ONE Box Girl Scout Cookies = $15 Billion (Converting Carbon Sources to Graphene)


mix-id328072.jpgRice University lab shows troop how any carbon source can become valuable graphene.
Scientists can make graphene out of just about anything with carbon — even Girl Scout cookies.

Graduate students in the Rice University lab of chemist James Tour proved it when they invited a troop of Houston Girl Scouts to their lab to show them how it’s done.

 

*** WOW! Team GNT KNEW we should have bought more Girl Scout Cookies in this year’s annual ‘cookie drive’!  – Cheers!

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With carbon nanotubes, a path to flexible, low-cost sensors


Nano Particles for Steel 324x182(Nanowerk News) Researchers at the Technische  Universitaet Muenchen (TUM) are showing the way toward low-cost,  industrial-scale manufacturing of a new family of electronic devices. A leading  example is a gas sensor that could be integrated into food packaging to gauge  freshness, or into compact wireless air-quality monitors. New types of solar  cells and flexible transistors are also in the works, as well as pressure and  temperature sensors that could be built into electronic skin for robotic or  bionic applications. All can be made with carbon nanotubes, sprayed like ink  onto flexible plastic sheets or other substrates.
Carbon nanotube-based gas sensors created at TUM offer a unique  combination of characteristics that can’t be matched by any of the alternative  technologies. They rapidly detect and continuously respond to extremely small  changes in the concentrations of gases including ammonia, carbon dioxide, and  nitrogen oxide. They operate at room temperature and consume very little power.  Furthermore, as the TUM researchers report in their latest papers, such devices  can be fabricated on flexible backing materials through large-area, low-cost  processes.
Flexible carbon nanotube Gas Sensors
Flexible, high-performance gas sensors (left) were made by spraying  a solution of carbon nanotubes (right) onto a plastic backing.
Thus it becomes realistic to envision plastic food wrap that  incorporates flexible, disposable gas sensors, providing a more meaningful  indicator of food freshness than the sell-by date. Measuring carbon dioxide, for  example, can help predict the shelf life of meat. “Smart packaging” – assuming  consumers find it acceptable and the devices’ non-toxic nature can be  demonstrated – could enhance food safety and might also vastly reduce the amount  of food that is wasted. Used in a different setting, the same sort of gas sensor  could make it less expensive and more practical to monitor indoor air quality in  real time.
Not so easy – but “really simple”
Postdoctoral researcher Alaa Abdellah and colleagues at the TUM  Institute for Nanoelectronics have demonstrated that high-performance gas  sensors can be, in effect, sprayed onto flexible plastic substrates. With that,  they may have opened the way to commercial viability for carbon nanotube-based  sensors and their applications. “This really is simple, once you know how to do  it,” says Prof. Paolo Lugli, director of the institute.
The most basic building block for this technology is a single  cylindrical molecule, a rolled-up sheet of carbon atoms that are linked in a  honeycomb pattern. This so-called carbon nanotube could be likened to an  unimaginably long garden hose: a hollow tube just a nanometer or so in diameter  but perhaps millions of times as long as it is wide. Individual carbon nanotubes  exhibit amazing and useful properties, but in this case the researchers are more  interested in what can be done with them en masse.
Laid down in thin films, randomly oriented carbon nanotubes form  conductive networks that can serve as electrodes; patterned and layered films  can function as sensors or transistors. “In fact,” Prof. Lugli explains, “the  electrical resistivity of such films can be modulated by either an applied  voltage (to provide a transistor action) or by the adsorption of gas molecules,  which in turn is a signature of the gas concentration for sensor applications.”
And as a basis for gas sensors in particular, carbon nanotubes  combine advantages (and avoid shortcomings) of more established materials, such  as polymer-based organic electronics and solid-state metal-oxide semiconductors.  What has been lacking until now is a reliable, reproducible, low-cost  fabrication method.
Spray deposition, supplemented if necessary by transfer  printing, meets that need. An aqueous solution of carbon nanotubes looks like a  bottle of black ink and can be handled in similar ways. Thus devices can be  sprayed – from a computer-controlled robotic nozzle – onto virtually any kind of  substrate, including large-area sheets of flexible plastic. There is no need for  expensive clean-room facilities.
“To us it was important to develop an easily scalable technology  platform for manufacturing large-area printed and flexible electronics based on  organic semiconductors and nanomaterials,” Dr. Abdellah says. “To that end,  spray deposition forms the core of our processing technology.”
Remaining technical challenges arise largely from  application-specific requirements, such as the need for gas sensors to be  selective as well as sensitive.
Publications
Fabrication of carbon nanotube thin films on  flexible substrates by spray deposition and transfer printing. Ahmed  Abdelhalim, Alaa Abdellah, Giuseppe Scarpa, Paolo Lugli. Carbon, Vol.  61, September 2013, 72-79.
Flexible carbon nanotube-based gas sensors  fabricated by large-scale spray deposition. Alaa Abdellah, Zubair Ahmad,  Philipp Köhler, Florin Loghin, Alexander Weise, Giuseppe Scarpa, Paolo Lugli.  IEEE Sensors Journal, Vol. 13 Issue 10, October 2013, 4014-4021.
Scalable spray deposition process for high  performance carbon nanotube gas sensors. Alaa Abdellah, Ahmed Abdelhalim,  Markus Horn, Giuseppe Scarpa, and Paolo Lugli. IEEE Transactions on  Nanotechnology 12, 174-181, 2013.
Source: Technische Universität München 

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New Form of Carbon Stronger Than Graphene and Diamond


Carbon NanotubeChemists have calculated that chains of double or triple-bonded carbon atoms, known as carbyne, should be stronger and stiffer than any known material. 

