#Lab unzips nanotubes into ribbons by shooting them at a target (Phys. org) Carbon nanotubes unzipped into graphene nanoribbons by a chemical process invented at Rice university are finding use in all kinds of projects
but Rice scientists have now found a chemical-free way to unzip them. The Rice lab of materials scientist Pulickel Ajayan discovered that nanotubes that hit a target end first turn into mostly ragged clumps of atoms.
But nanotubes that happen to broadside the target unzip into handy ribbons that can be used in composite materials for strength
and applications that take advantage of their desirable electrical properties. The Rice researchers led by graduate student Sehmus Ozden reported their finding in the American Chemical Society journal Nano Letters.
Until now we knew we could use mechanical forces to shorten and cut carbon nanotubes. This is the first time we have showed carbon nanotubes can be unzipped using mechanical forces.
The researchers fired pellets of randomly oriented multiwalled carbon nanotubes from a light gas gun built by the Rice lab of materials scientist Enrique Barrera with funding from NASA.
The pellets impacted an aluminum target in a vacuum chamber at about 15000 miles per hour. When they inspected the resulting carbon rubble they found nanotubes that smashed into the target end first
or at a sharp angle simply deformed into a crumpled nanotube. But tubes that hit lengthwise actually split into ribbons with ragged edges.
Hypervelocity impact tests are used mostly to simulate the impact of different projectiles on shields spacecraft
We were investigating possible applications for carbon nanotubes in space when we got this result. The effect was confirmed through molecular simulations.
Single-wall nanotubes do just the opposite; when the tube flattens the bottom wall hits the inside of the top wall
Ozden explained that the even distribution of stress along the belly-flopping nanotube which is many times longer than it is wide breaks carbon bonds in a line nearly simultaneously.
The researchers said 70 to 80 percent of the nanotubes in a pellet unzip to one degree or another.
Ozden said the process eliminates the need to clean chemical residues from nanoribbons produced through current techniques.
One-step chemical-free clean and high-quality graphene nanoribbons can be produced using our method. They're potential candidates for next-generation electronic materials he said.
Scientists shoot carbon nanotubes out of high-speed gun (w/video) More information: Unzipping Carbon nanotubes at High Impact.
Sehmus Ozden Pedro A s. Autreto Chandra Sekhar Tiwary Suman Khatiwada Leonardo Machado Douglas S. Galvao Robert Vajtai Enrique V. Barrera
#Diamond plates create nanostructures through pressure not chemistry You wouldn't think that mechanical forcehe simple kind used to eject unruly patrons from bars,
or emboss the raised numerals on credit cardsould process nanoparticles more subtly than the most advanced chemistry.
and original method uses simple pressure kind of high-tech embossingo produce finer and cleaner results in forming silver nanostructures than do chemical methods,
when applied to nanoparticle arrays, forms new nanostructures with tunable properties.""There is a great potential market for this technology,
The pressure, delivered by two diamond plates tightened by four screws to any controlled setting, shepherds silver nanospheres into any desired volume.
Propinquity creates conditions that produce nanorods, nanowires and nanosheets at chosen thicknesses and lengths rather than the one-size-fits-all output of a chemical process, with no environmentally harmful residues.
While experiments reported in the paper were performed with silverhe most desirable metal because it is the most conductive,
platinum and other metallic nanoparticles Clem said the researchers are now starting to work with semiconductors.
A coating of nanoparticles that can build into another structure has a certain functionality we don't have right now.
For example, under pressure, the dimensions of ordered three-dimensional nanoparticle arrays shrink. By fabricating a structure in
the nanoparticle array will remain at a constant state, able to transmit light and electricity with specific characteristics.
At even higher pressures, nanoparticles are forced to sinter, or bond, forming new classes of chemically
and mechanically stable nanostructures that no longer need restraining surfaces. These cannot be manufactured using current chemical methods.
composition and phase orientation of the initial nanoparticle arrays, a variety of nanostructures or nanocomposites and 3-D interconnected networks are achievable.
