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Corrosion 2020

Posted By Graphene Council, Saturday, February 29, 2020
Applied Graphene Materials are exhibiting at Corrosion 2020 in Houston, Texas on 15-19 March 2020. Please visit our stand number 1254.

At the show AGM will be promoting our Genable® range which delivers outstanding enhancements to anti-corrosion and barrier performance, while providing opportunities to further optimise other coating characteristics.

We will be giving a presentation titled: Improvements in Anti-corrosion Performance through the Integration of Graphene Nano Platelets (GNPs) into Coating Systems for C4/C5 Environments via GNP Tie Coats.

John Willhite and Adrian Potts will be at the show to answer any questions you may have. If you would like to arrange an appointment to visit us you can contact us by e-mail at info@appliedgraphenematerials.com.

Tags:  Adrian Potts  Applied Graphene Materials  Coatings  Corrosion  Graphene  Graphene Nano Platelets  John Willhite 

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Graphene from sugar, a sweet protocol

Posted By Graphene Council, Saturday, February 29, 2020

Scientists from the Centre for Nano and Soft Matter Sciences, Bengaluru, an autonomous institution under the Department of Science & Technology, Government of India have synthesised reduce graphene oxide (rGO) by the combustion of table-sugar.

The group led by Prof. C. N. R. Rao consisting of Dr. P. Chithaiah from CeNS and Prof. G. U. Kulkarni from JNCASR, Bengaluru has developed a rapid and simple route for the synthesis of rGO by the combustion of table-sugar. This method being single-step and reproducible is advantageous compared to the reported protocols used presently. Further, the synthesis doesn’t involve any metal catalysts, expensive reagents, solvents, hazardous chemicals, and, most importantly, it has the ability to produce graphene oxide in large quantities at rapid rates.

Graphene, a one-atom-thick, two-dimensional sheet of sp2 hybridized carbon atoms is known as a wonder material, as it is stronger than diamond, conducts better than copper along with many other interesting properties. However, the production of graphene in large scale has many challenges to address. 

Till date, methods like chemical vapor deposition, arc discharge, aerosol pyrolysis, mechanical exfoliation, solvothermal, hydrothermal synthesis, laser reduction of graphite oxide have been developed to prepare graphene (reduce graphene oxide, rGO).

All these methods either involve hazardous chemicals, high temperatures, and inert atmosphere making them expensive and thus becoming irrelevant for bulk scale applications.

The team believes that the process developed may have a significant impact on various products, including batteries. Their work has been published in the ‘Beilstein Journal of Nanotechnology.’

Tags:  2D materials  C. N. R. Rao  Centre for Nano and Soft Matter Sciences  chemical vapor deposition  G. U. Kulkarni  Graphene  graphene oxide  nanotechnology  P. Chithaiah 

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Oil separation made easier with 2D material membrane

Posted By Graphene Council, Friday, February 28, 2020
University of Manchester researchers have made a leap forward in overcoming one of the biggest problems in membrane technology- membrane fouling.

Membrane-based separations are essential for various processes, such as water filtration and oil and gas separation. The use of graphene and other 2D materials in membrane technology has attracted significant attention due to the tunability of these materials making it possible to filter impurities previously not thought possible.

Fouling is an inevitable event in membrane separation, where blockages occur in the pores of a membrane, stopping the flow and preventing the membrane from functioning normally. Fouling is an especially severe issue for oil separation technology due to how easily the oil droplets stick onto the membrane surface.

Published in Nature Communications, the team based in the Department of Chemical Engineering & Analytical Science, Henry Royce Institute and the National Graphene Institute in collaboration with University College London (UCL), have demonstrated that the exfoliated two-dimensional form of vermiculite, a natural clay mineral, can be used as a fouling resistant coating for oil-water separation.

It is well known that increasing the water wettability and decreasing the oil adhesion on a membrane can reduce membrane fouling due to oil deposition. The scientific community has in the past mainly focused on tuning the surface charge of the membrane by chemical modification to enhance the water wettability and hence reduce fouling. These attempts have succeeded in part, but long-term antifouling properties were yet to be attained.

