Nanotube

Boron nitride nanotube (11)
Carbon nanotube (525)
Metallic nanotube (5)
Nanotube (302)
Nanotube transistor (7)
Semiconducting nanotubes (6)

Synopsis: Nanotechnology: Nanostructures: Nanotube:

#Nanotubes: Can we make speakers as thin as paper? It's time for one of those imagined futures

a thin, transparent film made from microscopic tubes called carbon nanotubes (CNTS), aligned parallel to the plane of the film.

gasgetting CNT films to emit sound is not the same as producing good-quality sound over the whole frequency range of human hearing,

So while the CNT speakers might have valuable applications such as sonar#they work perfectly well underwater#it isn't yet clear

One of the ways in which#to improve sound output is to surround the CNT film with a gas that has a lower heat capacity than air,

All things considered, Barnard and colleagues conclude that a high power CNT loudspeaker is feasible, but it won't be simple.

The CNT films will need probably to be enclosed and immersed in xenon, for example, which would pose serious challenges for making robust"wearable#speakers.

which is basically the same stuff as the walls of carbon nanotubes but flattened into sheets.

So one way or another, these forms of nanocarbon look destined to make our isles full of noises.

They can even lay down carbon nanotubes, tiny structures made of linked carbon atoms, and are working to align them to build futuristic circuits, according to Mccarroll.

but they say theye made a breakthrough that could take thermophotovoltaics far beyond where it gone before. mit thermophotovoltaics MIT nanophotonic solar thermophotovoltaic device, with an array of multialled carbon nanotubes as the absorber, a oneimensional silicon/silicon dioxide photonic crystal as the emitter

T) he team inserted a two-layer absorber-emitter device made of novel materials including carbon nanotubes and photonic crystals between the sunlight and the PV cell.

is an array of multiwalled carbon nanotubes, which very efficiently absorbs the light energy and turns it to heat.

so that when it is heated by the attached layer of nanotubes, it lows ith light whose peak intensity is mostly above the bandgap of the adjacent PV,

and nanotubes By injecting carbon nanotubes into the bloodstream, scientists can use near-infrared lasers to see blood flow in a living animal brain.

or NIR-IIA, involves injecting water-soluble carbon nanotubes into a live mouse bloodstream. The researchers then shine a near-infrared laser over the rodent skull.

The light causes the specially designed nanotubes to fluoresce at wavelengths of 1, 300-1, 400 nanometers;

The fluorescing nanotubes can then be detected to visualize the blood vesselsstructure. Amazingly, the technique allows scientists to view about three millimeters underneath the scalp

Second, injecting carbon nanotubes needs approval for clinical application; the scientists are currently investigating alternative fluorescent agents.

#Handheld terahertz cameras could replace MRI Rice university rightoriginal Studyposted by Mike Williams-Rice on June 11 2014scientists have used carbon nanotubes to create compact terahertz sensors that operate at room temperature.

The scientific community has long been interested in the terahertz properties of carbon nanotubes says Franãois LÃNARD a scientist at Sandia National Laboratories.

and his team have investigated terahertz phenomena in carbon nanotubes but those have focused mainly on the use of one or a bundle of nanotubes.

The problem LÃNARD says is that terahertz radiation typically requires an antenna to achieve coupling into a single nanotube due to the relatively large size of terahertz waves.

The researchers however found a way to create a small detector that is visible to the naked eye.

The thin carbon nanotube film developed by Rice chemist Robert Hauge and graduate student Xiaowei He does not require an antenna

Carbon nanotube thin films are extremely good absorbers of electromagnetic light he explains. In the terahertz range the film a mix of metallic

and semiconducting nanotubes soaks up all of the incoming terahertz radiation. rying to do that with a different kind of material would be nearly impossible

But that s what we ve achieved with the carbon nanotubes. The research was reported in the journal Nano Letters.

The chip, festooned with tiny carbon nanotubes (engineered segments of carbon that are efficient electrical conductors) and treated with a proprietary polymer

Star and his team have developed similar chip/nanotube sensors that can be affixed to a toothbrush to detect bad breath (the presence of hydrogen sulfide)

#New nanothreads are like diamond necklaces Scientists say super-thin iamond nanothreadsould be stronger and stiffer than the strongest nanotubes

The tricky bit according to Rice university chemist Angel Martã is keeping the densely packed nanotubes apart before they re drawn together into a fiber.