#Eco-friendly versatile nanocapsules developed The Institute for Basic Science (IBS) has announced that the Centre for Self-assembly
and Complexity have succeeded in developing a new technology that introduces metal nanoparticles on the surface of polymer nanocapsules made of cucurbit 6 uril.
The researchers have found that using polymer nanocapsules made of cucurbit 6 uril and metal salts can serve as a versatile platform where equal sized metal nanoparticles can be distributed evenly on the surface of the polymer nanocapsules.
Cucurbit 6 uril has properties which strongly and selectively recognize organic and inorganic chemical species. This makes it possible to use it as a protecting agent
which can stabilize metal nanoparticles by preventing them from clustering together. The metal nanoparticle-decorated polymer nanocapsules exhibit the following properties in water:
high stability for up to 6 months; high dispersibility; excellent catalytic activity; and reusability in carbon-carbon and carbon-nitrogen bond-forming reactions with 100%conversion efficiency.
Even though metal nanoparticles are used variously in industrial, pharmaceutical and agricultural (fertilizer) applications as a catalyst, toxic liquids such as toluene and hexane are used usually as solvents in the carbon-carbon
However, this new technology is able to replace those toxic liquids as it allows carbon-carbon and carbon-nitrogen bond-formation with the use of metal nanoparticles as a catalyst
and reusability in water, which other existing metal nanoparticles on solid supports have not been able to do,
"It is important as it presents new possible applications in green solvents or bioimaging and nanomedicine fields
#Scientists develop a'nanosubmarine'that delivers complementary molecules inside cells With the continuing need for very small devices in therapeutic applications there is a growing demand for the development of nanoparticles that can transport
Recently researchers created nanoparticles that under the right conditions self-assemble trapping complementary guest molecules within their structure.
Like tiny submarines these versatile nanocarriers can navigate in the watery environment surrounding cells and transport their guest molecules through the membrane of living cells to sequentially deliver their cargo.
Although the transport of molecules inside cells with nanoparticles has been achieved previously using various methods researchers have developed nanoparticles capable of delivering
For practical applications these nanocarriers are highly desirable explains Francisco Raymo professor of chemistry in the University of Miami College of Arts and Sciences and lead investigator of this project.
The new nanocarriers are15 nanometers in diameter. They are made supramolecular constructs up of building blocks called amphiphilic polymers.
These nanocarriers hold the guest molecules within the confines of their water-insoluble interior and use their water-soluble exterior to travel through an aqueous environment.
As a result these nanovehicles are ideal for transferring molecules that would otherwise be insoluble in water across a liquid environment.
if the nanoparticles can actually travel through the bloodstream. That would be the dream but we have no evidence that they can actually do so Raymo says.
The size of these nanoparticles their dynamic character and the fact that the reactions take place under normal biological conditions (at ambient temperature
and neutral environment) makes these nanoparticles an ideal vehicle for the controlled activation of therapeutics directly inside the cells Raymo says.
#Smart gating nanochannels for confined water developed Confined water exists widely and plays important roles in natural environments, particularly inside biological nanochannels.
Professor Lei Jiang and his group from State Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, set out to study this unified bionic frontier.
After several years of innovative research, they developed a series of biomimetic nanochannels, delivered a strategy for the design
and construction of smart nanochannels and applied the nanochannels in energy conversion systems. The author thought the inner surface property was the base for confined transportation.
entitled"Construction of biomimetic smart nanochannels for confined water",was published in National Science Review. Nature has inspired always greatly technology, engineering and significant inventions.
For example, the lotus can realize the self-cleaning effect using its micro/nanocomposite structure. The water striders can walk easily
and freely on the water surface via the special micro-and nanostructure on their legs.
Recently, Jiang's group focused on the confined water in one dimensional nanostructure materials. The study examined the confined water on the outer surfaces of one dimensional nano-structured materials including spider silk and cactus thorn,
They also studied confined water existing in nanochannel, which included the construction and application of bio-inspired nanochannels.
In this review Prof. Jiang expatiated the confined water that exists in one-dimensional micro/nano composite structures in detail, particularly inside biological nanochannels.
