Category Archives: Nano-Tech
Particle Trap Paves Way for Personalized Medicine
Scientists were able to trap a single particle between four microelectrodes, paving the way for a faster and cheaper way to sequence DNA. (Credit: Weihua Guan and Mark Reed/Yale University)
Sequencing DNA base pairs — the individual molecules that make up DNA — is key for medical researchers working toward personalized medicine. Being able to isolate, study and sequence these DNA molecules would allow scientists to tailor diagnostic testing, therapies and treatments based on each patient’s individual genetic makeup.
But being able to isolate individual molecules like DNA base pairs, which are just two nanometers across — or about 1/50,000th the diameter of a human hair — is incredibly expensive and difficult to control. In addition, devising a way to trap DNA molecules in their natural aqueous environment further complicates things. Scientists have spent the past decade struggling to isolate and trap individual DNA molecules in an aqueous solution by trying to thread it through a tiny hole the size of DNA, called a “nanopore,” which is exceedingly difficult to make and control.
Now a team led by Yale University researchers has proven that isolating individual charged particles, like DNA molecules, is indeed possible using a method called “Paul trapping,” which uses oscillating electric fields to confine the particles to a space only nanometers in size. (The technique is named for Wolfgang Paul, who won the Nobel Prize for the discovery.) Until now, scientists have only been able to use Paul traps for particles in a vacuum, but the Yale team was able to confine a charged test particle — in this case, a polystyrene bead — to an accuracy of just 10 nanometers in aqueous solutions between quadruple microelectrodes that supplied the electric field.
Their device can be contained on a single chip and is simple and inexpensive to manufacture. “The idea would be that doctors could take a tiny drop of blood from patients and be able to run diagnostic tests on it right there in their office, instead of sending it away to a lab where testing can take days and is expensive,” said Weihua Guan, a Yale engineering graduate student who led the project.
Story Continues -> Particle Trap Paves Way for Personalized Medicine
Novel Artificial Material Could Facilitate Wireless Power
Unique artificial materials should theoretically make it possible to improve the power transfer to small devices, such as laptops or cell phones, or ultimately to larger ones, such as cars or elevators, without wires, researchers say. (Credit: © Borodaev / Fotolia)
Electrical engineers at Duke University have determined that unique artificial materials should theoretically make it possible to improve the power transfer to small devices, such as laptops or cell phones, or ultimately to larger ones, such as cars or elevators, without wires.
This advance is made possible by the recent ability to fabricate exotic composite materials known as metamaterials, which are not so much a single substance, but an entire human-made structure that can be engineered to exhibit properties not readily found in nature. In fact, the metamaterial used in earlier Duke studies, and which would likely be used in future wireless power transmission systems, resembles a miniature set of tan Venetian blinds.
Theoretically, this metamaterial can improve the efficiency of “recharging” devices without wires. As power passes from the transmitting device to the receiving device, most if not all of it scatters and dissipates unless the two devices are extremely close together. However, the metamaterial postulated by the Duke researchers, which would be situated between the energy source and the “recipient” device, greatly refocuses the energy transmitted and permits the energy to traverse the open space between with minimal loss of power.
“We currently have the ability to transmit small amounts of power over short distances, such as in radio frequency identification (RFID) devices,” said Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke’s Pratt School of Engineering. “However, larger amounts of energy, such as that seen in lasers or microwaves, would burn up anything in its path.
“Based on our calculations, it should be possible to use these novel metamaterials to increase the amount of power transmitted without the negative effects,” Urzhumov said.
Story Continues – Novel Artificial Material Could Facilitate Wireless Power
Invisibility Cloak: Scientists Achieve Optical Invisibility in Visible Light Range of Spectrum
Electron micrograph of an invisibility cloak structure. The polymer-air metamaterial (“logs”) is colored blue, the gold-coated areas are colored yellow. (Credit: CFN)
“Seeing something invisible with your own eyes is an exciting experience,” say Joachim Fischer and Tolga Ergin. For about one year, both physicists and members of the team of Professor Martin Wegener at KIT’s Center for Functional Nanostructures (CFN) have worked on refining the structure of the Karlsruhe invisibility cloak to such an extent that it is also effective in the visible spectral range.
In invisibility cloaks, light waves are guided by the material such that they leave the invisibility cloak again as if they had never been in contact with the object to be disguised. Consequently, the object is invisible to the observer. The exotic optical properties of the camouflaging material are calculated using complex mathematical tools.
