Wednesday, October 31, 2007

Sol-gel inks produce complex shapes with nanoscale features

Graduate student Eric Duoss and Jennifer Lewis, MRL director and a Willett Faculty Scholar of EngineeringNew sol-gel inks developed by researchers at Illinois can be printed into patterns to produce three-dimensional structures of metal oxides with nanoscale features.

The ability to directly pattern functional oxides at the nanoscale opens a new avenue to functional devices. Potential applications include micro-fuel cells, photonic crystals and gas sensors.
The researchers describe the new inks in a paper accepted for publication in the journal Advanced Materials, and featured on its "Advances in Advance" website.

"Using this new family of inks, we have produced features as small as 225 nanometers," said co-author Jennifer Lewis, the Thurnauer Professor of Materials Science and Engineering and director of the university's Frederick Seitz Materials Research Laboratory (MRL). "Our goal is to get down to 100 nanometer feature sizes."

To create three-dimensional structures, the researchers use a robotic deposition process called direct-write assembly. The concentrated sol-gel ink is dispensed as a filament from a nozzle approximately 1 micron in diameter (about 100 times smaller than a human hair). The ink is dispensed while a computer-controlled micropositioner precisely directs the path. After the pattern for the first layer is complete, the nozzle is raised and another layer is deposited. This process is repeated until the desired shape is produced.

"We have opened direct ink writing to a new realm of functional materials," said graduate student Eric Duoss, the paper's lead author. "Since we print the desired functionality directly, the need for complicated templating and replicating schemes is eliminated."

Unlike previous inks, which require a liquid coagulation reservoir, the newly formulated inks are concentrated enough to rapidly solidify and maintain their shape in air, even as they span gaps in underlying layers.

"This gives us the ability to start, stop and reposition the flow of ink repeatedly, providing exquisite control over the deposition process," Duoss said. "For example, we can directly pattern defects in three-dimensional structures for use as photonic crystals."

After the structures have been assembled, they are converted to the desired functional oxide phase by heating at elevated temperature. Titanium dioxide, which possesses high refractive index and interesting electrical properties, is one material the researchers have successfully produced.

The researchers' ink design and patterning approach can be readily extended to other materials.

"There are a nearly endless variety of materials to choose from," Lewis said. "We envision having a toolbox of inks that can print at the micro- and nanoscale. These inks will be used for heterogeneous integration with other manufacturing techniques to create complex, functional devices composed of many different materials."

In addition to Lewis and Duoss, former post-doctoral researcher Mariusz Twardowski is a co-author of the paper.

Funding was provided by the U.S. Army Research Office. Part of the work was carried out in the Center for Microanalysis of Materials, which is partially supported by the U.S. Department of Energy and the University of Illinois.

Contact: James E. Kloeppel kloeppel@uiuc.edu, 217-244-1073. University of Illinois at Urbana-Champaign, Contact: Jennifer Lewis, 217/244-4973

Writer: James E. Kloeppel, physical sciences editor, Illinois News Bureau, 217/244-1073. Photo by L. Brian Stauffer.

Technorati Tags: or and and or and or President Bush Urges Congress to Pass Appropriations Bills VIDEO PODCAST and Orson Welles War ot the Worlds H.G. Wells and New force-fluorescence device measures motion previously undetectable

Tuesday, October 30, 2007

New force-fluorescence device measures motion previously undetectable

A hybrid device combining force and fluorescence developed by researchers at Illinois has made possible the accurate detection of nanometer-scale motion of biomolecules caused by pico-newton forces.

Taekjip Ha. Photo by L. Brian Stauffer“By combining single-molecule fluorescence resonance energy transfer and an optical trap, we now have a technique that can detect subtle conformational changes of a biomolecule at an extremely low applied force,” said U of I physics professor Taekjip Ha, the corresponding author of a paper to appear in the Oct. 12 issue of the journal Science.
The hybrid technique, demonstrated in the Science paper on the dynamics of Holliday junctions, is also applicable to other nucleic acid systems and their interaction with proteins and enzymes.