Now the team at The University of Manchester have found that the wetting properties of vermiculite membranes, prepared by stacking many layers of two-dimensional vermiculite sheets, can be tuned from super-hydrophilic to hydrophobic simply by exchanging the cations present on the surface and between the layers of vermiculite.

Developing antifouling membranes for oil-water separation is a long-sought objective for scientists and technologists, which is evident from the rapid growth in the number of publications in this area, Professor Rahul Raveendran Nair.

Further, the team also demonstrated how to exploit this unusual property for reducing the membrane fouling during oil-water filtration by using superhydrophilic lithium exchanged vermiculite (lithium vermiculite) as a coating layer for commercial microfiltration membranes.

Dr Kun Huang, the lead author of the paper said: “Lithium vermiculite membranes not only provide superhydrophilicity but also repel oil droplets during filtration due to their underwater superoleophobic property. The under-water oil adhesion on vermiculite coated microfiltration membranes was more than 40 times lower than the noncoated membrane.”

The demonstrated oil-water separation is just one example of the use of super-hydrophilic antifouling membranes. Their application could be expanded to other areas such as developing self-cleaning surfaces, and antifouling filters for biofiltration.

Professor Rahul Raveendran Nair said: “Developing antifouling membranes for oil-water separation is a long-sought objective for scientists and technologists, which is evident from the rapid growth in the number of publications in this area. We believe our work provides a major advance in the fundamental understanding of wetting properties of solids down to the molecular level and is a notable milestone in the development of robust fouling resistant membrane technologies.”

The work was done in collaboration with scientists from the Department of Physics & Astronomy at UCL to probe the mechanism of the unusual water wetting transition in the vermiculite membrane upon ion exchange.

Patrick Rowe, from UCL said: “Our study shows how the atomic-scale details of the interaction between water molecules, surfaces and ions are important for understanding the surface properties of solids. The high water affinity and hence lower oil droplet interaction of the lithium vermiculite is due to the unique arrangement of water molecules on the surface of lithium vermiculite.”

Dr. Christie Cherian, who co-authored the paper said, “The presence of ions in the vermiculite membrane helped to pin the water molecules firmly on the surface even when the membrane is exposed to oil for a prolonged period of time, a property unique to the vermiculite coated membrane, shows promise for using it as a long-term antifouling coating.

Tags:  2D materials  Christie Cherian  Graphene  Henry Royce Institute  Kun Huang  Patrick Rowe  Rahul Raveendran Nair  University College London  University of Manchester 

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Study puts spin into quantum technologies

Posted By Graphene Council, Thursday, February 27, 2020

A team of international scientists investigating how to control the spin of atom-like impurities in 2D materials have observed the dependence of the atom's energy on an external magnetic field for the first time.

The results of the study, published in Nature Materials, will be of interest to both academic and industry research groups working on the development of future quantum applications, the researchers say.


Researchers led by Prof Vladimir Dyakonov at the University of Würzburg in collaboration with scientists from the University of Technology Sydney (UTS), the Kazan Federal University and the Universidade Federal de Minas Gerais, demonstrated the ability to control the spin of atom-like impurities in 2D material hexagonal boron-nitride. By combining laser and microwave excitation the researchers were able to change the spin states, for example "up" to "down", of atom-like impurities hosted in the material and show the dependence of their energy on an external magnetic field.

This is the first time that the phenomenon has been observed in a material that is made of a single sheet of atoms like graphene. The researchers say that this newly demonstrated quantum spin-optical properties, combined with the ease of integrating with other 2D materials and devices, establishes hexagonal boron-nitride as an intriguing candidate for advanced quantum technology hardware.

"2D atomic crystals are currently some of the most studied materials in condensed matter physics and materials science," says UTS physicist Dr Mehran Kianinia, a co-author of the study.

"Their physics is intriguing from a fundamental point of view, but beyond that, we can think of stacking different 2D crystals to create completely new materials, heterostructures and devices with specific designer properties," he says.

UTS researcher, Dr Carlo Bradac, a senior co-author of the study says that in addition to adding another unique property, to an already impressive range of properties for a 2D material, the discovery has enormous potential for the field of quantum sensing.