Left to their own devices carbon nanotubes form clumps that are perfectly wrong for turning into the kind of strong conductive fibers needed for projects ranging from nanoscale electronics to macro-scale power grids.

Earlier research at Rice by chemist and chemical engineer Matteo Pasquali a coauthor of the new paper used an acid dissolution process to keep the nanotubes separated until they could be spun into fibers.

and lead authors Chengmin Jiang a graduate student and Avishek Saha a Rice alumnus starts with negatively charging carbon nanotubes by infusing them with potassium a metal and turning them into a kind of salt known as a polyelectrolyte.

otherwise dampen the nanotubes ability to repel one another. Put enough nanotubes into such a solution and they re caught between the repellant forces

and an inability to move in a crowded environment Martã says. They re forced to align a defining property of liquid crystals

and tightly binds the nanotubes together says Martã an assistant professor of chemistry and bioengineering and of materials science and nanoengineering.

But to make macroscopic materials Martã s team needed to pack many more nanotubes into the solution than in previous experiments. s you start increasing the concentration the number of nanotubes in the liquid crystalline phase becomes more abundant than those in the isotropic (disordered) phase

The researchers discovered that 40 milligrams of nanotubes per milliliter gave them a thick gel after mixing at high speed

and filtering out whatever large clumps remained. t s like a centrifuge together with a rotary drummartã says of the mixing gear. t produces unconventional forces in the solution. eeding this dense nanotube gel through a narrow needle-like opening produced

and the team is investigating ways to improve their electrical properties through doping the nanotubes with iodide. he research is basically analogous to

but gave the process a spin with a different preparation so now we re the first to make neat fibers of pure carbon nanotube electrolytes.

because the setup is sealed. he nanotube electrolyte solution could be protected from oxygen and water which would have caused precipitation of the nanotubeshe says. t turns out that this is not a showstopper

because we want the nanotubes to precipitate and stick to each other as soon as they exit the sealed system through the needle.

and DNA the assembly of nanotechnological components or small organic polymers or the chemical alteration of carbon nanotubes. e need to continue to optimize the system

and nanotubes Stanford university rightoriginal Studyposted by Bjorn Carey-Stanford on August 7 2014by injecting carbon nanotubes into the bloodstream scientists can use near-infrared lasers to see blood flow in a living animal s brain.

or NIR-IIA involves injectingâ water-soluble carbon nanotubes into a live mouse s bloodstream. The researchers then shine a near-infrared laser over the rodent s skull.

The light causes the specially designed nanotubes to fluoresce at wavelengths of 1300-1400 nanometers;

The fluorescing nanotubes can then be detected to visualize the blood vessels structure. Amazingly the technique allows scientists to view about three millimeters underneath the scalp

Second injecting carbon nanotubes needs approval for clinical application; the scientists are currently investigating alternative fluorescent agents.

The Research center for Exotic Nanocarbons in Japan and the Center for Nanoscale Science at Penn State supported the research u

or PDMS, and carbon nanotubes. HOW IT WORKS When the terahertz light hits the transducer, the nanotubes absorb it,

turning it into heat. They pass that heat on to the PDMS. The heated PDMS expands,

and solar cells but Pint and Westover are confident that the rules that govern the load-bearing character of their design will carry over to other materials such as carbon nanotubes and lightweight porous metals like aluminum.

#DNA motor uses arms to walk across a nanotube Purdue University rightoriginal Studyposted by Emil Venere-Purdue on December 19 2013engineers made a motor out of DNA

and then used it to move nanoparticles of cadmium disulfide along the length of a nanotube.

As it moves along a carbon-nanotube track it continuously harvests energy from strands of RNA molecules vital to a variety of roles in living cells

and viruses. ur motors extract chemical energy from RNA molecules decorated on the nanotubes and use that energy to fuel autonomous walking along the carbon nanotube trackchoi says.