Using these nanochannels as inspiration, they provided a strategy for the design and construction of biomimetic smart nanochannels.
Importantly, they have applied the abiotic analogs to energy conversion systems. The confined water, that is water confined in micro-or mesopores,
not only plays an important role in maintaining the existence and development of living organisms, but also concerns the sustainable development of human society.
and cactus thorn showed the confined water collection on these one dimensional nanostructures was helpful in solving the shortage of freshwater resources.
biological ion channels played key roles for high efficient energy conversion in organisms due to its nanoscale effect and ion selectivity.
much effort has been directed toward building the functional unit with nanometer multistage, multiple scale, asymmetric structure, and so on,
#Bacterial nanometric amorphous Fe-based oxide as lithium-ion battery anode material Leptothrix ochracea is a species of iron-oxidizing bacteria that exists in natural hydrospheres where groundwater outwells worldwide.
and easily-handled electrode material since its basic texture is composed of nanometric particles. The charge-discharge properties of simple L-BIOX/Li-metal cells were examined at current rates of 33. 3ma/g (0. 05c)
Notably the presence of minor components of Si and P in the original L-BIOX nanometric particles resulted in specific and well-defined electrode architecture.
Research and applications of iron oxide nanoparticles More information: Bacterial Nanometric Amorphous Fe-Based Oxide: A Potential Lithium-Ion Battery Anode Material.
Hideki Hashimoto Genki Kobayashi Ryo Sakuma Tatsuo Fujii Naoaki Hayashi Tomoko Suzuki Ryoji Kanno Mikio Takano and Jun Takada.
#Nanoparticles could provide easier route for cell therapy UT Arlington physics researchers may have developed a way to use laser technology to deliver drug and gene therapy at the cellular level without damaging surrounding tissue.
the team paired crystalline magnetic carbon nanoparticles and continuous wave near-infrared laser beams for in
and Mohanty used a 50 to 100 milliwatt laser and the same carbon nanoparticle, which absorbs the beam,
continuous wave near-infrared laser and the nanoparticle to permeate the cell membrane without killing the cells.
whose lab created the study's crystalline magnetic carbon nanoparticle using an electric plasma discharge inside a toulene solution.
A significant advantage of the new method is that the near-infrared light absorption of the nanoparticle can be used to selectively amplify interaction of low power laser with targeted tissue
The magnetic properties of the nanoparticles also mean they can be localized with an external magnetic field;
"Carbon nanoparticles produced for the cancer study varied from five to 20 nanometers wide. A human hair is about 100,000 nanometers wide.
The magnetic carbon nanoparticles also are fluorescent. So, they can be used to enhance contrast of optical imaging of tumors along with that of MRI I
#Metal particles in solids aren't as fixed as they seem memristor study shows In work that unmasks some of the magic behind memristors and"resistive random access memory,
They observed the metal atoms becoming charged ions, clustering with up to thousands of others into metal nanoparticles,
#Scientists shoot carbon nanotubes out of high-speed gun (w/video)( Phys. org) What happens when you shoot multiwalled carbon nanotubes (MWCNTS) out of a gun onto an aluminum target at a velocity of more than 15000 mph?
Scientists finally have the answer. If a nanotube reaches the target at a 90â°angle (head-on) it will break
and deform quite drastically. However if it is parallel to the target upon impact the nanotube will unzip resulting in a 2d graphene nanoribbon.
This observation is unexpected since previous simulations have shown that nanotubes break into pieces when subjected to large mechanical forces.
Researchers Sehmus Ozden et al. at Rice university in Houston Texas US; the State university of Campinas in Campinas Brazil;
and the Indian Institute of Science in Bangalore India have published a paper on the results of their high-impact nanotube collision experiments in a recent issue of Nano Letters.
Because it was not possible to directly observe the impact due to the nanotubes'small size
and high speed the researchers analyzed the differences in the nanotubes using a transmission electron microscope before and after the impact to extract useful information about
Although each bundle of nanotubes (the pellet) was shot perpendicular to the target the individual randomly aligned nanotubes impacted the target at different angles.
