondment

• High electrical resistance

Thin build coating systems are typically based on Fusion Bonded Epoxy (FBE) either single or double layer being the preferred approach in the North American market. Alternatives might also include high build epoxy or polyurethane. Typically such thin build systems utilise an active CP system to provide additional corrosion protection. Graphene modification as shown by Battochi(1) and by AGM(6) might easily be incorporated into such epoxy or polyurethane systems through the use of AGM’s dispersions. The known electrical conductivity of Graphene might give cause for concern if the incorporation changes the insulating characteristics of the film. The GNP modification demonstrated by AGM is however substantially below the percolation threshold required for conductivity and the net impact on epoxy conductivity is considered negligible (Figure 2).

Thick build coating systems used in other parts of the world are typically 3 layer polyolefin (3LPO and might be polyethylene or polypropylene). AGM has experience in master-batching Graphene into thermoplastics and as such there is no obstacle to the introduction of GNPs into of the main body of the coating. GNP might also be introduced into the adhesive copolymer layer applied to the FBE typically used as a base for the 3LPO coating system.

Tags:  Andre Geim  Applied Graphene Materials  Coatings  Graphene  hydrothermal  Konstantin Novoselev  Nanoplatelets  Pipelines  Pipes  University of Manchester 

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Graphene activates immune cells helping bone regeneration in mice

Posted By Graphene Council, The Graphene Council, Thursday, November 28, 2019
Graphene has been used for many years in the aeronautics and automotive industries and is even used to create new composites. However, it still has a long way to go to offer the consumer the revolutionary applications promised since Andre Geim and Konstantin Novoselov received the Nobel Prize in Physics in 2010. A team of researchers from several Italian universities within the Graphene Flagship Consortium intends to change this and apply it to regenerative medicine therapies.

Publications about the biomedical applications of graphene-based materials have increased in recent years. So says the researcher from Graphene Flagship partner University of Padua (Italy) Lucia Gemma Delogu, who considers that this is due to its "incredible" physicochemical properties, a long list that ranges from its high flexibility and resistance to its good conductivity, both electrical and thermal.

Delogu and her team have worked to take advantage of the material in the field of biomedicine. Their study, published this year in Nanoscale, shows how the immune properties of graphene allow bone tissue to regenerate in mice. This is possible through nano-tools that can activate or deactivate the immune response, an approach that is of great interest for cancer therapies and tissue engineering.

"Graphene-based materials can improve bone regeneration, a complex process that requires interaction between immune and skeletal cells," Delogu explains to Sinc. In the study, the researchers combined a type of graphene oxide with calcium phosphate, a substance capable of activating this regeneration.

"The injection of the graphene-based material into the tibia of mice showed an improvement in the bone mass in the area and in bone formation, suggesting that the combination is capable of activating monocytes to induce osteogenesis," continues the researcher.

How does the body respond to graphene?

Delogu is also the coordinator of the G-Immunomics project, whose objective is to analyse the impact of graphene on the health of living beings, with a view to its possible biomedical applications. G-Immunomics is one of the Partnering Projects of the Graphene Flagship, a European consortium of more than 150 research centres and companies, with a budget of 1,000 million euros and the goal of taking graphene and related materials towards application.

"The use of graphene in biomedicine may revolutionize medical protocols with new theranostic approaches," a concept that merges the terms "therapy" and "diagnosis" in the context of personalized medicine. "If we learn how graphene interacts with our immune system, we will be able to explore much more specific therapies for the treatment of diseases," she says.

The researcher explains that these interactions are complex, so it is still "an image that lacks several colours." By injecting a material, it comes into contact with the immune cells in the blood, which means that studying the impact of graphene on the immune response is "fundamental".

For this reason, Delogu's team is also studying how graphene can stimulate or suppress the immune response. "Our research wants to show a broad picture of the interaction of immune cells in blood with layered materials such as those based on graphene," with the ultimate goal of their possible to apply in biomedicine efficiently but also safely.