These properties result from a special structuring of the material. It has to be smaller than the wavelength of the light that is to be deflected. For example, the relatively large radio or radar waves require a material “that can be produced using nail scissors,” says Wegener. At wavelengths visible to the human eye, materials have to be structured in the nanometer range.
The minute invisibility cloak produced by Fischer and Ergin is smaller than the diameter of a human hair. It makes the curvature of a metal mirror appear flat, as a result of which an object hidden underneath becomes invisible. The metamaterial placed on top of this curvature looks like a stack of wood, but consists of plastic and air. These “logs” have precisely defined thicknesses in the range of 100 nm. Light waves that are normally deflected by the curvature are influenced and guided by these logs such that the reflected light corresponds to that of a flat mirror.
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Karlsruhe Institute of Technology.
Journal Reference:
- J. Fischer, T. Ergin, M. Wegener. Three-dimensional polarization-independent visible-frequency carpet invisibility cloak. Optics Letters, 2011; (in press)
Story Continues -> Invisibility Cloak: Scientists Achieve Optical Invisibility in Visible Light Range of Spectrum
New Nanolens Breaks Resolution Record
A new kind of lens reaches an unprecedentedly sharp focus by giving up on being perfect. The lens is the first ever to help take visual light images of structures smaller than 100 nanometers (four one-millionths of inch), which could make it useful for nanotechnology and probing the insides of cells.
Ordinary lenses, like those used in magnifying glasses, have curved surfaces that bend light to a single point. A small object sitting at that point appears larger and sharply focused, helping myopic readers discern fine print and old-school detectives search for fingerprints. But conventional lenses need to be almost perfect to work. Scratches and roughness destroy the clear image.
“Every deviation from the perfect surface results in a deteriorated focus,” said Elbert van Putten, a graduate student at the University of Twente in the Netherlands. “And in practice you’ll always see surface defects.”
The smallest object on which physicists have managed to focus a single conventional lens is 200 nanometers across, just larger than the smallest known bacteria (although more complicated microscopy systems have reached down to 50 nanometers). But a lot of structures that physicists and chemists are interested in, like subcellular structures, nanoelectric circuits and photonic structures, are less than half that size.
Story Continues -> New NanoLens
Turning Waste Heat Into Power
A “forest” of molecules holds the promise of turning waste heat into electricity. UA physicists discovered that because of quantum effects, electron waves traveling along the backbone of each molecule interfere with each other, leading to the buildup of a voltage between the hot and cold electrodes (the golden structures on the bottom and top). (Credit: Justin Bergfield, University of Arizona)
What do a car engine, a power plant, a factory and a solar panel have in common? They all generate heat — a lot of which is wasted.
University of Arizona physicists have discovered a new way of harvesting waste heat and turning it into electrical power.
Using a theoretical model of a so-called molecular thermoelectric device, the technology holds great promise for making cars, power plants, factories and solar panels more efficient, to name a few possible applications. In addition, more efficient thermoelectric materials would make ozone-depleting chlorofluorocarbons, or CFCs, obsolete.
The research group led by Charles Stafford, associate professor of physics, published its findings in the September issue of the scientific journal, ACS Nano.
“Thermoelectricity makes it possible to cleanly convert heat directly into electrical energy in a device with no moving parts,” said lead author Justin Bergfield, a doctoral candidate in the UA College of Optical Sciences.
“Our colleagues in the field tell us they are pretty confident that the devices we have designed on the computer can be built with the characteristics that we see in our simulations.”
“We anticipate the thermoelectric voltage using our design to be about 100 times larger than what others have achieved in the lab,” Stafford added.
Catching the energy lost through waste heat has been on the wish list of engineers for a long time but, so far, a concept for replacing existing devices that is both more efficient and economically competitive has been lacking.
Article Continues -> http://www.sciencedaily.com/releases/2010/09/100930154610.htm
Nanoparticles: Peering Into the Never-Before-Seen
Making adjustments to the dynamic transmission electron microscope. From left: Curtis Brown, Thomas LaGrange and Judy Kim. (Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory)
Scientists can now peer into the inner workings of catalyst nanoparticles 3,000 times smaller than a human hair within nanoseconds.