"What really excites me is the potential [in the context of quantum sensing]. These spins are sensitive to their immediate surroundings. Unlike 3D solids, where the atom-like system can be as far as a few nanometres from the object to sense, here the controllable spin is right at the surface. Our hope is to use these individual spins as tiny sensors and map, with unprecedented spatial resolution, variations in temperature, as well as magnetic and electric fields onto variations in spin" Dr Bradac says.

"Imagine, for instance, being able to measure minuscule magnetic fields with sensors as small as single atoms. The possibilities are far reaching and range from nuclear magnetic resonance spectroscopy for nanoscale medical diagnostic and material chemistry to GPS-free navigation using the Earth's magnetic field," he says.

However quantum-based nanoscale magnetometry is "just one area where controlling single spins in solids is useful" says senior author of the study UTS Professor Igor Aharonovich.

"Beyond quantum sensing, many quantum computing and quantum communication applications rely on our ability to control the spin-state--zero, one and anything in between--of single atom-like systems in solid host materials. This allows us to encode, store and transfer information in the form of quantum bits or qubits," he says.

Amongst many others, this research highlights how scientists are quickly becoming masters in the craft of manipulating objects in the quantum regime. In fact, achievements like Lockheed Martin's Black Ice project and Google's quantum supremacy are proof that we are striding away from mere proof-of-concept experiments towards real world, quantum-enabled solutions to practical problems.

Tags:  2D materials  Graphene  Hexagonal boron nitride  Kazan Federal University  Nature Materials  Universidade Federal de Minas Gerais  University of Technology Sydney  University of Wurzburg  Vladimir Dyakonov 

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Gratomic Provides Update to Shareholders

Posted By Graphene Council, Tuesday, February 25, 2020
Gratomic Inc is pleased to provide the following update to shareholders on general operations and the issuance of mining license ML215.

Mining License Update


On the 24th of January the Company's Co-CEO, Arnoldus Brand met with the Ministry of Mines and Energy in Namibia to satisfy a request that came from the special committee that is in charge of recommending the mining license request to the Minister of Mines and Energy, to provide an update on mine development and to fulfill certain criteria required for the approval of the mining license.

The Company is happy to report that it fulfilled 100% of the required criteria during the meeting and was requested to amend the current Environmental Impact Assessment and Environmental Management Plan over EPL 3895 to include ML 215.

After meeting with the members of the special committee, the Company immediately engaged Risk-Based Solutions (RBS) CC, Consulting Arm of Foresight Group Namibia (FGN) (Pty) Ltd, to start amending the EIA and EMP to include ML215. The final submission of the amended EIA and EMP was done on the 17th of February 2020. Through this submission Gratomic has now fulfilled all requirements to satisfy the committee's requests and is now waiting to hear back from the Ministry of Mines and Energy with respect to the granting of mining licence ML215.

We would like to thank the Ministry for their co-operation and hard work to help Gratomic advance towards a mining company from a junior exploration company.

Operations Update

The Chinese manufacturing facility that is supplying the last pieces of equipment that make up the greater part of the drying circuit for the Aukam mine graphite processing plant has experienced significant delays due to the impact of the Coronavirus and has been unable to ship the equipment. The Company has been waiting for correspondence from the manufacturer on the platform designs that are required to be poured at the same time as the shipment leaves China to provide a sufficient curing period for the concrete platforms. The minimum shipping time from China to Namibia is 39 days once the equipment leaves port. We foresee further delays at both the port of China and the port of Walvis Bay given strict quarantine restrictions at both ports currently.

On the 19th of February the Company received feed-back from the manufacturer on the platform designs and confirmation that some of the staff have returned back to the factory and it is now able to proceed with shipping of the remaining equipment.

The List of Equipment from China includes the following:

Cyclone Cluster

10 m Electrical Dryer

Thickener

600 mm conveyor belt

Filter press

Slurry pumps and lines

The equipment was specifically designed and built to accommodate mass balance pull and the treatment of Aukam Graphite based on the results of our pilot testing programs.

The remainder of the equipment has already been set up on site and what remains is the arrival of this equipment to fully complete the 20,000 tonnes per year operating capacity of the processing facility.