The core is made of an enzyme that cleaves off part of a strand of RNA. After cleavage the upper DNA arm moves forward binding with the next strand of RNA

The process repeats until reaching the end of the nanotube track. The researchers combined two fluorescent imaging systems to document the motor s movement one in the visible spectrum and the other in the near-infrared range.

and the nanotubes are fluorescent in the near-infrared. The motor took about 20 hours to reach the end of the nanotube which was several microns long

but the process might be sped up by changing temperature and ph a measure of acidity.

and medical devices to structural components for the automotive civil and aerospace industries. he cellulose nanocrystals represent a potential green alternative to carbon nanotubes for reinforcing materials such as polymers and concrete.

but graphene nanoribbons (GNRS) unzipped from multiwalled carbon nanotubes in a chemical process invented by the Tour group in 2009 do the job nicely he says.

Volman suggests the material would make a compelling competitor to recently touted nanotube-based aerogels for deicing airplanes in the winter. e have the technology;

#Tiny Lego blocks build two-faced nanotubes University of Warwick rightoriginal Studyposted by Anna Blackaby-Warwick on November 14 2013using a process similar to molecular Lego scientists

and can be controlled with a much higher level of accuracy than natural channel proteins. hrough a process of molecular engineeringâ##a bit like molecular Legoâ##we have assembled the nanotubes from two types of building blocksâ##cyclic peptides

and polymers. anus nanotubes are a versatile platform for the design of exciting materials which have a wide range of application from membranesâ##for instance for the purification of waterâ##to therapeutic uses including the development of new drug systems. ource:

Tour s breakthrough nzippingtechnique for turning multiwalled carbon nanotubes into GNRS first revealed in Nature in 2009 has been licensed for industrial production. hese are being produced in bulk

#Does this carbon nanotube computer spell the end for silicon? Stanford university rightoriginal Studyposted by Tom Abate-Stanford on September 27 2013engineers have built a basic computer using carbon nanotubes a success that points to a potentially faster more efficient alternative to silicon chips.

The achievement is reported in an article on the cover of the journal Nature. eople have been talking about a new era of carbon nanotube electronics moving beyond siliconsays Subhasish Mitra an electrical engineer

and computer scientist at Stanford university who co-led the work. ut there have been few demonstrations of complete digital systems using this exciting technology.

Here is the proof. xperts say the achievement will galvanize efforts to find successors to silicon chips which could soon encounter physical limits that might prevent them from delivering smaller faster cheaper electronic devices. arbon nanotubes CNTS have long been considered as a potential successor to the silicon transistorsays Professor

But until now it hasn t been clear that CNTS a semiconductor material could fulfill those expectations. here is no question that this will get the attention of researchers in the semiconductor community

Mihail Roco a senior advisor for nanotechnology at the National Science Foundation called the work n important scientific breakthrough. t was roughly 15 years ago that carbon nanotubes were fashioned first into transistors the on-off switches

But a bedeviling array of imperfections in these carbon nanotubes has frustrated long efforts to build complex circuits using CNTS.

team has made to this worldwide effort. irst they put in place a process for fabricating CNT-based circuitsde Micheli says. econd they built a simple

but effective circuit that shows that computation is doable using CNTS. s Mitra says: t s not just about the CNT COMPUTER.

It s about a change in directions that shows you can build something real using nanotechnologies that move beyond silicon

He called the Stanford work major benchmarkin moving CNTS toward practical use. CNTS are long chains of carbon atoms that are extremely efficient at conducting and controlling electricity.

They are so thinâ##thousands of CNTS could fit side by side in a human hairâ##that it takes very little energy to switch them off according to Wong a co-author of the paper. hink of it as stepping on a garden hosewong explains. he thinner the hose the easier it is to shut off the flow. n theory this combination

of efficient conductivity and low-power switching make carbon nanotubes excellent candidates to serve as electronic transistors. NTS could take us at least an order of magnitude in performance beyond where you can project silicon could take uswong said.

But inherent imperfections have stood in the way of putting this promising material to practical use.