The findings point the way toward future work that could greatly improve catalyst efficiency in a variety of processes that are crucial to the world’s energy security, such as petroleum catalysis and catalyst-based nanomaterial growth for next-generation rechargeable batteries. The work was performed in a collaborative effort by Lawrence Livermore National Laboratory and the University of California at Davis.
Using a new imaging technique on Lawrence Livermore’s Dynamic Transmission Electron Microscope (DTEM), researchers have achieved unprecedented spatial and temporal resolution in single-shot images of nanoparticulate catalysts.
The DTEM uses a laser-driven photocathode to produce short pulses of electrons capable of recording electron micrographs with 15-nanosecond (one billionth of a second) exposure time. The recent addition of an annular dark field (ADF) aperture to the instrument has greatly improved its ability to time-resolve images of nanoparticles as small as 30 nanometers in diameter.
“Nanoparticles in this size range are of crucial importance to a wide variety of catalytic process of keen interest to energy and nanotechnology researchers,” said UC Davis’ Dan Masiel, formerly of LLNL and lead author of a paper appearing in the journal, ChemPhysChem. “Time-resolved imaging of such materials will allow for unprecedented insight into the dynamics of their behavior.”
Previously, particles smaller than 50 nanometers could not be resolved in the 15-nanosecond exposure because of the limited signal and low contrast without ADF aperature. But by using DTEM’s ADF, almost every 50-nanometer particle and many 30-nanometer ones became clearly visible because of the fast time resolution and high contrast.
“The stark difference between these two images clearly demonstrates the efficacy of annual dark field imaging when imaging samples with feature sizes near the resolution limit of DTEM,” Masiel said.
The new technique makes it easier to discern significant features when compared to bright field pulsed imaging. It allows for vastly improved contrast for smaller particles, widening the range of catalyst systems that can be studied using DTEM.
DTEM can record images with six orders of magnitude higher temporal resolution than conventional TEM and can provide important insights into processes such as phase transformations, chemical reactions and nanowire and nanotube growth.
Co-authors include LLNL’s Bryan Reed, Thomas LaGrange, Geoffrey Campbell, Ting Guo and Nigel Browning. The work was funded by the Department of Energy’s Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.
The article appears in the May 27 online edition of ChemPhys Chem.
Story Source:
The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by DOE/Lawrence Livermore National Laboratory.
Journal Reference:
- Daniel J. Masiel, Bryan W. Reed, Thomas B. LaGrange, Geoffrey H. Campbell, Ting Guo, Nigel D. Browning. Time-Resolved Annular Dark Field Imaging of Catalyst Nanoparticles. ChemPhysChem, 2010; DOI: 10.1002/cphc.201000274
http://www.sciencedaily.com/releases/2010/06/100616151635.htm
Self-Powered Flexible Electronics
On a bender: This machine is testing the electrical properties of a graphene sheet. Korean researchers have incorporated these stretchy electrodes with thin-film nano-generators to make an energy-harvesting screen. Credit: Advanced Materials
Touch-responsive nano-generator films could power touch screens.
Touch-screen computing is all the rage, appearing in countless smart phones, laptops, and tablet computers.
Now researchers at Samsung and Sungkyunkwan University in Korea have come up with a way to capture power when a touch screen flexes under a user’s touch. The researchers have integrated flexible, transparent electrodes with an energy-scavenging material to make a film that could provide supplementary power for portable electronics. The film can be printed over large areas using roll-to-roll processes, but are at least five years from the market.
The screens take advantage of the piezoelectric effect–the tendency of some materials to generate an electrical potential when they’re mechanically stressed. Materials scientists are developing devices that use nanoscale piezoelectronics to scavenge mechanical energy, such as the vibrations caused by footsteps. But the field is young, and some major challenges remain. The power output of a single piezoelectric nanowire is quite small (around a picowatt), so harvesting significant power requires integrating many wires into a large array; materials scientists are still experimenting with how to engineer these screens to make larger devices.
Samsung’s experimental device sandwiches piezoelectric nanorods between highly conductive graphene electrodes on top of flexible plastic sheets. The group’s aim is to replace the rigid and power-consuming electrodes and sensors used on the front of today’s touch-screen displays with a flexible touch-sensor system that powers itself. Ultimately, this setup might generate enough power to help run the display and other parts of the device functions. Rolling up such a screen, for instance, could help recharge its batteries.