We appreciate the patience of our shareholders during this delay.

We further sympathize with our Chinese vendors as they have been going through a difficult time.

Management Update

In an effort to reduce the Company's expenditures, the majority of Namibian staff and management has agreed to go to 50% remuneration as per SECTION 12 (6) OF THE NAMIBIAN LABOUR ACT NO 11 OF 2007 until the granting of ML215. The Canadian management team has lead by example by doing the same in an effort to preserve capital for operations.

The efforts by the Namibian team to agree to such conditions is extraordinary and shows their commitment to the success of the business.

We thank each and every one of our devoted and hard-working employees for their commitment towards the success of Gratomic as a company.

Financing Update

Gratomic further pushes to conclude its current financing as the Company moves towards fully commercializing its assets.

To date the Company has raised CAD $626,000 of up to a CAD $2.5 million-dollar issuance.

Management has excelled beyond their calling to do as much as they can to further operations along and will continue to work relentlessly to earn success.

TODA Notes Update


Further to the press release of October 17, 2019, where Gratomic announced the Supply Agreement with TODAQ Holdings ("TODAQ") to supply TODAQ with an aggregate of USD $25,000,000 of graphite, payable in TODA Notes ("TDN"), and the subsequent press release on December 20, 2019 where Gratomic received its first of two purchase orders from TODAQ, Gratomic is pleased to provide an update on the current status of TDN trading. TDN has been trading on BitForex, a digital asset exchange, with a 30-day average price and volume of approximately USD $0.24 and USD $950,000, respectively. TDN first started trading on Bitforex on November 1, 2019 at a price of USD $0.10 and a volume of USD $300,000. To follow TDN, please click the following link: https://www.bitforex.com/en/spot/tdn_btc. No TDN will be issued to the Company until the equipment arrives from China and the processing plant is in production.

Arno Brand, Co-CEO, stated: "These have been trying times for the Company as it progresses its efforts to evolve from a junior exploration company to a mining company. The achievements of those that have sacrificed their time in making it a reality will not go unnoticed. The Company is still in a very strong position as it has built its operations without having to fall on the assistance of an abusive debt transaction that will impede its profitability and damage shareholder value going forward. I am proud of our team for their patience and hard work as we wait for our mining license. I would further like to thank all the shareholders for their continued support."

Risk Factors

No mineral resources, let alone mineral reserves demonstrating economic viability and technical feasibility, have been delineated on the Aukam Property. The Company is not in a position to demonstrate or disclose any capital and/or operating costs that may be associated with satisfying the terms of the TODAQ Supply Agreement.

Gratomic wishes to emphasize that Supply Agreement is conditional on Gratomic being able to bring the Aukam project into a production phase, and for any graphite being produced to meet certain technical and mineralization requirements.

Gratomic continues to move its business towards production and as part of its business plan, expects to obtain a National Instrument 43-101 Standards of Disclosure for Mineral Projects technical report to help it ascertain the economics of Aukam. Presently the Company uses its existing pilot processing facility to produce certain amounts of graphite concentrate from accumulated surface graphite.

The Company advises that it has not based its production decision on even the existence of mineral resources let alone on a feasibility study of mineral reserves, demonstrating economic and technical viability, and, as a result, there may be an increased uncertainty of achieving any particular level of recovery of minerals or the cost of such recovery, including increased risks associated with developing a commercially mineable deposit.

The Supply Agreement provides that if Gratomic is unable to deliver graphite in accordance with the orders from Todaq, Todaq has the right to refuse to take any subsequent attempt to fulfill the order, terminate the agreement immediately, obtain substitute product from another supplier and recover from the Company any costs and expenses incurred in obtaining such substitute product or suing for damages under the contract.

Historically, such projects have a much higher risk of economic and technical failure. There is no guarantee that production will begin as anticipated or at all or that anticipated production costs will be achieved.

Failure to commence production would have a material adverse impact on the Company's ability to generate revenue and cash flow to fund operations. Failure to achieve the anticipated production costs would have a material adverse impact on the Company's cash flow and future profitability.

Steve Gray, P.Geo. has reviewed and approved the scientific and technical information in this press release and is Gratomic's "Qualified Person" as defined by National Instrument 43-101 - Standards of Disclosure for Mineral Projects.

