#Creating nanostructures using simple stamps Nanostructures of virtually any possible shape can now be made using a combination of techniques developed by the MESA+Institute for Nanotechnology of the University of Twente.
#Researcher develops optically traceable smart 2-D nanosheet that responds to ph Nanoparticles have the potential to revolutionize the medical industry
the nanosheet. Specifically he designed a strong stable and optically traceable smart 2-D material that responds to ph or the acidity or basicity of its surrounding environment.
Nanosheets are unusual amongst nanotechnology because they do not exactly conform to nanoscale. The sheets that Kim produced are just a few nanometers thick thin enough to earn the nano prefix.
much larger than typical nanostructures.##Nanosheets'structure gives them the ability to change shape from a flat surface to a scroll.
Unfortunately most nanosheets roll and unroll spontaneously. If researchers can design a nanosheet to change form in response to a stimulus they can use it for a number of new applications.
Kim tried adding different polymers to his nanosheets to make them responsive. For this experiment he incorporated a relatively simple polymer that responds to ph. He found that the resulting nanosheet would always curl in basic high ph conditions
and always flatten in acidic low ph conditions. Kim also made his nanosheets responsive to near-infrared light a wavelength of light that is harmless to humans.
Depending on the shape of the nanosheet the near-infrared radiation bounces back with a different wavelength.
In this way Kim can noninvasively track the nanosheets even though he can't see them. Using these optical properties to characterize the nanosheets Kim determined that he could approximate ph. Kim envisions biomedical engineers wrapping drugs inside of scrolled nanosheets
so that when the sheet unrolls it releases the medicine. PH responsive nanosheets for example could prove useful for targeting different parts of the human digestive tract
which changes ph between the acidic stomach and basic intestines. Yet this is only the beginning;
creating a responsive nanosheet is just a matter of adding the right polymer. A nanosheet is like pizza dough Kim said.
Whatever you like to put on it#one topping two toppings anything#you can. A nanosheet with a heat-sensitive polymer could burn surrounding tumors to destroy them functioning as a kind of super-specific chemotherapy.
It's easy to get the nanosheets to the cancer cells explains Kim. Targeting specific tissues is simply a matter of adding the appropriate biomarker
so that the body sends the nanosheet where it belongs. The advantage of the rolling means that this nanosheet can entrap many markers
or drugs securely inside the body said Kim. By encapsulating a dangerous substance such as a cancer-treating drug into a nanosheet doctors can attack very specific parts of the body.
This would decrease the amount of the drug necessary and minimize side effects. There are tons of smart polymers
and metals Kim said explaining the many properties he hopes to incorporate into nanotechnology. This new structure is composite
which means it allows us to mix all different kinds of components. Now Kim just needs to build the right nanosheet for each purpose.
Explore further: Like cling wrap new biomaterial can coat tricky burn wounds and block out infection More information:
Smart Composite Nanosheets with Adaptive Optical Properties Jeong-Hwan Kim Murtaza Bohra Vidyadhar Singh Cathal Cassidy and Mukhles Sowwan Applied materials & Interfaces2014.
American Chemical Society DOI: 10.1021/am504170
#New nanomaterial introduced into electrical machines Lappeenranta University of Technology in Finland has constructed the world's first prototype electrical motor using carbon nanotube yarn in the motor windings.
The new technology may significantly enhance the performance. Engineers of LUT have constructed the world's first electrical motor applying a textile material;
carbon nanotube yarn. The presently most electrically conductive carbon nanotube yarn replaces usual copper wires in the windings.
The motor prototype is built by the LUT Electrical engineering group as a start towards lightweight efficient electric drives.
The test motor output power is 40 W it rotates at 15000 rpm and has almost a 70%efficiency.
In the near future carbon nanotube fibers have potential to significantly enhance the performance and energy efficiency of electrical machines.
The best carbon nanotubes (CNTS) have demonstrated conductivities far beyond those of the best metals. Thus future windings made of CNTS may have a double conductivity compared with the present-day copper windings.