“The flexibility and rollability of the nano-generators gives us unique application areas such as wireless power sources for future foldable, stretchable, and wearable electronics systems,” says Sang-Woo Kim, professor of materials science and engineering at Sungkyunkwan University. Kim led the research with Jae-Young Choi, a researcher at Samsung Advanced Institute of Technology.
The same group previously put nano-generators on indium tin oxide electrodes. This transparent, conductive material is used to make the electrodes on today’s displays, but it is inflexible.
To make the new nano-generators, the researchers start by growing graphene–a single-atom-thick carbon material that’s highly conductive, transparent, and stretchy–on top of a silicon substrate, using chemical vapor deposition. Next, through an etching process developed by the group last year, the graphene is released from the silicon; and the graphene is removed by rolling a sheet of plastic over the surface. The graphene-plastic substrate is then submerged in a chemical bath containing a zinc reactant and heated, causing a dense lawn of zinc-oxide nanorods to grow on its surface. Finally, the device is topped off with another sheet of graphene on plastic.
In a paper published this month in the journal Advanced Materials, the Samsung researchers describe several small prototype devices made this way. Pressing the screen induces a local change in electrical potential across the nanowires that can be used to sense the location of, for example, a finger, as in a conventional touch screen. The material can generate about 20 nanowatts per square centimeter. Kim says the group has subsequently made more powerful devices about 200 centimeters squared. These produce about a microwatt per square centimeter. Kim says this is enough for a self-powered touch sensor and “indicates we can realize self-powered flexible portable devices without any help of additional power sources such as batteries in the near future.”
“It’s pretty impressive to integrate all these things in a foldable, macroscale device,” says Michael McAlpine, professor of mechanical engineering at Princeton University. He notes that the potential of zinc oxide nanowires as a piezoelectric sensing material and nanoscale power source was previously demonstrated by Georgia Tech materials scientist Zhong Lin Wang. But integrating these materials over a large area with a flexible, transparent electrode opens up new applications, says McAlpine.
The methods used to make the nano-generators are compatible with large-scale manufacturing, according to Kim. His group is working to boost the power output of the films–the main obstacle is the quality of the electrodes. One possible solution is to improve the connection between the nanowires and the electrodes by eliminating flaws in the structure of the graphene. The Korean group is also experimenting with adding small amounts of impurities to the material, a process called doping, to improve its conductivity.
Nanotube Fibers
Chemical engineer Matteo Pasquali, who spins carbon nanotubes into fibers in his lab at Rice University in Houston. Credit: Tommy Lavergne
How to make strong, conductive fibers hundreds of meters long.
In a Rice University lab, a black fiber the diameter of a human hair spools into a beaker of ether. Made up of pure nanotubes, the strand is the culmination of nearly a decade of experimentation. Chemical engineer Matteo Pasquali and his colleagues have spun nanotubes into fibers several hundred meters long, proving that commercially useful manufacturing techniques can be developed to produce macroscale materials from these cylindrical molecules of pure carbon.
Making carbon nanotubes into fibers was a particular dream of the late Rice professor Richard Smalley, who shared the 1996 Nobel Prize in chemistry for his discovery of the spherical carbon molecules called buckyballs. Individual nanotubes have remarkable properties: they’re lightweight, they’re strong, and they can be electrically conductive. But assembling them into large structures with these properties has been difficult.
In 2001, Smalley began trying to use liquid processing to spin carbon nanotubes into fibers that retained the tubes’ electrical and mechanical properties over kilometer lengths–an idea that, he admitted, was “really lunatic extreme” (see “Wires of Wonder,” March 2001). Such fibers would be stronger than steel and more conductive than copper. Smalley imagined them woven into cables that could efficiently carry electricity from remote wind and solar farms to populated areas–without losing energy to heat. Pasquali, who was part of the project from the beginning and took over after Smalley’s death in 2005, acknowledges that he started out as a skeptic. “I thought that it was complete lunacy, because carbon nanotubes are not soluble in fluid–and I’m a fluid guy,” he says.
Other researchers have made macroscale fibers from dry nanotubes, pulling them from vertical arrays or spinning them like wool as they emerge from a reactor. But the individual nanotubes in these fibers don’t line up, and proper alignment is critical: tangled masses of the molecules don’t carry electricity well, and they’re not strong. Pasquali knew that nanotubes brought into solution would line up like logs floating down a river, resulting in well-ordered fibers.