At a 90â°impact angle the nanotubes deformed along the radial direction essentially being smashed like the front of a car in a head-on collision.
At a 45â°impact angle the nanotubes became partly deformed and partly unzipped. At a 0â°angle the nanotubes were unzipped completely
when shot at the aluminum target. The researchers explain that the unzipping occurs on the scale of femtoseconds.
In that short time many atoms along the side of the nanotube become stressed due to the impact resulting in the breaking of the carbon bonds in a straight line along the side of the nanotube.
Many of these atoms ended up being ejected from the nanotube rather than having their bonds neatly broken as in the 0â°impact angle scenario.
Unzipping carbon nanotubes to create 2d graphene nanoribbons is very useful in nanoscience but until now it has typically been achieved with chemical contaminants that leave back contaminants.
By demonstrating for the first time that nanotubes can be unzipped quickly through mechanical means the new study offers a clean-cut a clean chemical-free way to produce high-quality graphene nanoribbons.
As the researchers explained graphene nanoribbons have certain advantages over both nanotubes and graphene that make them attractive for applications.
Graphene nanoribbons are good candidates for active materials in electronics being the channel of field-effect transistors coauthor Dr. Robert Vajtai at Rice university told Phys. org.
They are superior to carbon nanotubes as their bandgap is more predictable. Also they are superior to graphene itself as graphene has no bandgap
but making a nanometer scale narrow stripe of it opens the bandgap because of quantum confinement so it is a semiconductor.
Explore further: Hybrid nanotube-graphene material promises to simplify manufacturing More information: Sehmus Ozden et al. Unzipping Carbon nanotubes at High Impact.
Nano Letters. DOI: 10.1021/nl501753 0
#Super-stretchable yarn is made of graphene A simple, scalable method of making strong, stretchable graphene oxide fibers that are scrolled easily into yarns
and have strengths approaching that of Kevlar is possible, according to Penn State and Shinshu University, Japan, researchers."
"We found this graphene oxide fiber was very strong, much better than other carbon fibers,"said Mauricio Terrones, professor of physics, chemistry and materials science and engineering, Penn State."
"We believe that pockets of air inside the fiber keep it from being brittle.""This method opens up multiple possibilities for useful products, according to Terrones and colleagues.
For instance, removing oxygen from the graphene oxide fiber results in a fiber with high electrical conductivity. Adding silver nanorods to the graphene film would increase the conductivity to the same as copper,
which could make it a much lighter weight replacement for copper transmission lines. The researchers believe that the material lends itself to many kinds of highly sensitive sensors.
The researchers made a thin film of graphene oxide by chemically exfoliating graphite into graphene flakes,
which were mixed then with water and concentrated by centrifugation into a thick slurry. The slurry was then spread by bar coatingomething like a squeegeecross a large plate.
When the slurry dries it becomes a large-area transparent film that can be lifted carefully off without tearing.
The design is based on the use of microlattices with nanoscale features, combining great stiffness and strength with ultralow density,
#New approach may be key to quantum dot solar cells with real gains in efficiency (Phys. org) Los alamos researchers have demonstrated an almost fourfold boost of the carrier multiplication yield with nanoengineered quantum dots.
Quantum dots are novel nanostructures that can become the basis of the next generation of solar cells capable of squeezing additional electricity out of the extra energy of blue and ultraviolet photons.
but is enhanced appreciably in ultrasmall semiconductor particles also called quantum dots as was demonstrated first by LANL researchers in 2004 (Schaller & Klimov Phys.
In conventional quantum dots however carrier multiplication is not efficient enough to boost the power output of practical devices.
A new study conducted within the Center for Advanced Solar Photophysics demonstrates that appropriately engineered core/shell nanostructures made of lead selenide
and cadmium selenide (Pbse and Cdse) can increase the carrier multiplication yield fourfold over simple Pbse quantum dots.
To realize the effect of slowed carrier cooling LANL researchers have fabricated Pbse quantum dots with an especially thick Cdse shell.
Qianglu Lin a CASP student working on the synthesis of these materials said A striking feature of the thick-shell Pbse/Cdse quantum dots is fairly bright visible emission from the shell observed simultaneously with the infrared emission from the core.