The Holliday junction is a four-stranded DNA structure that forms during homologous recombination – for example, when damaged DNA is repaired. The junction is named after geneticist Robin Holliday, who proposed the model of DNA-strand exchange in 1964.

To better understand the mechanisms and functions of proteins that interact with the Holliday junction, researchers must first understand the structural and dynamic properties of the junction itself.

But purely mechanical measurement techniques can not detect the tiny changes that occur in biomolecules in the regime of weak forces. Ha and colleagues have solved this problem by combining the exquisite force control of an optical trap and the precise measurement capabilities of single-molecule fluorescence resonance energy transfer.

To use single-molecule fluorescence resonance energy transfer, researchers first attach two dye molecules – one green and one red – to the molecule they want to study. Next, they excite the green dye with a laser. Some of the energy moves from the green dye to the red dye, depending upon the distance between them. The changing ratio of the two intensities indicates the relative movement of the two dyes. Therefore, by monitoring the brightness of the two dyes, the researchers can determine the motion of the molecule.

The optical trap, on the other hand, functions somewhat like the fictional tractor beam in Star Trek. In this case, a focused laser beam locks onto a microsphere attached to one end of the molecule to be studied. The optical trap can then pull on the molecule like a pair of tweezers.

“By combining the two techniques, we get the best of both worlds,” said Ha, who also is an affiliate of the university’s Institute for Genomic Biology and of the Howard Hughes Medical Institute. “Using the optical trap, we can pull on DNA strands with forces as small as half a pico-newton. Using single-molecule fluorescence resonance energy transfer, we can measure the resulting conformational changes with nanometer precision.”

By probing the dynamics of the Holliday junction in response to pulling forces in three different directions, the researchers mapped the location of the transition states and deduced the structure of the transient species present during the conformational changes.

“Based on our previous studies, we knew the Holliday junction fluctuated between two structures,” Ha said, “but how it moved from one place to the other, and what intermediates were visited along the pathway, were unknown.”

With this latest work, the researchers have deduced the pathway of the conformational flipping of the Holliday junction, and determined the intermediate structure is similar to that of a Holliday junction bound to its own processing enzyme.

“The next challenge is to obtain a timeline of movement by force, for example, due to the action of DNA processing enzymes, and correlate it with the enzyme conformational changes simultaneously measured by fluorescence,” Ha said.

With Ha, co-authors of the paper are former U of I postdoctoral research associate and lead-author Sungchul Hohng (now at Seoul National University); physics professor Klaus Schulten; graduate students Ruobo Zhou, Michelle Nahas and Jin Yu; and molecular biology professor David M. J. Lilley at the University of Dundee, UK.

The work was funded by the National Science Foundation and the National Institutes of Health.

Contact: Taekjip Ha, Department of Physics, 217/265-0717.

Writer: James E. Kloeppel, physical sciences editor, Illinois News Bureau, 217/244-1073.

Photo by L. Brian Stauffer.

Contact: James E. Kloeppel, Physical Sciences Editor. kloeppel@uiuc.edu. 217-244-1073. University of Illinois at Urbana-Champaign

Technorati Tags: or and and or and or Tom Tancredo's Retirement from Congress and Hudson Hornet and Rutgers physicist earns Packard Foundation Science and Engineering Fellowship

Monday, October 29, 2007

Rutgers physicist earns Packard Foundation Science and Engineering Fellowship

Five-year, $625,000 Award is First for Rutgers; One of Two Awarded This Year in Physics

Emil Yuzbashyan Photo by Carl BleschNew Brunswick, N.J. – Rutgers physicist Emil Yuzbashyan has received a Packard Foundation Fellowship for Science and Engineering, which provides $625,000 in research funding for five years. This marks the first time the Packard Foundation has awarded this coveted fellowship to a Rutgers University professor.