Tags:  Arnoldus Brand  Graphene  Graphite  Gratomic 

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POSITION AVAILABLE: Conductive Ink Formulation Scientist

Posted By Graphene Council, Tuesday, February 25, 2020

Nanotech Energy is developing cutting-edge energy storage solutions for the electric and portable electronics markets. This technology is based on the wonder material graphene that is established as the thinnest, strongest and most conductive material. Our mission at Nanotech Energy is to harness the power of graphene into world-changing battery solutions. We also take advantage of the outstanding structural, mechanical and electronic properties of graphene to develop conductive inks and adhesives as well as electromagnetic interference shielding materials with unparalleled performance. Nanotech Energy seeks talented scientists and engineers to join the expanding development and production teams. Choosing where to start and grow your career has a major impact on your professional and personal life. Nanotech Energy is home for cutting-edge graphene and nanomaterials technology and our scientists develop solutions that impact our community and the world. We offer you a chance to join a high-growth company at an early stage and shape the direction of our culture.

Position Summary :

Nanotech Energy, Inc. is seeking a talentedInk Formulation Scientist to join our expanding team located in Northern California. As a leading company in the manufacture of graphene oxide, silver nanoparticles and nanowires, we plan to offer our customers a full spectrum of conductive inks for a wide range of applications.

The successful candidate will work with our chemistry team and analytical scientists to develop conductive inks for the growing markets of printed electronics and smart packaging.You will use your knowledge in conductive ink formulations to develop, validate and implement inkjet, aerosol and screen printing inks. This job requires a strong hands-on experience in a variety of printing processes and ink formulations and the ability to work independently with little supervisions, yet also be an integral team member. As our residential expert in conductive inks, you will coordinate ink development with cross-functional teams to meet our engineering and customer needs. You will also be responsible for facilitating the transition of our inks from development to manufacturing. Nanotech Energy is made up of amazing individuals but it’s only through teamwork that we achieve greatness. At Nanotech Energy, you will be given the opportunity to participate and join in the growth stage of a startup company and contribute at all levels to make an impact.

Job Type: Full-time

Job level: Senior level 

Responsibilities and Duties

• Lead technical and quality needs for our conductive inks projects to address immediate and strategic problems of the company.
• Contribute to the continuous improvement of processes and capabilities in the company.
• Participate in the design and development ofa new laboratory for inkjet, aerosol and screen printing applications. 
• Develop or improve existing products and processes to prepare dispersions and inks and help to implement in production. 
• Synthesize and characterize new products, components, and formulations. 
• Assist in collecting data and writing of patent inventions associated with the development of new products. 
• Apply knowledge to provide customer support and troubleshooting in the application of commercial products.
• Assist our engineers and plant production personnel in scaling up the technology from bench to manufacturing.
• Review and write standard operating procedures for analytical development.
• Conduct experiments to test the long-term stability of our inks. Analyze results of experiments and trials and write reports. 
• Assist in the supervision of less experienced chemists and technicians in the team. Provide other support as needed to help maintain an efficientdevelopment lab.
• Communicate ideas and results internally across multiple teams. 

Education and Qualifications

• Bachelor degree in chemistry, materials science, chemical engineering or related field. PhD degree with relevant experience is also acceptable. 
• Experience in the preparation, processing and characterization of conductive inks for printed and flexible electronics. 
• Knowledge of fluid dynamics, rheology, and fluid development is required. 
• Demonstrated history of solving problems with a chemical and analytical approach.
• Strong background in colloidal and surface chemistry and surface treatment through material design, synthesis, and characterization. 
• Experience with the development of transparent conducting electrodes with different surface properties is highly desirable. 
• Examples of instrumentation / techniques: Viscometry, goniometry (with tensiometry), DLS, zeta potential, SEM, TEM
• Knowledge of nanocolloidal system stability; nanoparticle synthesis experience is a plus 
• Scale up experience with nanocolloidal systems
• Experience with at least one printing process is required.
• Experience with nanomaterial surface coatings for added functions is a plus. 
• 3-5 years of industry experience (less for candidates with advanced degrees).