First CNTS do not necessarily grow in neat parallel lines as chipmakers would like. Over time researchers have devised tricks to grow 99.5 percent of CNTS in straight lines.

But with billions of nanotubes on a chip even a tiny degree of misaligned tubes could cause errors

so that problem remained. A second type of imperfection has stymied also CNT technology. Depending on how the CNTS grow a fraction of these carbon nanotubes can end up behaving like metallic wires that always conduct electricity instead of acting like semiconductors that can be switched off.

Since mass production is the eventual goal researchers had to find ways to deal with misaligned

and/or metallic CNTS without having to hunt for them like needles in a haystack. e needed a way to design circuits without having to look for imperfections

or even know where they weremitra says. The Stanford paper describes a two-pronged approach that the authors call an mperfection-immune design. o eliminate the wire-like

or metallic nanotubes the Stanford team switched off all the good CNTS. Then they pumped the semiconductor circuit full of electricity.

All of that electricity concentrated in the metallic nanotubes which grew so hot that they burned up

This sophisticated technique eliminated the metallic CNTS in the circuit. Bypassing the misaligned nanotubes required even greater subtlety.

The Stanford researchers created a powerful algorithm that maps out a circuit layout that is guaranteed to work no matter

whether or where CNTS might be askew. his imperfections-immune design technique makes this discovery truly exemplarysays Sankar Basu a program director at the National Science Foundation.

Their CNT COMPUTER performed tasks such as counting and number sorting. It runs a basic operating system that allows it to swap between these processes.

In a demonstration of its potential the researchers also showed that the CNT COMPUTER could run MIPS a commercial instruction set developed in the early 1980s by then Stanford engineering professor and now university President John Hennessy.

Though it could take years to mature the Stanford approach points toward the possibility of industrial-scale production of carbon nanotube semiconductors according to Naresh Shanbhag a professor at the University of Illinois at Urbana-Champaign

and director of SONIC a consortium of next-generation chip design research. he Wong/Mitra paper demonstrates the promise of CNTS in designing complex computing systemsshanbhag says adding that this will motivate researchers elsewhere toward greater efforts in chip design

beyond silicon. hese are initial necessary steps in taking carbon nanotubes from the chemistry lab to a real environmentsays Supratik Guha director of physical sciences for IBM s Thomas J. Watson Research center

and a world leader in CNT research. The National Science Foundation SONIC the Stanford Graduate Fellowship and the Hertz Foundation Fellowship funded the work.

And because e-jet can naturally handle fluid inks it is suited exceptionally well for patterning solution suspensions of nanotubes nanocrystals nanowires

Rice university chemist James Tour and colleagues, who developed a method for unzipping nanotubes into graphene nanoribbons (GNRS),

since graphene (and its cousin material, carbon nanotubes) is the only material with the high strength-to-weight ratio required for this kind of hypothetical application.

each sensor utilizes an array of tens of thousands of carbon nanotubes, which have had copper atoms attached to them.

While electrons ordinarily flow freely through the nanotubes, any ethylene molecules present in the vicinity will bond with the copper atoms,

which absorb ethylene and concentrate it near the nanotubes. By measuring how much the electron flow has been slowed,

#Explosives and Pesticides Can Be detected by Using Bee venom Scientists from MIT have discovered that by coating carbon nanotubes in bee venom,

But the sensors aren just useful for explosives the researchers found that the coated nanotubes can also detect two pesticides that contain nitro-aromatic compounds.

##Researchers at#USC s Viterbi School of Engineeringhave created a#functioning synapse#using neurons made from carbon nanotubes.

Of course, duplicating synapse firings in nanotube circuits does not mean that scientists are ready to replace the human brain,

#Commercial nanotube transistors could be ready by 2020 Each chip on this wafer has 10,000 nanotube transistors on it.

A project at IBM is now aiming to have built transistors using carbon nanotubes ready to take over from silicon transistors soon after 2020.

who leads the company s nanotube project at the company s T. J. Watson research center in Yorktown Heights,

New york. Nanotubes are the only technology that looks capable of keeping the advance of computer power from slowing down,

In 1998, researchers at IBM made one of the first working carbon nanotube transistors. And now after more than a decade of research, IBM is the first major company to commit to getting the technology ready for commercialization.