While the present CASP work is based on Pbse/Cdse quantum dots the concept of carrier-multiplication engineering through control of intraband cooling is general
and should be realizable with other combinations of materials and/or nanostructure geometries. Jeff Pietryga lead CASP chemist says Further enhancement in carrier multiplication should be possible by combining this new approach with other demonstrated means for increasing multicarrier yields such as by using shape-control
(as in nanorods) and/or materials in which cooling is already naturally slower like Pbte.
Applied together these strategies might provide a practical route to nanostructures exhibiting carrier multiplication performance approaching the limits imposed by energy conservation n
researchers from the USC Viterbi School of engineering describe how they have overcome a major issue in carbon nanotube technology by developing a flexible,
energy-efficient hybrid circuit combining carbon nanotube thin film transistors with other thin film transistors. This hybrid could take the place of silicon as the traditional transistor material used in electronic chips,
since carbon nanotubes are more transparent, flexible, and can be processed at a lower cost. Electrical engineering professor Dr. Chongwu Zhou and USC Viterbi graduate students Haitian Chen
and Jialu Zhang developed this energy-efficient circuit by integrating carbon nanotube (CNT) thin film transistors (TFT) with thin film transistors comprised of indium, gallium and zinc oxide (IGZO)."
"Before then, we were working hard to try to turn carbon nanotubes into n-type transistors and then one day,
Instead of working so hard to force nanotubes to do something that they are not good for,
"Carbon nanotubes are so small that they can only be viewed through a scanning electron microscope. This hybridization of carbon nanotube thin films and IGZO thin films was achieved by combining their types, p-type and n-type, respectively,
to create circuits that can operate complimentarily, reducing power loss and increasing efficiency. The inclusion of IGZO thin film transistors was necessary to provide power efficiency to increase battery life.
If only carbon nanotubes had been used, then the circuits would not be power-efficient. By combining the two materials,
Zhou likened the coupling of carbon nanotube TFTS and IGZO TFTS to the Chinese philosophy of yin and yang."
With this development, Zhou and his team have circumvented the difficulty of creating n-type carbon nanotube TFTS
and p-type IGZO TFTS by creating a hybrid integration of p-type carbon nanotube TFTS and n-type IGZO TFTS and demonstrating a large-scale integration of circuits.
Up to this point, all carbon nanotube-based transistors had a maximum number of 200 transistors.""We believe this is a technological breakthrough,
"The next step for Zhou and his team will be to build more complicated circuits using a CNT
"Zhou and Chen believe that carbon nanotube technology, including this new CNT-IGZO hybrid, will be commercialized in the next 5-10 years."
"I believe that this is just the beginning of creating hybrid integrated solutions, "said Zhou.""We will see a lot of interesting work coming up. g
#Sixteen nanometres in 3d Tomography enables the interior of a vast range of objects to be depicted in 3d from cellular structures to technical appliances.
Until now, the relevant details on a scale of a few nanometres were only visible with methods that required very thin samples.
With the aid of a special prototype setup at the PSI's Swiss Light source (SLS) the researchers have achieved now a 3d resolution of sixteen nanometres on a nanoporous glass test sample
It is specialized for studies where researchers are interested in details that are a few nanometres in size, such as the fine structures of cell components or modern catalysts and batteries.
For thick samples, hard X-ray tomography was limited to a resolution of around 150 nanometres. For many years, X-ray tomography has been conducted at various synchrotron light sources, such as The swiss Light source at the PSI.
During the measurement, they were able to achieve a spatial resolution of sixteen nanometres and achieve a world record."
So we had to know the position of the sample to within a few nanometres throughout the entire measurement,
#DNA-linked nanoparticles form switchable'thin films'on a liquid surface Scientists seeking ways to engineer the assembly of tiny particles measuring just billionths of a meter have achieved a new firsthe formation of a single
layer of nanoparticles on a liquid surface where the properties of the layer can be switched easily.