Professional Skills

• Ability to respond to multiple priorities simultaneously; ability to coordinate team and projects to meet the company needs and deadlines. 
• Strong project management skills.
• Skilled in troubleshooting and analytical thinking with an interest in solving complex problems. 
• Ability to deal with a variety of abstract and concrete variables and to conduct studies using the scientific method
• Demonstrated understanding of analytical chemistry and materials science, especially in rheology, polymer, and thermal analysis. 
• Demonstrated ability to communicate effectively in both verbal and written formats; ability to work effectively with team members and management. 
• Competency level should allow the employee to author internal reports, reports to customers, or articles for ink industry publications.
• Experience in 3D printing and thermal inkjet is a plus. 

Work authorization / location:
• United States (Required)

Contact
Scott Jacobson
Director of Business Development
scottjacobson@nanotechenergy.com

Tags:  Battery  Energy Storage  Graphene  nanomaterials  Nanotech Energy  Scott Jacobson 

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New graphene-based metasurface capable of independent amplitude and phase control of light

Posted By Graphene Council, Tuesday, February 25, 2020
Researchers described a new strategy of designing metamolecules that incorporates two independently controllable subwavelength meta-atoms. This two-parametric control of the metamolecule secures the complete control of both amplitude and the phase of light.

A KAIST research team in collaboration with the University of Wisconsin-Madison theoretically suggested a graphene-based active metasurface capable of independent amplitude and phase control of mid-infrared light. This research gives a new insight into modulating the mid-infrared wavefront with high resolution by solving the problem of the independent control of light amplitude and phase, which has remained a long-standing challenge.

Light modulation technology is essential for developing future optical devices such as holography, high-resolution imaging, and optical communication systems. Liquid crystals and a microelectromechanical system (MEMS) have previously been utilized to modulate light. However, both methods suffer from significantly limited driving speeds and unit pixel sizes larger than the diffraction limit, which consequently prevent their integration into photonic systems.

The metasurface platform is considered a strong candidate for the next generation of light modulation technology. Metasurfaces have optical properties that natural materials cannot have, and can overcome the limitations of conventional optical systems, such as forming a high-resolution image beyond the diffraction limit. In particular, the active metasurface is regarded as a technology with a wide range of applications due to its tunable optical characteristics with an electrical signal.

However, the previous active metasurfaces suffered from the inevitable correlation between light amplitude control and phase control. This problem is caused by the modulation mechanism of conventional metasurfaces. Conventional metasurfaces have been designed such that a metaatom only has one resonance condition, but a single resonant design inherently lacks the degrees of freedom to independently control the amplitude and phase of light.

The research team made a metaunit by combining two independently controllable metaatoms, dramatically improving the modulation range of active metasurfaces. The proposed metasurface can control the amplitude and phase of the mid-infrared light independently with a resolution beyond the diffraction limit, thus allowing complete control of the optical wavefront.

The research team theoretically confirmed the performance of the proposed active metasurface and the possibility of wavefront shaping using this design method. Furthermore, they developed an analytical method that can approximate the optical properties of metasurfaces without complex electromagnetic simulations. This analytical platform proposes a more intuitive and comprehensively applicable metasurface design guideline.

The proposed technology is expected to enable accurate wavefront shaping with a much higher spatial resolution than existing wavefront shaping technologies, which will be applied to active optical systems such as mid-infrared holography, high-speed beam steering devices that can be applied for LiDAR, and variable focus infrared lenses.

Professor Min Seok Jang commented, "This study showed the independent control amplitude and phase of light, which has been a long-standing quest in light modulator technology. The development of optical devices using complex wavefront control is expected to become more active in the future."

PhD candidate Sangjun Han and Dr. Seyoon Kim of the University of Wisconsin-Madison are the co-first authors of the research, which was published and selected as the front cover of the January 28 edition of ACS Nano titled "Complete complex amplitude modulation with electronically tunable graphene plasmonic metamolecules".