Graphene against osteoporosis
Diseases related to bone loss, such as osteoporosis, are a problem for millions of people worldwide. The World Health Organisation estimates that, in Europe alone, 22 million women and 5.5 million men aged 50-84 suffer from osteoporosis.

"Our preclinical research reveals that functionalized graphene may offer a medical opportunity to fight these bone-related diseases," says Delogu. "By promoting bone regeneration, they could also be used to improve the healing of bone wounds and shorten their duration."

Even, she says, "to combat bone loss suffered by astronauts due to lack of gravity". In this área, Delogu is involved in the project WHISKIES recently funded by the European Space Agency.

For all these reasons, she is confident that graphene can a have a future in biomedicine "We are at an early stage, but we hope that the work will open the door to real clinical applications for graphene-based materials," she says. Her dream is to explore the immunological potential of graphene in other fields of regenerative medicine.

Tags:  Andre Geim  Graphene  Healthcare  Konstantin Novoselov  Lucia Gemma Delogu  Medical  University of Padua 

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Eli and Britt Harari Graphene Enterprise Award 2019 Winners Announced

Posted By Graphene Council, The Graphene Council, Tuesday, July 30, 2019
Two new technology businesses share this year’s £70,000 prize for novel applications of graphene and other 2D materials. The two teams, based at The University of Manchester, are addressing key societal challenges on future energy and food security. They are seeking breakthroughs by using 2D materials to produce hydrogen to generate energy, and by designing polymer hydrogels to increase food production.

The Eli and Britt Harari Enterprise Award, in association with Nobel Laureate Sir Andre Geim, is awarded each year to help the implementation of commercially-viable business proposals from students, post-doctoral researchers and recent graduates of The University of Manchester based on developing the commercial prospects of graphene and other 2D materials.

The first prize of £50,000 was awarded to NanoPlexus and its founding team Jae Jong Byun, Dr. Suelen Barg, Francis Moissinac, Wenji Yang and Thomas Moissinac. Jae and Wenji are undertaking their PhD studies in Dr. Suelen Barg’s research group (Nano3D), with Francis starting in September. Thomas is an aerospace engineering graduate from The University of Manchester. The team has worked under the Nano3D lab in formulating their idea into a marketable product.

NanoPlexus will be developing a range of products using their platform technology; the unique nano-material aerogel technology will offer cost-effective renewable hydrogen production with increased material efficiency for a sustainable green-economy.

Jae said: “Recently, there has been an increased footprint and sense of urgency to transition into renewable energy to tackle climate change. Our concept is ideally positioned to support this transition by acting as a stepping-stone for innovative technology growth into conventional energy systems. Our idea of 2D material-based cells supports the forecasted need of renewable energy implementation, as it uses low to zero carbon energy resources.”

Our commitment to the support of entrepreneurship across the University has never been stronger and is a vital part of our approach to the commercialisation of research. Professor Luke Georghiou, Deputy President and Deputy Vice-Chancellor

Francis added: “We are very grateful to Eli and Britt Harari for their generosity and for the support of the University, which will enable us to develop our novel concept that could one day make a meaningful difference; connecting innovation to convention.”

The runner-up, receiving £20,000, was AEH Innovative Hydrogel Ltd, founded by Beenish Siddique. Beenish has recently graduated with a PhD from the School of Materials. Her technology aims to provide an eco-friendly hydrogel to farmers that, not only increases crop production but also has potential to grow crops in infertile and water stressed lands, with minimum use of water and fertilisers.

Beenish said: “Many farmers, especially in third world countries with warmer climates, are interested in my product. I have a solution that offers higher crop yield with less water and fertiliser usage, hence, less greenhouse gases emission and a much cleaner environment.”