In order to make CNTS easy to manipulate they are spun to form multifiber yarn. If we keep the electrical machine design parameters unchanged and only replace copper with future carbon nanotube wires it is possible to reduce the Joule losses in the windings to half of the present-day machine losses.
Carbon nanotube wires are significantly lighter than copper and also environmentally friendlier. Therefore replacing copper with nanotube wires should significantly reduce the CO2 EMISSIONS related to the manufacturing
and operating of electrical machines. Furthermore the machine dimensions and masses could be reduced. The motors could also be operated in significantly higher temperatures than the present ones says Professor Juha Pyrh nen who has led the design of the prototype at LUT.
No definite upper limit for the conductivity Traditionally the windings in electrical machines are made of copper which has the second best conductivity of metals at room temperature.
Despite the high conductivity of copper a large proportion of the electrical machine losses occur in the copper windings.
The carbon nanotube yarn does not have a definite upper limit for conductivity (e g. values of 100 MS/m have already been measured.
The prototype motor uses carbon nanotube yarns spun and converted into an isolated tape by a Japanese-Dutch company Teijin Aramid
We expect that in the future the conductivity of carbon nanotube yarns could be even three times the practical conductivity of copper in electrical machines.
Carbon nanotube fibers outperform coppe e
#New absorber will lead to better biosensors Biological sensors or biosensors are like technological canaries in the coalmine.
Aydin and his team have created a new nanostructure that absorbs a very narrow spectrum of light#having a bandwidth of just 12 nanometers.
By using nanofabrication techniques in the lab Aydin's team found that removing the insulating layer#leaving only metallic nanostructures#caused the structure to absorb a much narrower band of light.
#Nanoparticles accumulate quickly in wetland sediment (Phys. org) A Duke university team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting an action they say could indirectly damage the aquatic food chain.
But the researchers warn that based on their previous research the tendency for the nanotubes to accumulate in sediment could indirectly damage the aquatic food chain in the long term
Carbon nanotubes are rapidly becoming more common because of their usefulness in nanoelectric devices composite materials and biomedicine.
Ferguson and his colleagues dosed the mesocosms with single-walled carbon nanotubes and measured their concentrations in the water soil and living organisms during the course of a year.
and the animals that eat them Previous research has shown that carbon nanotubes take a long time to degrade through natural processes
whether or not these pollutants can be stripped away from the carbon nanotubes by these animals'digestive systems after being ingested continued Ferguson.
Biodistribution of carbon nanotubes in the body More information: Fate of single walled carbon nanotubes in wetland ecosystems. Schierz A. Espinasse B. Wiesner M. R. Bisesi J. H. Sabo-Attwood T. Ferguson P. L. Environmental science:
Nano Sept. 2014. DOI: 10.1039/c4en00063 3
#All directions are created not equal for nanoscale heat sources Thermal considerations are rapidly becoming one of the most serious design constraints in microelectronics, especially on submicron scale lengths.
Briseno with colleagues and graduate students at UMASS Amherst and others at Stanford university and Dresden University of Technology Germany report in the current issue of Nano Letters that by using single-crystalline organic nanopillars
or nanograss they found a way to get around dead ends or discontinuous pathways that pose a serious drawback when using blended systems known as bulk heterojunction donor-acceptor or positive-negative (p-n) junctions for harvesting energy in organic solar cells.
We report here that we have developed at last the ideal architecture composed of organic single-crystal vertical nanopillars.
Nanopillars are engineered nanoscale surfaces with billions of organic posts that resemble blades of grass and like grass blades they are particularly effective at converting light to energy.
In this case the anisotropy is along the nanopillar perpendicular to the substrate. Briseno says The biggest challenge in producing this architecture was finding the appropriate substrate that would enable the molecules to stack vertically.
Vertical nanopillars are ideal geometries for getting around these challenges Briseno says because charge separation/collection is most efficient perpendicular to the plastic device.