Tags:  Graphene  KAIST  Min Seok Jang  photonics  plasmonics  Sangjun Han  Seyoon Kim 

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MITO Material Solutions To Present at Industry Events and Conferences

Posted By Graphene Council, Monday, February 24, 2020
MITO Materials, creator of hybrid polymer modifiers that increase the durability, flexibility, and performance of polymer composites, is announcing that the Company will take part three different industry conferences and events this Spring.

Since participating in The Heritage Group accelerator powered by Techstars in Indianapolis, IN, MITO Materials has seen a significant increase in customer on boarding for product integration into various fiber-reinforced thermoset and thermoplastic components as well as graphene-enhanced coatings. Performance data from these customers indicate that MITO’s products could extend the limitations and improve recyclability of materials used in high performance applications.

Caio Lo Sardo, Head of Business Development, says, “We are committed to engaging with customers pushing the boundaries with their current offerings to offer a better tomorrow, together.Our product offerings will further enable formulators and manufacturers to make their fiber-reinforced thermosets and thermoplastics a more viable, higher performing option.

MITO Materials will take part in six leading international industry events:

• JEC World 2020, based in Paris, France (3-5 March 2020)
• Open Minds (19-21 March 2020)
• The American Coatings Show, based in Indianapolis (30 March – 02 April 2020)
• Bicentennial Sponsored Conference: Beyond Boundaries: Indiana Academies Symposium (3-4 April 2020)
• World Adhesives Conference (20-22 April 2020)
• SAMPE 2020, based in Seattle (4-7 May 2020), Dr. Bhishma Sedai will be presenting a technology paper at this event.

Tags:  Caio Lo Sardo  coatings  Graphene  MITO Material Solutions  Plastics  Polymer 

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Graphene Gives Aluminum-Based Explosives More Bang for the Buck

Posted By Graphene Council, Monday, February 24, 2020
Researchers from the U.S. Army have discovered a new way to get more energy out of energetic materials containing aluminum: by coating them with graphene oxide.

This discovery coincides with the one of the Army’s modernization priorities: Long Range Precision Fires. The new fining could lead to more energetic metal powders as propellant/explosive ingredients in Army munitions.

Lauded as a miracle material, graphene is considered the strongest and lightest material in the world. It’s also the most conductive and transparent, and the most expensive to produce. Its applications are many, extending to electronics by enabling touchscreen laptops via light-emitting diode and organic light-emitting diode LCDs and OLED displays. But oxidizing graphite makes graphene oxide (GO) much less expensive to make.

Although GO is a popular two-dimensional material that has attracted intense interest across numerous disciplines and materials applications, this discovery exploits GO as an effective light-weight additive for practical energetic applications using micron-size aluminum powders (uAl)—i.e., aluminum particles one millionth of a meter in diameter. This new work signals the Army beginning to develop better metal propellant/explosive ingredients to protect more lives for the Army warfighters.

"Aluminum (Al) can theoretically release a large quantity of heat (as much as 31 kilojoules per gram) and is relatively cheap due to its natural abundance,” says Chi-Chin Wu of the Army Research Lab. “µAl powders have been widely used in energetic applications.

“However, it is difficult to ignite them using an optical flash lamp due to its poor light absorption,” Wu continues. “To improve its light absorption during ignition, it is often mixed with heavy metallic oxides which decrease the energetic performance.”

Nanometer-sized Al powders (i.e., one billionth of a meter in diameter) can be ignited more easily by a wide-area optical flash lamp , and they release heat much faster than can be achieved using conventional single-point methods such as hotwire ignition. Unfortunately, nanometer-sized Al powders are costly. The team did, however, demonstrate the value of uAl/GO composites as potential propellant/explosive ingredients. It showed that GO lets of uAl via an optical flash lamp, releasing more energy at a faster rate—thus significantly improving the energetic performance of µAl beyond that of the more expensive nanometer-sized Al powder. The team also discovered that the ignition and combustion of µAl powders can be controlled by varying the GO content to get the desired energy output.

Images showing the structure of the µAl/GO composite particles were obtained by high resolution transmission electron (TEM) microscopy. “It is exciting to see through advanced microscopy how a simple mechanical mixing process can wrap µAl particles in a GO sheet,” says Wu.

The researchers also discovered that GO increased the amount of µAl reacting in the microsecond timescale—a regime analogous to the release of explosive energy during a detonation.