The quality of the business proposals presented in this year’s finals was exceptionally high. Professor Luke Georghiou, Deputy President and Deputy Vice-Chancellor of The University of Manchester and one of the judges for this year’s competition said: “Our commitment to the support of entrepreneurship across the University has never been stronger and is a vital part of our approach to the commercialisation of research. The support provided by Eli Harari over the last five years has enabled new and exciting ventures to be developed. It provides our winners the early-stage funding that is so vital to creating a significant business, while also contributing to health and social benefit. With support from our world-leading graphene research facilities I am certain that they are on the path to success.”

The winners will also receive support from groups across the University, including the University’s new state-of-the-art R&D facility, the Graphene Engineering Innovation Centre (GEIC); its leading support infrastructure for entrepreneurs, the Masood Enterprise Centre; as well as wider networks to help the winners take the first steps towards commercialising these early stage ideas.

The award is co-funded by the North American Foundation for The University of Manchester through the support of one of the University’s former physics students, Dr Eli Harari, founder of global flash-memory giant, SanDisk, and his wife, Britt. It recognises the role that high-level, flexible, early-stage financial support can play in the successful development of a business targeting the full commercialisation of a product or technology related to research in graphene and 2D materials.

Tags:  2D materials  AEH Innovative Hydrogel Ltd  Andre Geim  Beenish Siddique  Eli Harari  Graphene  Graphene Engineering Innovation Centre  Jae Jong Byun  Luke Georghiou  NanoPlexus  SanDisk  Suelen Barg  Thomas Moissinac  Wenji Yang 

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Graphene and the Nuclear Decommissioning Authority in the UK

Posted By Graphene Council, The Graphene Council, Friday, April 5, 2019
Updated: Friday, April 5, 2019

Emerging technologies such as graphene are being investigated by the Nuclear Decommissioning Authority (NDA) in the UK for their potential to improve decommissioning of nuclear sites.

The Challenge

To identify how graphene, an emerging technology, could improve delivery of NDA’s mission.

The Solution

Review the properties of graphene including the latest developments and areas for potential deployment.

Technology Review : Graphene – a form of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice with unique chemical and physical properties.

Expected Benefits: Raising awareness of new emerging technology across the NDA Group and supply chain.

The NDA published a report on its findings and research over the period of 2016 - 2018: "Graphene and its use in nuclear decommissioning", produced in collaboration with NSG Environmental, the University of Manchester and the National Physical Laboratory

Highlights:

Graphene’s chemical and physical properties are unique:

- one of the thinnest but also strongest materials

- conducts heat better than all other materials

- conducts electricity

- is optically transparent but so dense that it is impermeable to gases

Developments in graphene-based technology have been rapid in a number of areas, including advanced electronics, water filtration and high-strength materials. NDA identified graphene as an emerging technology that could be useful to improve delivery of its mission.

NDA carried out a technology review to compare the properties and potential uses of graphene against the challenges facing the UK in decommissioning its earliest nuclear sites. The opportunities identified included:

  • Advanced materials: Graphene-doped materials could help to immobilise nuclear wastes.
  • Composites incorporating graphene could be used in the construction of stronger buildings or containers for storing nuclear materials.
  • Cleaning up liquid wastes: Graphene-based materials could absorb or filter radioactive elements, helping to clean up spills or existing radioactive wastes.
  • Sensors: Graphene in sensors could improve the detection of radiation or monitor for the signs of corrosion in containers.
  • Batteries: Graphene could produce smaller, longer-lasting batteries that would enable robots to operate for longer in contaminated facilities.

NDA also assessed the potential limitations in graphene’s use to provide a balanced assessment.

The issues identified included:
- cost
- scale-up
- environmental concerns
- lack of standardization
- knowledge regarding radiation tolerance

The report was shared with technical experts across the NDA group, published online and summarised in the Nuclear Institute’s journal: Nuclear Futures. As the technology moves on from early-stage research, NDA and its businesses are continuing to monitor developments, such as the recently opened Graphene Engineering and Innovation Centre (GEIC), with the aim of supporting graphene-based technologies and accelerating their uptake within the nuclear decommissioning sector.

NDA is progressing further projects investigating the potential of other emerging technologies. Engagement continues with academia and industry to identify innovations that could improve delivery of the mission.