The group had a breakthrough in 2004, when they reasoned that the methods used to manufacture Kevlar fibers, a component of bulletproof vests, might also work with nanotubes. Like nanotubes, the Kevlar polymer is long, thin, and difficult to dissolve in solution; the fibers are made by mixing the polymer with sulfuric acid and then shooting the solution through needles grouped like the holes in a showerhead.
The Rice researchers managed to dissolve only small amounts of nanotubes using sulfuric acid. But when they used chlorosulfonic acid–a so-called superacid–they could get high concentrations of nanotubes into solution. The tubes form a liquid crystal, in which they are already aligned–a tremendous advantage in making them into fibers.
Spinning a line
Pasquali’s group starts its spinning process with single-walled nanotubes made in a nearby lab using a process originally developed by Smalley. In a high-pressure reactor where temperatures reach 1,000 °C, carbon monoxide alights on droplets of pure iron catalyst and decomposes. The carbon atoms build up into hollow cylinders about a nanometer in diameter and a few hundred nanometers long. These nanotubes emerge from the reactor in fluffy black drifts; they’re kept in five-gallon buckets stacked to the ceiling, each holding just 200 grams.
Article Continues – http://www.technologyreview.com/computing/25100/?a=f
TR10: Light-Trapping Photovoltaics
Solar spheres: By depositing nanoparticles made of silver on thin-film photovoltaic cells, Kylie Catchpole increases the cells’ efficiency, which could make solar power more competitive. Credit: Meghan Petersen
Nanoparticles boost solar power’s prospects.
By Bob Johnstone
(from MIT Technology Review) This article is part of an annual list of what we believe are the 10 most important emerging technologies. See the full list here.
In 1995, finishing her undergraduate degree in physics, Kylie Catchpole decided to take a risk on a field that was nearly moribund: photovoltaics. “There was a sense that I might have difficulty ever being employed,” she recalls. But her gamble paid off. In 2006 Catchpole, then a postdoc, discovered something that opened the door to making thin-film solar cells significantly more efficient at converting light into electricity. It’s an advance that could help make solar power more competitive with fossil fuels.
Thin-film solar cells, which are made from semiconductor materials like amorphous silicon or cadmium telluride, are cheaper to produce than conventional solar cells, which are made from relatively thick and expensive crystalline wafers of silicon. But they are also less efficient, because if a cell is thinner than the wavelength of incoming light is long, that light is less likely to be absorbed and converted. At just a few micrometers thick, thin-film cells only weakly absorb wavelengths in the near-infrared part of the spectrum; that energy is lost. The result is that thin-film photovoltaics convert 8 to 12 percent of incoming light to electricity, versus 14 to 19 percent for crystalline silicon. Thus, larger installations are required in order to produce the same amount of electricity, limiting the number of places the technology can be used.
Catchpole, who is now a research fellow at the Australian National University in Canberra, began work on this problem in 2002 at the University of New South Wales in Sydney. “It was a case of ‘start at the beginning: can you think of a completely different way to make a solar cell?’ ” she says. “One of the things I came across was plasmonics–looking at the strange optical properties of metals.”
Plasmons are a type of wave that moves through the electrons at the surface of a metal when they are excited by incident light. Others had tried harnessing plasmonic effects to make conventional silicon photovoltaics more efficient, but no one had tried it with thin-film solar cells. Catchpole found that nanoparticles of silver she deposited on the surface of a thin-film silicon solar cell did not reflect back light that fell directly onto them, as would happen with a mirror. Instead, plasmons that formed at the particles’ surface deflected the photons so that they bounced back and forth within the cell, allowing longer wavelengths to be absorbed.
Catchpole’s experimental devices produce 30 percent more electrical current than conventional thin-film silicon cells. If Catchpole can integrate her nanoparticle technology with the processes used to mass-produce thin films commercially, it could shift the balance of technology used in solar cells. Thin-film photovoltaics could not only gain market share (they currently have just 30 percent of the market in the United States) but sustain growth in the solar industry overall.
Thus far, silicon has been losing out to cadmium telluride as the material of choice for thin-film solar cells. (First Solar, the market leader, is planning gigawatt-scale solar farms that will use cadmium telluride thin-film technology to deliver as much electricity as conventional power stations.) But tellurium is a rare material, and experts question whether the supply will support such grand ambitions. “There just isn’t enough tellurium to make a substantial difference to the way the world’s energy is produced,” says Catchpole. “Silicon is the way to go.”