Upon initiation of the uAl/GO composite with a pulsed laser using a technique called laser-induced air shock from energetic materials (LASEM), the exothermic reactions of the µAl/GO accelerated the resulting laser-induced shock velocity beyond that of pure µAl or pure GO. So µAl/GO composite can increase the power of military explosives, as well as enhance the combustion and blast effects. This could, therefore , lead to longer range and/or more lethal weapons.

Tags:  Army Research Lab  Chi-Chin Wu  coatings  composites  Graphene  graphene oxide 

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Does graphene cause or prevent the corrosion of copper? New study finally settles the debate

Posted By Graphene Council, Saturday, February 22, 2020
Copper has been essential to human technology since its early days--it was even used to make tools and weapons in ancient times. It is widely used even today, especially in electronic devices that require wiring. But, a challenge with using copper is that its surface oxidizes over time, even under ambient conditions, ultimately leading to its corrosion. And thus, finding a long-term method to protect the exposed surfaces of copper is a valuable goal. One common way of protecting metal surfaces is by coating them with anti-corrosive substances. Graphene is studied extensively as a candidate for anti-corrosive coating, as it serves as a barrier to gas molecules. But, despite these properties, graphene sheets are seen to protect copper from corrosion only over short periods (less than 24 hours). In fact, surprisingly, after this initial period, graphene appears to increase the rate of copper corrosion, which is completely in contrast to its anti-corrosive nature.

To shed light on the peculiar nature of graphene seen in copper, a research team from Chung-Ang University, Korea, led by Prof Hyungbin Son, studied graphene islands on a copper substrate to analyze the patterns of its corrosion. Prof Son explains, "Graphene is known to be mechanically very strong and impermeable to all gases, including hydrogen. Following studies claiming that the corrosion of copper substrates was accelerated under graphene through various defects, these properties have attracted great attention as an oxidation barrier for metals and have been controversial for over a decade. However, they have not been qualitatively investigated over longer time scales. Thus, we were motivated to study the role of graphene as a corrosion-resistant film at the graphene-copper interface." Prof Son and his team used Raman spectroscopy, scanning electron microscopy, and white light interferometry to observe the trends in copper corrosion for 30 days.

At first, the team detected corrosion developing at the edges, spreading the oxidized form of copper, copper oxide (Cu2O), at various defects such as edges, grain boundaries, and missing atoms. This resulted in the splitting of water vapor, supplying oxygen for the oxidation process, until the entire barrier seemed to be rendered useless and copper was fully corroded underneath. Owing to graphene's effect on ambient water vapor, the protected portion of the copper substrate was more corroded than the unprotected portion. Over time, the formation of Cu2O underneath the graphene sheet dispersed the strain and caused p-doping in graphene--creating a hybrid-like structure. But, after 13 days of exposure to ambient conditions, the team discovered something new. They observed that that the corrosion had significantly slowed down where a new hybrid of graphene and Cu2O layer had formed. Meanwhile, the unprotected copper continued to corrode at a consistent rate, until it had penetrated far deeper than the corrosion under the graphene shield.

These findings show that graphene, in fact, protects copper from deep, penetrating oxidation, unlike what previous studies had concluded. Prof Son explained, "We observed that over a longer time scale (more than 1 year), the graphene-Cu2O hybrid structure became a protective layer against oxidation. The area beyond the graphene was heavily oxidized with CuO, with a depth of ?270 nm."

This study has finally managed to settle the debate on whether graphene can be used to protect copper against oxidation. Prof Son concludes, "For nearly a decade, graphene's anti-corrosive properties have been controversial, with many studies suggesting that graphene accelerates the oxidation of copper (resulting in its corrosion). We have shown for the first time that the graphene-Cu2O hybrid structure, which forms over a long period, significantly slows down the oxidation of copper in the long term, as compared to bare copper."

Only time will reveal more about further applications of graphene as an anti-corrosive material. But one thing is certain--this research has potentially taken down several barriers in using graphene to extend the life of copper.

Tags:  Chung-Ang University  coatings  Corrosion  Graphene  graphene oxide  Hyungbin Son 

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