Tags:  Andre Geim  Batteries  Graphene  Graphite  Konstantin Novoselov  Sensors  University of Manchester 

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Graphene Nanomaterials Unlocking New Possibilities

Posted By Terrance Barkan, Friday, March 8, 2019

Since the isolation of graphene in 2004 ( a single plane of sp2 carbon bonded atoms in a hexagonal honeycomb lattice), there has been a significant amount of research and application development work in academic and industrial organizations world-wide. 

Today, graphene is being produced and used in commercial quantities in a wide range of application areas, from  energy storage to construction materials. In fact, more than 40 discreet industries and applications are set to be disrupted by the extraordinary properties of a range of graphene materials.

Although the original definition of graphene is carbon as a single layer of atoms, commercial forms of graphene include; CVD Monolayer, Graphene Nano-platelets (GNPs), Graphene Oxide and various forms of functionalized graphene depending on the the intended application.

 

There are more than 200 companies world-wide that claim to produce graphene materials with new companies entering the sector every day.

The Graphene Council was founded in 2013 to represent the graphene community, including researchers, producers, application developers and end users. Today our community includes more than 20,000 material scientists and R&D professionals world-wide. 

We are actively working to support and advance the commercial adoption of graphene though the development of standards as members of the ISO/ANSI/IEC standards working groups as well as our quality control initiative,  the Verified Graphene Producers program which includes in-person inspections and testing of material at leading laboratories, like the National Physical Laboratory (NPL) in the UK,

The Graphene Council is also a founding Affiliate Member of the Graphene Engineering and Innovation Center (GEIC) at the University of Manchester. The GEIC allows for the rapid prototyping and testing of graphene enhanced products through the use of onsite industrial grade equipment and material characterization tools. 

If you are interested in learning how graphene can unlock new performance gains for your products or if you have new application ideas, contact us. 

Our global team of experts can help you identify the right partners and materials for your objectives. Contact us for more information. 

 

Graphene was first isolated at the 

University of Manchester in 2004 by 

Dr. Andre Geim and Dr. Konstantin Novoselov 

for which they received the 

Nobel Prize in Physics in 2010.

 

Tags:  Andre Geim  graphene  Konstantin Novoselov  Nobel  the graphene council  The Graphene Flagship 

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Graphene Membranes Enable a Novel Approach to Ubiquitous Photodetectors

Posted By Dexter Johnson, IEEE Spectrum, Monday, March 12, 2018

Image: University of Manchester

Back in January, scientists in Andre Geim’s research team at the University of Manchester reported that light could be used to enhance proton transport through graphene.  What this means is the possibility of an entirely new class of photodetectors, which are used in just about everything from high-speed optical communication networks to the remote control for your TV.

Needless to say, an entirely new class of photodetectors—based on proton transport as opposed to all current photodetectors today that are based on electron transport—is a pretty significant development. You add on to this the fact that the photodetectors made from graphene are 100,000 times more responsive than silicon and you have the basis of a transformative technology.

What regular readers of The Graphene Council may have missed earlier this month in an Executive Q&A with Jeffrey Draa, CEO of Grolltex, was that we got some indications in that interview that the technology being developed in Geim’s lab is ramping up for commercial applications.

Draa said in the interview: “…we’re also starting to get some inquiries for an application that actually Dr. Andre Geim at the University of Manchester, who, of course, was the discoverer of graphene was very passionate about. This is one of the very first applications that he thought futuristically would really make the world a better place, and that third application that we're starting to see on the horizon is graphene as a proton exchange membrane in a hydrogen fuel cell.”

Draa in this interview points to the initial applications that were discussed almost four years ago for this graphene-based proton exchange membrane. At the time, Geim had discovered that contrary to the prevailing wisdom that graphene was impermeable to all gas and liquids  it could, in fact, allow protons to pass through. This made scientists immediately conjure up the proton exchange membranes that are central to the functioning of fuel cells.