 

The sixth element, carbon, has given us an amazing abundance of extraordinary materials. Once there was simply carbon, graphite and diamond. But in recent years chemists have added buckyballs, nanotubes and any number of exotic shapes created out of graphene, the molecular equivalent of chickenwire.

So it’s hard to believe that carbon has any more surprises up its sleeve. And yet today, Mingjie Liu and pals at Rice University in Houston calculate the properties of another form of carbon that is stronger, stiffer and more exotic than anything chemists have seen before.

The new material is called carbyne. It is a chain of carbon atoms that are linked either by alternate triple and single bonds or by consecutive double bonds.

Carbyne is something of a mystery. Astronomers believe they have detected its signature in interstellar space but chemists have been bickering for decades over whether they had ever created this stuff on Earth. A couple of years ago, however, they synthesised carbyne chains up to 44 atoms long in solution.

The thinking until now has been that carbyne must be extremely unstable. In fact some chemists have calculates that two strands of carbyne coming into contact would react explosively.

Nevertheless, nanotechnologists have been fascinated with potential of this material because it ought to be both strong and stiff and therefore useful. But exactly how strong and how stiff, no one has been quite sure.

This is where Liu and co step in. These guys have calculated from first principles the bulk properties of carbyne and the results make for interesting reading.  

For a start, they say that carbyne is about twice as stiff as the stiffest known materials today. Carbon nanotubes and grapheme, for example, have a stiffness of 4.5 x 10^8 N.m/kg but carbyne tops them with a stiffness of around 10^9 N.m/kg.

Just as impressive is the new material’s strength. Liu and co calculate that it takes around 10 nanoNewtons to break a single strand of carbyne. “This force translates into a specific strength of 6.0–7.5×10^7 N∙m/kg, again significantly outperforming every known material including graphene (4.7–5.5×10^7 N∙m/ kg), carbon nanotubes (4.3–5.0×10^7 N∙m/ kg), and diamond (2.5–6.5×10”7 N∙m/kg4),” they say.

Carbyne has other interesting properties too. Its flexibility is somewhere between that of a typical polymer and double-stranded DNA. And when twisted, it can either rotate freely or become torsionally stiff depending on the chemical group attached to its end.

Perhaps most interesting is the Rice team’s calculation of carbyne’s stability.  They agree that two chains in contact can react but there is an activation barrier that prevents this happening readily. “This barrier suggests the viability of carbyne in condensed phase at room temperature on the order of days,” they conclude.

All this should whet the appetite of nanotechnologists hoping to design ever more exotic nanomachines, such as nanoelectronic and spintronic devices.  Given the advances being made in manufacturing this stuff, we may not have long to wait before somebody begins exploiting the extraordinary mechanical properties of carbyne chains for real.

Ref: arxiv.org/abs/1308.2258 : Carbyne From First Principles: Chain Of C Atoms, A Nanorod Or A Nanorope?

Linde Electronics’ Carbon Nanotube Inks to Drive Innovation in Next-generation Electronic Devices


QDOTS imagesCAKXSY1K 8(Nanowerk News) Linde Electronics, the global  electronics business of The Linde Group, launched a revolutionary new carbon  nanotube ink to drive innovation in the development of next generation displays,  sensors and other electronic devices. Linde’s carbon nanotube inks can be used  to manufacture completely new technologies, such as a smartphone with a screen  that rolls up like a window shade and a see-through GPS device embedded in the  windshield of a car.                      

Carbon nanotubes are an allotrope of carbon like graphite and  diamond, and they have unique physical and electronic properties. These include  a higher thermal conductivity than diamond; greater mechanical strength than  steel (orders of magnitude by weight); and a larger electrical conductivity than  copper. It is due to these properties that carbon nanotubes will enable  electronic device manufacturers develop more innovative electronic devices.                      

To help device manufacturers and the research and development  community to explore the full potential of carbon nanotube based technologies,  Linde is making its nanotube inks available to developers. These nanotube inks  contain individual carbon nanotubes and are produced without damaging or  shortening the nanotubes and therefore preserve the unique nanotube properties. 

This landmark development drastically improves the performance of transparent  conductive thin films made from the inks and opens the door for the development  of nanotube applications in not only consumer electronics, but also the  healthcare sector and sensor manufacturing.                      

“While we’ve seen a lot of excitement around nanotubes in the  past ten years, we’ve not yet seen a commercially viable nanotube solution in  the market because of challenges in the processing of this great material,” said  Dr Sian Fogden, Market and Technology Development Manager for Linde Electronics’  nanomaterials unit. “Our nanotube technology and our unique nanotube inks  overcome these challenges, paving the way for completely new types of  high-functionality electronic devices.”                      

Linde, which develops and supplies specialist materials and  gases for the world’s leading electronic manufacturers, is in the final  development stages with its single wall carbon nanotube technology. Alongside  the launch of the nanotube ink into the development community, the company will  also provide its nanotube ink at large scale directly to electronic device  manufacturers.                      

About The Linde Group                     

The Linde Group is a world-leading gases and engineering company  with around 62,000 employees in more than 100 countries worldwide. In the 2012  financial year, Linde generated revenue of EUR 15.280 bn. The strategy of the  Group is geared towards long-term profitable growth and focuses on the expansion  of its international business with forward-looking products and services. Linde  acts responsibly towards its shareholders, business partners, employees, society  and the environment — in every one of its business areas, regions and locations  across the globe. The company is committed to technologies and products that  unite the goals of customer value and sustainable development.

For more  information, see The Linde Group online at http://www.linde.com

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