In this case our nanopillars highly resemble nanograss. Our systems share similar attributes of grass such as high density array system vertical orientations
We envision that our nanopillar solar cells will appeal to low-end energy applications such as gadgets toys sensors and short lifetime disposable devices s
#Nanotube cathode beats large pricey laser Scientists are a step closer to building an intense electron beam source without a laser.
Using the High-Brightness Electron Source Lab at DOE's Fermi National Accelerator Laboratory a team led by scientist Luigi Faillace of Radiabeam Technologies is testing a carbon nanotube cathode about the size of a nickel
Tests with the nanotube cathode have produced beam currents a thousand to a million times greater than the one generated with a large pricey laser system.
While carbon nanotube cathodes have been studied extensively in academia Fermilab is the first facility to test the technology within a full-scale setting.
The exceptional strength of carbon nanotubes prevents the cathode from being destroyed. Traditionally accelerator scientists use lasers to strike cathodes
The tested nanotube cathode requires no laser: it only needs the electric field already generated by an accelerator to siphon the electrons off a process dubbed field emission n
and carbon nanotubes is one of the most promising novel technology for producing inexpensive printed solar cells.
Physicists at Umeå University have discovered that one can reduce the number of carbon nanotubes in the device by more than 100 times
Carbon nanotubes are more and more attractive for use in solar cells as a replacement for silicon. They can be mixed in a semiconducting polymer
and the nanotubes have outstanding electrical conductivity, and they can effectively separate and transport electrical charges generated from solar energy.
if carbon nanotubes are connected to each other in a controlled manner to form complex nanosized networks, one can achieve significantly higher charge transport
Previous studies have reported that there is a percolation threshold for the amount of carbon nanotubes necessary to transport efficiently electric charges in a device.
and charge transport at very low nanotube loadings, thereby strongly reducing materials costs o
#Scientists improve microscopic batteries with homebuilt imaging analysis (Phys. org) In a rare case of having their cake
Miniature all-solid-state heterostructure nanowire Li-ion batteries as a tool for engineering and structural diagnostics of nanoscale electrochemical processes.
The researchers have built a novel nanostructure that offers a new platform for the development of highly stable and reliable nanoscale memory devices.
#New research points to graphene as a flexible low-cost touchscreen solution New research published today in the journal Advanced Functional Materials suggests that graphene-treated nanowires could soon replace current touchscreen technology
Researchers from the University of Surrey and AMBER the materials science centre based at Trinity college Dublin have demonstrated now how graphene-treated nanowires can be used to produce flexible touchscreens at a fraction of the current cost.
Using a simple scalable and inexpensive method the researchers produced hybrid electrodes the building blocks of touchscreen technology from silver nanowires and graphene.
Lead author Dr Izabela Jurewicz from the University of Surrey commented Our work has cut the amount of expensive nanowires required to build such touchscreens by more than fifty times as well as simplifying the production process.
Conductive nanofiber networks for flexible unbreakable and transparent electrode e
#Harnessing an unusual'valley'quantum property of electrons Yoshihiro Iwasa and colleagues from the RIKEN Center for Emergent Matter Science the University of Tokyo and Hiroshima University have discovered that ultrathin films of a semiconducting material have properties that form the basis for a new kind of low-power electronics termed'valleytronics'.
In the form of nanowires and nanoparticles it has particular potential for use in the manufacture of solar cells
It had already been demonstrated on nanowires made from one crystalline form of gallium arsenide the cubic so-called zincblende structure that the band gap widens under pressure.
The present research focused instead on nanowires of a less-common crystalline form the hexagonal so-called wurtzite structure.
They discovered the band gap that the electrons need to leap across to also widened although not as much as in the case of the zincblende crystal nanowires.
Significantly they discovered that around 207000 times normal atmospheric pressure (21 gigapascals) the wurtzite gallium arsenide nanowires underwent a structural change that induced a new phase the so-called orthorhombic one
or even a single nanowire and realize much more complex and useful electronic functions through interactions across the phases Goncharov said.
#Controlling photoluminescence with silicon nanophotonics for better devices Silicon nanowires have a great deal of potential in future high-performance electronic sensing and energy devices.
