Nano News: 03/17/15

Constructing integrated graphene-based artificial nacre

Over billions of years, intricately structured, high-performance natural materials, such as nacre (also known as mother of pearl), have evolved. Nacre has several properties that have been a source of inspiration for biomimetic materials: (a) a “brick and mortar” layered architecture alternatively packed with 95 vol % of two-dimensional (2D) aragonite calcium carbonate platelets, and 5 vol % of one-dimensional (1D) nanofibrillar chitin and protein, and (b) different interface interactions between inorganic platelets and organic protein. In fact, the extraordinary properties of natural nacre are attributed to the synergistic toughening effects from the different building blocks and interface interactions, Although research on artificial nacre first startedmore than 20 years ago, integrated graphene-based artificial nacre is still in its early stages. Work in this area would be greatly enhanced by the synergistic effects of designing interface interactions and combining different building blocks.

Integrated graphene-based artificial nacre: (a) Natural nacre with a typical micro/nanoscale hierarchical structure supplies the concept for constructing high-performance bioinspired materials. Graphene oxide (GO), with its outstanding physical properties, is one of the best candidates for fabricating bioinspired layered materials. Their many functional surface groups enable interface designs that improve the interfacial strength in the resultant bioinspired composites. Bottom left: The synergistic interfacial interaction is one important approach for constructing integrated graphene-based artificial nacre. Several typical interfacial interactions include hydrogen bonding, ionic bonding, π-π interactions, branched polymers, linear molecules and polymers, and three-dimensional (3D) thermosetting resin networks. Bottom right: The use of synergistic building blocks is another way to construct integrated artificial nacre. The other building blocks could be two 2D nanosheets, such as molybdenum disulfide (MoS2) and tungsten disulfide (WS2), or 1D nanofibers, such as carbon nanotubes (CNT) and nanofibrillar cellulose (NFC). We expect that a breakthrough in graphene-based artificial nacre will be developed through a combination of the synergistic effects of interfacial interactions and building blocks. (© ACS) In new research, reported in a article ("Learning from Nature: Constructing Integrated Graphene-Based Artificial Nacre"), scientists from the Key Laboratory of Bio-inspired Smart Interfacial Science and Technolog in Beijing, have demonstrated an integrated graphene-based artificial nacre with isotropic mechanical and electrical properties due to graphene's intrinsic 2D structure, which is superior to nanofiber-reinforced composites. The researchers anticipate near-term breakthroughs in graphene-based artificial nacre for the development of promising applications in many fields, such as aerospace, flexible supercapacitor electrodes, artificial muscles, and tissue engineering. Integrated graphene-based artificial nacre may also be a potential platformfor the design and construction of robust intelligent devices, such as actuators, artificial muscles, and sensors.

Cage-opening fullerene provide fluorescent graphene quantum dots

New work by an international research team has demonstrated the simultaneous oxidation and cage-opening of fullerene C60 to provide graphene quantum dots. Reporting their findings in ("Synthesis of Strongly Fluorescent Graphene Quantum Dots by Cage-Opening Buckminsterfullerene"), the team synthesized graphene quantum dots (QDs) by treating fullerene C60 with a mixture of concentrated sulfuric acid, sodium nitrate, and potassium permanganate. Lund

Treatment of fullerene C60 with a mixture of strong acid and chemical oxidant induced the oxidation, cage-opening, and fragmentation processes of fullerene C60. (© ACS) Detailed characterization including LDI-TOF MS, TEM, AFM, STM, XPS, DLS, FT-IR, and Raman spectroscopy analyses revealed the formation of aggregated small fragments consisting of carbon, oxygen, and hydrogen elements, which favored the production of graphene QDs. More importantly, the graphene QDs exhibited strong luminescence properties when excited at 340 nm. The highly oxygenated graphene QDs showcased their broad prospects for modifications through successful functionalization reactions. The luminescence properties varied according to the types of chemical treatments, whereby hydroxylamine-functionalized graphene QDs showed a blue-shift of the emission maximum, while hydrazine-reduced graphene QDs showed a red-shift of the emission maximum. All in all, the simplicity of this method in producing graphene QDs shows potential for further development for integration into practical devices or applications including optoelectronics and biological labeling.

API and NINT to keynote 2015 Nanotechnology for Renewable Nanomaterials conference

TAPPI announced that Dr. Theodora Retsina, CEO of American Process, Inc. (API) and Dr. Maria D’lorio, Executive Director of the National Institute for Nanotechnology (NINT) and Professor of Physics and Assistant Vice President of Research at the University of Alberta, will be keynote speakers at the 2015 International Conference on Nanotechnology for Renewable Nanomaterials, in Atlanta, Georgia, June 22-25. “We’re very excited to have these distinguished women speak at this year’s conference,” said Sean Ireland, manager of new technologies at Verso Corporation and co-chair of the 2015 conference. “Their knowledge and success in the field is sure to provide insight and information for all attendees.” Dr. Retsina received a BSc and PhD in Chemical Engineering from Imperial College, University of London and is a licensed professional engineer in the United States. Her career began at Parsons & Whittemore, where she held positions as project engineer, project manager and process manager in various international construction projects. In 1995, she founded API – a company that focuses on value enhancement of the biomass industries through process integration, biorefinery technology applications and value engineering. Dr. D'Iorio obtained a Ph.D. in solid state physics and worked as a post-doctoral fellow at the IBM Zurich Research Laboratory in Switzerland before returning to Canada to work at the National Research Council. After enjoying eighteen years as a researcher in organic and inorganic nano-electronics , Dr. D’Iorio became Director and subsequently Director-General of NRC’s Institute for Microstructural Sciences (NRC-IMS). She has championed a number of large collaborative programs, in partnership with government departments, industry and academia to accelerate photonics and nanotechnology deployment in the ICT, Construction, and Energy sectors. Dr. D’Iorio has served as the President of the Academy of Science of the Royal Society of Canada and as President of the Canadian Association of Physicists. The International Conference on Nanotechnology for Renewable Materials is the only event that explores how nanotechnology can transform biomaterials into high-value products that expand and transcend traditional forest products portfolios. Bringing together leading researchers, industry experts, government representatives and other stakeholders from around the world, this event promises a unique, multi-disciplinary look at the rewards of using nanotechnology – from the forest to marketed products. Whether your focus is new product development, academic study or supplier research, this conference will provide the big picture for unlocking value from this tiny technology. Join more than 200 delegates from around the world this June in Atlanta. Learn more about TAPPI’s Nanotechnology Division where members support the growth of this emerging technology through various committees and activities. About TAPPI TAPPI is the leading association for the worldwide pulp, paper, packaging, tissue and converting industries and publisher of Paper360°, Tissue360° and TAPPI Journal. Through information exchange, events, trusted content and networking opportunities, TAPPI helps members elevate their performance by providing solutions that lead to better, faster and more cost-effective ways of doing business. It has provided management training and networking to the industry’s leaders for almost 100 years. For more information, visit TAPPI’s website: http://www.tappi.org