In addition, because the scientists used tiny synthetic strands of DNA to hold the nanoparticles together
the study also offers insight into the mechanism of interactions of nanoparticles and DNA molecules near a lipid membrane.
This understanding could inform the emerging use of nanoparticles as vehicles for delivering genes across cellular membranes."
"Our work reveals how DNA-coated nanoparticles interact and reorganize at a lipid interface, and how that process affects the properties of a"thin film"made of DNA-linked nanoparticles,
"said physicist Oleg Gang who led the study at the Center for Functional Nanomaterials (CFN) at the U s. Department of energy's Brookhaven National Laboratory.
The results will be published in the June 11, 2014 print edition of the Journal of the American Chemical Society.
the synthetic DNA strands used as"glue"to bind nanoparticles in this study have a natural tendency to pair up
Scientists at Brookhaven have made great use of the specificity of this attractive force to get nanoparticles coated with single synthetic DNA strands to pair up
"Many of the applications we envision for nanoparticles, such as optical coatings and photovoltaic and magnetic storage devices, require planar geometry,
Other groups of scientists have assembled such planes of nanoparticles, essentially floating them on a liquid surface,
"Using DNA linker molecules gives us a way to control the interactions between the nanoparticles."
a lipid, has a strong positive charge it attracts the negatively charged DNA strands that coat the nanoparticles.
That electrostatic attraction and the repulsion between the negatively charged DNA molecules surrounding adjacent nanoparticles overpower the attractive force between COMPLEMENTARY DNA bases.
and link the nanoparticles together more closely, first forming string-like arrays, and with more salt, a more solid yet elastic mesh-like layer."
when the particle sizes and the DNA chain sizes are comparablen the order of 20-50 nanometers,
As part of the study, the scientists examined the different configurations of the nanoparticles on top of the liquid layer using x-ray scattering at Brookhaven's National Synchrotron Light source (NSLS.
or nanoscale objects through liquid interfaces. For example, said Gang, when particles are linked but move freely at the interface,
Because of the nanoscale size-regime, we might envision using such membranes for filtering proteins or other nanoparticles,
Understanding how synthetic DNA-coated nanoparticles interact with a lipid surface may also offer insight into how such particles coated with actual genes might interact with cell membraneshich are composed largely of lipidsnd with one another in a lipid environment."
"Other groups have considered using DNA-coated nanoparticles to detect genes within cells, or even for delivering genes to cells for gene therapy
I believe this approach has significant value as a platform for more detailed investigations of realistic systems important for these new biomedical applications of DNA NANOPARTICLE pairings,
#Charging portable electronics in 10 minutes Researchers at the University of California Riverside Bourns College of Engineering have developed a three-dimensional silicon-decorated cone-shaped carbon nanotube cluster architecture for lithium ion battery anodes that could enable charging of portable
In a paper Silicon Decorated Cone Shaped Carbon nanotube Clusters for Lithium ion battery Anode recently published in the journal Small UC Riverside researchers developed a novel structure of three-dimensional silicon decorated cone-shaped
carbon nanotube clusters architecture via chemical vapor deposition and inductively coupled plasma treatment. Lithium ion batteries based on this novel architecture demonstrate a high reversible capacity and excellent cycling stability.
One the seamless connection between graphene covered copper foil and carbon nanotubes enhances the active material-current collector contact integrity
#Technology using microwave heating may impact electronics manufacture Engineers at Oregon State university have shown successfully that a continuous flow reactor can produce high-quality nanoparticles by using microwave-assisted heating essentially the same forces
are essentially a"proof of concept"that a new type of nanoparticle production system should actually work at a commercial level."
"Nanoparticles are extraordinarily small particles at the forefront of advances in many biomedical, optical and electronic fields,
researchers worked with lead selenide nanoparticles, which are particularly good for the taggant technologies. Other materials can be synthesized using this reactor for different applications,
Shoei Electronic Materials, one of the collaborators, is pursuing"quantum dot"systems based on this approach, and recently opened new manufacturing facilities in Eugene, Ore.,
to use this synthetic approach for quantum dot enabled televisions, smartphones and other devices d
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