Red photoluminescence has been reported in silicon nanowires but for many applications this hampers device performance. As Tsuyoshi Okuno from the University of Electro-Communications and his colleagues point out in a recent report
Okuno and his colleagues fabricated silicon nanowire arrays by metal-assisted chemical etching an approach that is simple and cost-effective.
and etched nanowires using aqueous H2o2. Although the researchers did not have precise control over the nanowire morphology they did observe that higher concentrations of H2o2 led to thicker nanowires.
Photoluminescence studies did not reveal a link between photoluminescence and nanowire diameter or length alone but low aspect ratio nanowires exhibited red photoluminescence.
Further observations of the morphology identified silicon nanocrystals at the nanowire ends which was corroborated by Raman studies of single nanowires.
These nanocrystals disappear on annealing as does the red photoluminescence. The researchers attribute the red photoluminescence to defect states between nanocrystals and surrounding oxide and excitonic transitions.
As the researchers conclude in their report These results of Si nanowire arrays are believed to be useful for future optoelectronic and photovoltaic applications.
Oda K. Nanai Y. Sato T. Kimura S. & Okuno T. Correlation between photoluminescence and structure in silicon nanowires fabricated by metal-assisted etching.
or'top-down'methods widely used for the fabrication of nanostructures. Notably electrons in quantum dot structures are confined inside nanometer sized three dimension boxes.
#Fabrication route improves the properties of aluminum-based nanocomposites One challenge in producing strong elastic
and hard-wearing nanocomposites is obtaining an even distribution of the nanoparticles in the metal matrix.
Their technique is a viable new method for manufacturing nanocomposites and has exciting potential for the car space and defense industries.
The team used scanning electron microscopy to check two key properties that influence the strength of nanocomposites.
We plan to continue this research to further improve the mechanical and thermal properties as well as the wear resistance of the nanocomposites says Guo.
#Researchers uncover properties in nanocomposite oxide ceramics for reactor fuel Nanocomposite oxide ceramics have potential uses as ferroelectrics fast ion conductors
In a nanocomposite the size of each of these grains is on the order of nanometers roughly 1000 times smaller than the width of a human hair.
and radiation damage resistance of oxide nanocomposites by controlling the termination chemistry at the interface.
We believe that this discovery that the interface structure is sensitive to the chemistry of the interface will open the door for new research directions in oxide nanocomposites said Blas Uberuaga lead researcher on the effort.
Gan microstructures and nanostructures are garnering attention within the research community as light-emitting devices because of their variable-color light emission
#Nanotubes help healing hearts keep the beat (Phys. org) Carbon nanotubes serve as bridges that allow electrical signals to pass unhindered through new pediatric heart-defect patches invented at Rice university and Texas Children's Hospital.
and chemical engineer and chemist Matteo Pasquali created the patches infused with conductive single-walled carbon nanotubes.
The nanotubes overcome a limitation of current patches in which pore walls hinder the transfer of electrical signals between cardiomyocytes the heart muscle's beating cells
Nanotubes can fix that and Jacot who has a joint appointment at Rice and Texas Children's took advantage of the surrounding collaborative research environment.
We thought nanotubes could be integrated easily. Nanotubes enhance the electrical coupling between cells that invade the patch helping them keep up with the heart's steady beat.
When cells first populate a patch their connections are compared immature with native tissue Jacot said.
but the nanotubes forge a path around the obstacles. Jacot said the relatively low concentration of nanotubes 67 parts per million in the patches that tested best is key.
Earlier attempts to use nanotubes in heart patches employed much higher quantities and different methods of dispersing them.
Jacot's lab found a component they were already using in their patches#chitosan#keeps the nanotubes spread out.
Chitosan is amphiphilic meaning it has hydrophobic and hydrophilic portions so it can associate with nanotubes (which are hydrophobic)
and keep them from clumping. That's what allows us to use much lower concentrations than others have tried.
Because the toxicity of carbon nanotubes in biological applications remains an open question Pasquali said the fewer one uses the better.
and get to it with the fewest nanotubes possible he said. We can do this if we control dispersion well and use high-quality nanotubes.