While there’s no reason to think that these graphene membranes won’t someday make for excellent proton exchange membranes for fuel cells, the problem is that fuel cells are not exactly ubiquitous. However, photodetectors certainly are ubiquitous, making for a much larger potential market for these graphene membranes.

Of course, it’s a pretty big step to make these graphene membranes go from being used for fuel cells to being used in photodetectors. So how did this application switch occur?

The University of Manchester scientists started with monolayer graphene decorated with platinum (Pt) nanoparticles. In operation, photons (light) strike the membrane and excite the electrons in the graphene around the Pt nanoparticles. This makes the electrons in the graphene become highly reactive to protons. This, in turn, induces the electrons to recombine with protons to form hydrogen molecules at the Pt nanoparticles. This process mimics the way in silicon-based photodetectors operate based on electron-hole recombination.

While there are similarities between the semiconductor approach to electron-hole recombination, the photon-proton effect used in this graphene membrane would represent a big departure from the previous approach and nobody is quite sure what the implications might be.

However, it is clear that this graphene membrane that Grolltex is working on with the scientists at Manchester may have a new set of applications that extends far beyond just typical membrane-based technologies.

Tags:  Andre Geim  fuel cells  membranes  photodetectors  University of Manchester 

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New Properties Open Up New Applications for Graphene

Posted By Terrance Barkan, Friday, November 11, 2016

From properties as a superconductor to unexpected membrane separation abilities, graphene continues to surprise

 

When graphene is discovered to have new and sometimes unexpected properties, it quickly adds on potential new applications that it could be used for. 

 

This year we have seen that it actually does become a superconductor, opening up potential as material used in quantum computers. We have also seen graphene surprise even the Nobel Laureate who discovered it by it serving as a membrane for filtering out nuclear waste at nuclear power plants.

 

Graphene’s Potential as a Superconductor Just Got a Clearer

 


 

Illustration: Takashi Takahashi/Tohoku University

 

Graphene’s property as a conductor is unrivalled. The ballistic transport of graphene—the speed at which electrons pass through a material at room temperature—is so fast that it has surpassed what scientists believed were its theoretical limits. It is at the point now where electrons seem to be behaving like photons in graphene. Whenever this amazing property of graphene as a conductor is mentioned, people wonder if it might make for a good superconductor.

 

While there has been some research that has suggested that graphene could be made into a superconductor—a material with zero resistance to the flow of electricity—we now have more conclusive proof that it is indeed the case. 

 

In joint research out of Tohoku University and the University of Tokyo in Japan, scientists there have developed a new method for getting graphene to behave as a superconductor,  and in so doing have eliminated the chance that what they were observing was the transformation of graphene into a semiconductor.

 

Takashi Takahashi, a professor at Tohoku University and leader of the research, explained that they took a number of different approaches to ensure that what they were witnessing was graphene becoming a superconductor. In research published in the journal ACS Nano,  the researchers were first extremely meticulous about how they fabricated the graphene. 

 

They started with high-quality graphene on a silicon carbide crystal, and controlled the number of graphene sheets. This gave them a well-characterized bilayer graphene, into which they stuffed calcium atoms. So precise was the process hat they could actually ascribe a chemical formula to their sample: C6CaC6. This was an important achievement because having a precise count for the number of Li or Ca atoms determines the amount of donated electrons into graphene, which controls the occurrence of superconductivity.

 

The researchers’ measurements confirmed that superconductivity did occur with the graphene. Electrical resistivity dropped rapidly at around 4 K (-269 °C), indicative of an emergence of superconductivity. The measurements further indicated that the bilayer graphene did not create the superconductivity, nor did lithium-intercalated bilayer graphene exhibit superconductivity. This meant that the drop in resistance was due to the electron transfer from the calcium atoms to the graphene sheets.

 

Now that graphene has been made to perform as a superconductor with a clear zero electrical resistivity, it becomes possible to start considering applying graphene into the making of a quantum computer that would use this superconducting graphene as the basis for an integrated circuit.