Catchpole has been approached by companies, but she wants to refine the technology further before commercializing it. Meanwhile, researchers at Swinburne University of Technology in Melbourne are collaborating with Suntech Power, one of the world’s largest manufacturers of silicon solar cells, on plasmonic thin-film silicon cells of their own. The company’s plasmonic photovoltaics are expected to be ready for production within four years.
Scientists Create ‘Molecular Paper’ — Largest Two-Dimensional Polymer Crystal Self-Assembled in Water
Ron Zuckermann (left) and Ki Tae Nam with Berkeley Lab’s Molecular Foundry, have developed a ‘molecular paper’ material whose properties can be precisely tailored to control the flow of molecules, or serve as a platform for chemical and biological detection. (Credit: Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)
Two-dimensional, “sheet-like” nanostructures are commonly employed in biological systems such as cell membranes, and their unique properties have inspired interest in materials such as graphene. Now, Berkeley Lab scientists have made the largest two-dimensional polymer crystal self-assembled in water to date. This entirely new material mirrors the structural complexity of biological systems with the durable architecture needed for membranes or integration into functional devices.
These self-assembling sheets are made of peptoids, engineered polymers that can flex and fold like proteins while maintaining the robustness of synthetic materials. Each sheet is just two molecules thick yet hundreds of square micrometers in area — akin to ‘molecular paper’ large enough to be visible to the naked eye. What’s more, unlike a typical polymer, each building block in a peptoid nanosheet is encoded with structural ‘marching orders’ — suggesting its properties can be precisely tailored to an application. For example, these nanosheets could be used to control the flow of molecules, or serve as a platform for chemical and biological detection.
“Our findings bridge the gap between natural biopolymers and their synthetic counterparts, which is a fundamental problem in nanoscience,” said Ronald Zuckermann, Director of the Biological Nanostructures Facility at the Molecular Foundry. “We can now translate fundamental sequence information from proteins to a non-natural polymer, which results in a robust synthetic nanomaterial with an atomically-defined structure.”
The building blocks for peptoid polymers are cheap, readily available and generate a high yield of product, providing a huge advantage over other synthesis techniques. Zuckermann, instrumental in developing the Foundry’s one-of-a-kind robotic synthesis capabilities, worked with his team of coauthors to form libraries of peptoid materials. After screening many candidates, the team landed upon the unique combination of polymer building blocks that spontaneously formed peptoid nanosheets in water.
Zuckermann and coauthor Christian Kisielowski reached another first by using the TEAM 0.5 microscope at the National Center for Electron Microscopy (NCEM) to observe individual polymer chains within the peptoid material, confirming the precise ordering of these chains into sheets and their unprecedented stability while being bombarded with electrons during imaging.
“The design of nature-inspired, functional polymers that can be assembled into membranes of large lateral dimensions marks a new chapter for materials synthesis with direct impact on Berkeley Lab’s strategically relevant initiatives such as the Helios project or Carbon Cycle 2.0,” said NCEM’s Kisielowski. “The scientific possibilities that come with this achievement challenge our imagination, and will also help move electron microscopy toward direct imaging of soft materials.”
“This new material is a remarkable example of molecular biomimicry on many levels, and will no doubt lead to many applications in device fabrication, nanoscale synthesis and imaging,” Zuckermann added.
This research is reported in a paper appearing in the journal Nature Materials. Co-authoring the paper with Zuckermann and Kisielowski were Ki Tae Nam, Sarah Shelby, Phillip Choi, Amanda Marciel, Ritchie Chen, Li Tan, Tammy Chu, Ryan Mesch, Byoung-Chul Lee and Michael Connolly.
This work at the Molecular Foundry was supported by DOE’s Office of Science and the Defense Threat Reduction Agency.
The Molecular Foundry is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit http://nano.energy.gov.
Story Source:
Adapted from materials provided by DOE/Lawrence Berkeley National Laboratory.
Journal Reference:
- Ki Tae Nam, Sarah A. Shelby, Philip H. Choi, Amanda B. Marciel, Ritchie Chen, Li Tan, Tammy K. Chu, Ryan A. Mesch, Byoung-Chul Lee, Michael D. Connolly, Christian Kisielowski, Ronald N. Zuckermann. Free-floating ultrathin two-dimensional crystals from sequence-specific peptoid polymers. Nature Materials, 2010; DOI: 10.1038/nmat2742
http://www.sciencedaily.com/releases/2010/04/100414184222.htm