Hannon led IBM s nanotube work before Haensch, who took over in 2011 after a career working on manufacturing conventional chips.

This is the point IBM hopes nanotubes can step in. The most recent report from the microchip industry group the ITRS says the so-called five-nanometernode is due in 2019.

000 nanotube transistors. Now it is working on a transistor design that could be built on the silicon wafers used in the industry today with minimal changes to existing design and manufacturing methods.

IBM s chosen design uses six nanotubes lined up in parallel to make a single transistor.

Each nanotube is 1. 4 nanometers wide about 30 nanometers long, and spaced roughly eight nanometers apart from its neighbors.

The IBM team has tested nanotube transistors with that design, but so far it hasn t found a way to position the nanotubes closely enough together,

because existing chip technology can t work at that scale. The favored solution is to chemically label the substrate

and nanotubes with compounds that would cause them to self-assemble into position. Those compounds could then be stripped away,

leaving the nanotubes arranged correctly and ready to have electrodes and other circuitry added to finish a chip.

Haensch s team buys nanotubes in bulk from industrial suppliers and filters out the tubes with the right properties for transistors using a modified version of a machine used to filter molecules such as proteins in the pharmaceutical industry.

It uses electric charge to separate semiconducting nanotubes useful for transistors from those that conduct electricity like metals

Last year researchers at Stanford created the first simple computer built using only nanotube transistors. But those components were bulky and slow compared to silicon transistors

says However, for now IBM s nanotube effort remains within its research labs, not its semiconductor business unit.

In particular, if the nanotube transistors are not ready soon after 2020 when the industry needs them,

If nanotubes don t make it, there s little else that shows much potential to take over from silicon transistors in that time frame.

and unlike carbon nanotubes, they don t behave similarly to silicon transistors, says Hannon. Subhasish Mitra, a professor who worked on the project.

We now know that you can build something useful with carbon nanotubes, he says. The question is,

Although IBM hasn worked t out how to make nanotube transistors small enough for mass production, Mirta says it has made concrete steps,

when they reinforced the polymer with carbon nanotubes, it became 50 percent stronger. IBM Research's James Hedrick, who co-authored the new paper,

Baughman has made artificial muscles out of carbon nanotube yarns before but those are much more expensive and complicated to make.

The new muscles contract to about 50 percent of their length compared with carbon nanotubes which contract to only about 10 percent their initial length he said.

Our electronic whiskers consist of high-aspect-ratio elastic fibers coated with conductive composite films of nanotubes and nanoparticles.

what the paper describes as highly tunable composite films of carbon nanotubes and silver nanoparticles that are patterned on high-aspect-ratio elastic fibers.

The nanotubes provide both flexibility allowing the whiskers to bend when they experience pressure and conductivity allowing them to transmit data on the environmental factors they experience.

A handful work at room temperature (by using carbon nanotubes to detect electrons for example2), but they cannot operate in water#a serious obstacle to using such devices in living organisms.

But in the new work they instead used carbon nanotubes atom-thick sheets of carbon rolled into cylinders grown on the slopes of the emitters like trees on a mountainside.

and height of the nanotubes the researchers were able to achieve a fluid flow that enabled an operating ion current at very near the theoretical limit.

To control the nanotubes growth the researchers first cover the emitter array with an ultrathin catalyst film

The nanotubes grow up under the catalyst particles which sit atop them until the catalyst degrades.

Using their nanotube forest they re able to get the devices to operate in pure ion mode

Grossman team tried attaching the molecules to carbon nanotubes (CNTS), but t incredibly hard to get these molecules packed onto a CNT in that kind of close packing,

Kucharski says. But then they found a big surprise: Even though the best they could achieve was a packing density less than half of

called azobenzene, protrude from the sides of the CNTS like the teeth of a comb.

they were interleaved with azobenzene molecules attached to adjacent CNTS. The net result: The molecules were actually much closer to each other than expected.