Yuzbashyan is among 20 fellows that the foundation selected from nominations at 50 of the nation’s top private and public research universities.
He is also one of two physics faculty selected for this year’s fellowships. Recipients are in the first three years of their faculty careers and have shown exceptional creativity in individual research.

“Having one of our faculty win this award is a landmark for Rutgers,” said Torgny Gustafsson, chair of the university’s physics and astronomy department. “This is an extremely competitive award – only 26 universities have hosted Packard fellows in physics during the award’s 19-year lifetime. We are pleased to be a part of that elite group.”

Yuzbashyan, who joined Rutgers in 2004 after earning his doctorate in physics from Princeton University, is studying properties of matter at temperatures close to absolute zero – the point where all motion ceases. Particles at these temperatures interact with each other in unusual ways; understanding those interactions could promote powerful new technologies such as quantum devices and superconductivity.

“Past recipients of Packard fellowships have had successful careers and become well known in their fields,” said Yuzbashyan. “The fellowship will help me build a skilled team of doctoral students, postdoctoral research fellows and visiting scientists to pursue this research and collaborate with others doing related work worldwide.”

Yuzbashyan’s research is in a branch of physics known as condensed matter physics, which deals with the physical properties of solid and liquid matter. He has recently developed a new theory related to superfluidity, or how a liquid cooled to near absolute zero can flow endlessly in a closed loop without any outside sources of energy to sustain that motion.

“Superfluidity was one of the biggest problems in physics – it took scientists many decades to solve,” he noted. “But their description was for situations where the superfluid is in equilibrium or in some way close to it; that is, where the unusual states of matter that we see near absolute zero are constant in time.”

Yuzbashyan’s latest research describes behavior of a superfluid that is far from being at equilibrium, or where states of matter are in the process of changing. In such systems, he and his colleagues predict they will see new states of matter that have not yet been observed. Future work will involve conducting experiments to create these environments and verify the matter and behaviors Yuzbashyan has proposed.

His other research interests include study of ultracold atoms and nanoparticles that exhibit atomic-level behaviors known as quantum properties.

A native of Armenia, Yuzbashyan earned his Master of Science degree from the Moscow Institute of Physics and Technology in 1995 and later worked at Russia’s Joint Institute for Nuclear Research. He came to the United States in 1998 to pursue his doctoral studies.

Yuzbashyan lives in Plainsboro, N.J.

Contact: Carl Blesch cblesch@ur.rutgers.edu 732-932-7084 x616. Rutgers, the State University of New Jersey

Technorati Tags: or and and or and or In human grid, we're the cogs and The Crab Nebula and CU researchers shed light on light-emitting nanodevice

Sunday, October 28, 2007

CU researchers shed light on light-emitting nanodevice

Caption: Top view of the ruthenium tris-bipyridine light-emitting device created by Cornell researchers. The ruthenium metal complex is represented by red spheres, and counter ions are represented by green spheres. The material is sandwiched between two gold electrodes. Also visible is the probe of the electron force microscope used to measure the electric field of the device. Credit: Cornell University. Usage Restrictions: None.An interdisciplinary team of Cornell nanotechnology researchers has unraveled some of the fundamental physics of a material that holds promise for light-emitting, flexible semiconductors.

The discovery, which involved years of perfecting a technique for building a specific type of light-emitting device, is reported in the Sept. 30 online publication of the journal Nature Materials.
The interdisciplinary team had long studied the molecular semiconductor ruthenium tris-bipyridine. For many reasons, including its ability to allow electrons and holes (spaces where electrons were before they moved) to pass through it easily, the material has the potential to be used for flexible light-emitting devices. Sensing, microscopy and flat-panel displays are among its possible applications.

The researchers set out to understand the fundamental physics of the material -- that is, what happens when it encounters an electric field, both at the interfaces and inside the film. By fabricating a device out of the ruthenium metal complex that was spin-coated onto an insulating substrate with pre-patterned gold electrodes, the scientists were able to use electron force microscopy to measure directly the electric field of the device.