The patches start as a liquid. When nanotubes are added the mixture is shaken through sonication to disperse the tubes
which would otherwise clump due to Van der waals attraction. Clumping may have been an issue for experiments that used higher nanotube concentrations Pasquali said.
The material is spun in a centrifuge to eliminate stray clumps and formed into thin fingernail-sized discs with a biodegradable polycaprolactone backbone that allows the patch to be sutured into place.
As a side benefit nanotubes also make the patches stronger and lower their tendency to swell
This is a good example of how it's much better for an application person like Dr. Jacot to work with experts who know how to handle nanotubes rather than trying to go solo as many do said he.
Biocompatible Carbon nanotube#Chitosan Cardiac Scaffold Matching the Electrical conductivity of the Heart. Seokwon Pok Flavia Vitale Shannon L. Eichmann Omar M. Benavides Matteo Pasquali and Jeffrey G Jacot ACS Nano Just Accepted Manuscript DOI:
and gold nanowires approx. 12 nanometres in diameter and 42 nanometres in length. The gold wire is therefore only about one ten-thousandth the thickness of a hair.
The microsphere and nanowire amplify the interaction between light and molecules. With the help of a prism, the researchers shine laser light into the microsphere.
Vollmer and his colleagues therefore fix a nanowire to the surface of the glass bead.
to the nanowire mounted on the microsphere. When a matching, i e. COMPLEMENTARY DNA fragment binds to the"bait"on the nanowire
the wavelength of the light shifts and is amplified by the microsphere and nanowire. This shift can be measured.
Different strand sections can be distinguished by their binding behaviour However, the physicists used a shorter DNA fragment than is usual in similar procedures.
#Nanoribbon film keeps glass ice-free: Team refines deicing film that allows radio frequencies to pass Rice university scientists who created a deicing film for radar domes have refined now the technology to work as a transparent coating for glass.
The material is made of graphene nanoribbons atom-thick strips of carbon created by splitting nanotubes a process also invented by the Tour lab
Last year the Rice group created films of overlapping nanoribbons and polyurethane paint to melt ice on sensitive military radar domes
In the previous process the nanoribbons were mixed with polyurethane but testing showed the graphene nanoribbons themselves formed an active network when applied directly to a surface.
He said nanoribbon films also open a path toward embedding electronic circuits in glass that are both optically and RF transparent a
#Aligned carbon nanotube/graphene sandwiches By in situ nitrogen doping and structural hybridization of carbon nanotubes (CNTS) and graphene via a two-step chemical vapor deposition (CVD) scientists have fabricated nitrogen-doped aligned carbon nanotube/graphene (N-ACNT/G) sandwiches
with three-dimensional (3d) electron transfer pathways interconnected ion diffusion channels and enhanced interfacial affinity and activity.
CNTS and graphene the most highlighted sp2-bonded carbon nanomaterials over the past decades have attracted enormous attention in the area of energy storage heterogeneous catalysis healthcare environmental protection as well as nanocomposites
However the heteroatom-containing nanocarbon tends to aggregate due to strong Van der waals interactions and large surface area explosion thereby constantly limiting the demonstration of their intrinsic physical properties and performances in as-fabricated materials and practical devices.
The combination of CNTS and graphene into 3d hybrid composites can usually mitigate the self-aggregation
and restacking of nanocarbon materials and also amplify physical properties at macroscale. Up to now several strategies have been explored to fabricate such CNTS/graphene hybrids including post-organization methods
and in situ growth while integration of high-quality CNTS and graphene without barrier layers is still difficult.
A team from Tsinghua University (China) led by Prof. Qiang Zhang and Fei Wei have fabricated now successfully sandwich-like N-ACNT/G hybrids via a two-step catalytic growth on bifunctional natural materials.
Aligned CNTS were intercalated firstly into the interlayer spaces of the layered catalyst embedded with metal nanoparticles (NPS) through a low-temperature (L-T) CVD
and graphene was deposited sequentially onto the surface of lamellar flakes at the bottom of aligned CNTS through a high-temperature (H-T) CVD.