 

Unfortunately, like most superconducting materials, the temperature at which graphene reaches superconductivity is too low to be practical. Raising that temperature will be the next step in the research. 

 

Graphene Nanoribbons Increase Their Potential

 


Image: Patrick Han

 

Graphene nanoribbons (GNRs) appear to be among the best options for electronics applications because of the each with which it’s possible to engineer a band gap into them. Narrow ones are semiconductors, while wider ones act as conductors. Pretty simple.

 

With improved methods being developed for manufacturing GNRs that are both compatible with current semiconductor manufacturing methods and can be scaled up, the future would appear bright. But there’s not a lot of knowledge of what happens when you start trying to manipulate GNRs into actual electronic devices.

 

Now a team of researchers at Tohoku University's Advanced Institute of Materials Research (AIMR) in Japan is investigating what happens when you interconnect GNRs end to end using molecular assembly to form elbow structures, which are essentially interconnection points.  The researchers believe that this development provides the key to unlocking GNRs’ potential in high-performance and low-power-consumption electronics.

 

“Current molecular assemblies either produce straight GNRs (i.e., without identifiable interconnection points), or randomly interconnected GNRs,” said Dr. Patrick Han, the project leader, in press release. “These growth modes have too many intrinsic unknowns for determining whether electrons travel across graphene interconnection points smoothly,” said Han, who added that, “The key is to design a molecular assembly that produces GNRs that are systematically interconnected with clearly distinguishable interconnection points.”

 

In research published in the journal ACS Nano, the AIMR researchers demonstrated that both the electron and thermal conductivities of two interconnected GNRs should be the same as that of the ends of a single GNR.

 

“The major finding of this work is that interconnected GNRs do not show electronic disruption (e.g., electron localization that increases resistance at the interconnection points),” said Han in the press release. “The electronically smooth interconnection demonstrates that GNR properties (including tailored band gaps, or even spin-aligned zigzag edges) can be connected to other graphene structures. These results show that finding a way to connect defect-free GNRs to desired electrodes may be the key strategy toward achieving high-performance, low-power-consumption electronics.”

 

Graphene Has Special Properties for Cleaning Up Nuclear Waste

 


Image: The University of Manchester

 

The merits of graphene as a separation membrane medium have long been extolled.  The properties that distinguish graphene for these applications are its large surface area, the variability of its pore size and its adhesion properties.

 

These attractive properties have not gone unnoticed by Andre Geim, who, along with Konstantin Novoselov, won the 2010 Nobel Prize in Physics for their discovery and study of graphene. Geim has dedicated a significant amount of his research efforts since then to the use of graphene as a filtering medium in various separation technologies.

 

Now Geim and his colleagues at the University of Manchester have found that graphene filters are effective at cleaning up the nuclear waste produced at nuclear power plants.   This application could make one of the most costly and complicated aspects of nuclear power generation ten times less energy intensive and therefore much more cost effective.

 

In research published in the journal Science, Geim and his colleagues at Manchester experimented to see if the nuclei of deuterium—deuterons—could pass through the two-dimensional (2-D) materials graphene and boron nitride. The existing theories seemed to suggest that the deuterons would pass through easily. But to the surprise of the researchers, not only did the 2-D membranes sieve out the deuterons, but the separation was also accomplished with a high degree of efficiency.

 

“This is really the first membrane shown to distinguish between subatomic particles, all at room temperature,” said Marcelo Lozada-Hidalgo, a post-doctoral researcher at the University of Manchester and first author of the paper, in a press release. “Now that we showed that it is a fully scalable technology, we hope it will quickly find its way to real applications.”

 

Irina Grigorieva, another member of the research team, added: “It is a really simple set up. We hope to see applications of these filters not only in analytical and chemical tracing technologies but also in helping to clean nuclear waste from radioactive tritium.”

Tags:  Andre Geim  ballistic transport  Irina Grigorieva  Konstantin Novoselov  Marcelo Lozada-Hidalgo  University of Manchester 

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