The interactions between azobenzene molecules on neighboring CNTS make the material work, Kucharski says. While previous modeling showed that the packing of azobenzenes on the same CNT would provide only a 30 percent increase in energy storage,

the experiments observed a 200 percent increase. New simulations confirmed that the effects of the packing between neighboring CNTS,

as opposed to on a single CNT, explain the significantly larger enhancements. This realization, Grossman says,

opens up a wide range of possible materials for optimizing heat storage. Instead of searching for specific photoswitching molecules

The adoption of carbon nanotubes to increase materialsenergy storage density is lever, says Yosuke Kanai, an assistant professor of chemistry at the University of North carolina who was involved not in this work.

In a new Nature Materials paper, the researchers report boosting plantsability to capture light energy by 30 percent by embedding carbon nanotubes in the chloroplast,

Using another type of carbon nanotube, they also modified plants to detect the gas nitric oxide. Together

the researchers also embedded semiconducting carbon nanotubes, coated in negatively charged DNA, into the chloroplasts. Plants typically make use of only about 10 percent of the sunlight available to them,

but carbon nanotubes could act as artificial antennae that allow chloroplasts to capture wavelengths of light not in their normal range, such as ultraviolet, green,

With carbon nanotubes appearing to act as a rosthetic photoabsorber photosynthetic activity measured by the rate of electron flow through the thylakoid membranes was 49 percent greater than that in isolated chloroplasts without embedded nanotubes.

When nanoceria and carbon nanotubes were delivered together, the chloroplasts remained active for a few extra hours. The researchers then turned to living plants

and used a technique called vascular infusion to deliver nanoparticles into Arabidopsis thaliana, a small flowering plant.

the nanotubes moved into the chloroplast and boosted photosynthetic electron flow by about 30 percent.

Lean green machines The researchers also showed that they could turn Arabidopsis thaliana plants into chemical sensors by delivering carbon nanotubes that detect the gas nitric oxide,

Strano lab has developed previously carbon nanotube sensors for many different chemicals, including hydrogen peroxide, the explosive TNT, and the nerve gas sarin.

When the target molecule binds to a polymer wrapped around the nanotube, it alters the tube fluorescence. e could someday use these carbon nanotubes to make sensors that detect in real time, at the single-particle level,

free radicals or signaling molecules that are at very low-concentration and difficult to detect, Giraldo says. his is a marvelous demonstration of how nanotechnology can be coupled with synthetic biology to modify

To create these ynthetic antibodies, the researchers used carbon nanotubes hollow, nanometer-thick cylinders made of carbon that naturally fluoresce

In the past, researchers have exploited this phenomenon to create sensors by coating the nanotubes with molecules, such as natural antibodies, that bind to a particular target.

the carbon nanotube fluorescence brightens or dims. The MIT team found that they could create novel sensors by coating the nanotubes with specifically designed amphiphilic polymers polymers that are drawn to both oil and water, like soap.

This approach offers a huge array of recognition sites specific to different targets, and could be used to create sensors to monitor diseases such as cancer, inflammation,

or diabetes in living systems. his new technique gives us an unprecedented ability to recognize any target molecule by screening nanotube-polymer complexes to create synthetic analogs to antibody function,

Moreover, this approach can provide a more durable alternative to coating sensors such as carbon nanotubes with actual antibodies,

Their approach takes advantage of a phenomenon that occurs when certain types of polymers bind to a carbon nanotube.

when the polymers are exposed to carbon nanotubes, the hydrophobic regions latch onto the tubes like anchors

These loops form a new layer surrounding the nanotube, known as a corona. The MIT researchers found that the loops within the corona are arranged very precisely along the tube,

and alter the carbon nanotube fluorescence. Molecular interactions What is unique about this approach, the researchers say,

and the polymer before it attaches to the nanotube. he idea is that a chemist could not look at the polymer

It has to adsorb onto the nanotube and then, by having certain sections of the polymer exposed,

The researchers used an automated, robot-assisted trial and error procedure to test about 30 polymer-coated nanotubes against three dozen possible targets, yielding three hits.

They are now working on a way to predict such polymer-nanotube interactions based on the structure of the corona layers,

using data generated from a new type of microscope that Landry built to image the interactions between the carbon nanotube coronas

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