After catalyst removal alternative aligned CNTS and graphene were connected vertically to each other in long-range periodicity thereby forming a sandwich-like structure.
The key issue for the fabrication of the novel N-ACNT/G architecture is that the high-quality aligned CNTS
Org''Thereby the seamless connection of high-quality aligned CNTS and graphene provided 3d electron transfer pathways and interconnected ion diffusion channels.
which was about 65%higher than that of sole aligned CNTS. Even at a high current density of 5. 0 C a reversible capacity of ca. 770 mah g-1 can be achieved.
Zhang elaborated The seamless junction of CVD-grown aligned CNTS and graphene provides rapid electron transfer and mechanical robustness.
It is expected highly that the N-ACNT/G sandwiches hold various potential applications in the area of nanocomposite energy storage environmental protection electronic device as well as healthcare because of their robust hierarchical structure 3d electron transfer
and fabrication strategy is generally applicable we foresee a new branch of material chemistry evolving in the area of advanced hierarchical nanostructures through the 3d topological nanosystems and interfacial modification.
Rational hybridization of N-doped graphene/carbon nanotubes for oxygen reduction and oxygen evolution reaction More information:
Tang C Zhang Q Zhao MQ Huang JQ Cheng XB Tian GL Peng HJ Wei F. Nitrogen-Doped Aligned Carbon nanotube
and then use those nanostructures like LEGO to construct larger materials, you can obtain nearly any set of properties you want.
what they call three-dimensional nanolattices that are formed by a repeating nanoscale pattern. After the patterning step,
and undoped graphene pieces they were able to form heterojunctions in the nanoribbons thereby fulfilling a basic requirement for electronic current to flow in only one direction
In a paper first published online on Sept. 9 in the journal Nature Chemistry, Mallouk and colleagues at Penn State and the Research center for Exotic Nanocarbons at Shinshu University, Japan, describe a method called intercalation,
either by patterning graphene to make nanoribbons or by introducing defects in the graphene layerr using bilayer graphene stacked in a certain pattern that allows band gap opening upon application of a vertical electric fieldor better control and detection of current.
While one-dimensional materials such as carbon nanotubes and nanowires also allow excellent electrostatics and at the same time possess band gap they are not suitable for low-cost mass production due to their process complexities she said.
At present the scientific community worldwide is actively seeking practical applications of 2d semiconductor materials such as Mos2 nanosheets.
and Swiss Federal Institute of technology in Zurich describe a basic model circuit consisting of a silver nanowire and a single-layer flake of molybendum disulfide (Mos2).
K. Goodfellow R. Beams C. Chakraborty L. Novotny A n. Vamivakas Integrated nanophotonics based on nanowire plasmons and atomically-thin material Optica Vol. 1 Issue
Along with colleagues at the University of Manchester researchers captured the world's first real-time images and simultaneous chemical analysis of nanostructures while underwater or in solution.
This lets scientists watch as nanostructures grow and change with time during chemical reactions. The team is now working with the manufacturer Protochips Inc. to make this capability available to the scientific community.
The study Real-time imaging and local elemental analysis of nanostructures in liquids was published in the journal Chemical Communications with researchers from the University of Manchester and BP.
Real-time imaging and local elemental analysis of nanostructures in liquids. Edward A. Lewis et al. Chem.
#Conductive nanofiber networks for flexible unbreakable and transparent electrodes Transparent conductors are required as electrodes in optoelectronic devices, such as touch panel screens, liquid crystal displays, and solar cells.
Tokyo Institute of technology researchers report the first development of a facile method for the fabrication of flexible and unbreakable transparent electrodes using nanofibers.
Two-dimensional aluminum (Al) nanofiber networks offering transparent conductors were fabricated by simple wet chemical etching of Al metalized polymer films using an electrospun polystyrene nanofiber mask template.
The resulting Al nanowire networksith a width of 500 nm and an area fraction of 22.0%xhibited 80%optical transmittance and sheet resistance of 45 O sq-1
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