A long-standing question, according to George G. Malliaras, associate professor of materials science and engineering, director of the Cornell NanoScale Science and Technology Facility and one of the co-principal investigators, was whether an electric field, when applied to the material, is concentrated at the interfaces or in the bulk of the film.

The researchers discovered that it was at the interfaces -- two gold metal electrodes sandwiching the ruthenium complex film -- which was a huge step forward in knowing how to build and engineer future devices.

"So when you apply the electric field, ions in the material move about, and that creates the electric fields at the interfaces," Malliaras explained.

Essential to the effort was the ability to pattern the ruthenium complex using photolithography, a technique not normally used with such materials and one that took the researchers more than three years to perfect, using the knowledge of experts in nanofabrication, materials and chemistry.

The patterning worked by laying down a gold electrode and a polymer called parylene. By depositing the ruthenium complex on top of the parylene layer and filling in an etched gap between the gold electrodes, the researchers were then able to peel the parylene material off mechanically, leaving a perfect device.

Ruthenium tris-bipyridine has energy levels well suited for efficient light emission of about 600 nanometers, said Héctor D. Abruña, the E.M. Chamot Professor of Chemistry, and a principal co-investigator. The material, which has interested scientists for many years, is ideal for its stability in multiple states of oxidation, which, in turn, allows it to serve as a good electron and hole transporter. This means that a single-layer device can be made, simplifying the manufacturing process.

"It's not fabulous, but it has a reasonable emission efficiency," Abruña said. "One of the drawbacks is it has certain instabilities, but we have managed to mitigate most of them."

Among the other authors were co-principal investigators Harold G. Craighead, the C.W. Lake Jr. Professor of Engineering, and John A. Marohn, associate professor of chemistry and chemical biology. ###

Contact: Press Relations Office. pressoffice@cornell.edu, 607-255-6074. Cornell University News Service

Technorati Tags: or and and or and or Presidential Podcast 10/27/07 and Happy Halloween Banners and Taming tiny, unruly waves for nano optics

Saturday, October 27, 2007

Taming tiny, unruly waves for nano optics

Waves of electromagnetic energy passing through a vacuum between two plates of silicon carbide just 100 nanometers apart, one at an elevated temperature. The lines represent the energy stream, bending the light as it is pushed through the small gap.Waves of electromagnetic energy passing through a vacuum between two plates of silicon carbide just 100 nanometers apart, one at an elevated temperature. The lines represent the energy stream, bending the light as it is pushed through the small gap.
Nanoscale devices present a unique challenge to any optical technology — there’s just not enough room for light to travel in a straight line.

On the nanoscale, energy may be produced by radiating photons of light between two surfaces very close together (sometimes as close as 10 nanometers), smaller than the wavelength of the light. Light behaves much differently on the nanoscale as its wavelength is interrupted, producing unstable waves called evanescent waves. The direction of these unpredictable waves can’t be calculated, so researchers face the daunting task of designing nanotechnologies to work with the tiny, yet potentially useful waves of light.

Researchers at Georgia Tech have discovered a way to predict the behavior of these unruly waves of light during nanoscale radiation heat transfer, opening the door to the design of a spectrum of new nanodevices (or NEMS) and nanotechnologies, including solar thermal energy technologies. Their findings were featured on the cover of the Oct. 8 issue of Applied Physics Letters.

“This discovery gives us the fundamental information to determine things like how far apart plates should be and what size they should be when designing a technology that uses nanoscale radiation heat transfer,” said Zhuomin Zhang, a lead researcher on the project and a professor in the Woodruff School of Mechanical Engineering. “Understanding the behavior of light at this scale is the key to designing technologies to take advantage of the unique capabilities of this phenomenon.”

The Georgia Tech research team set out to study evanescent waves in nanoscale radiation energy transfer (between two very close surfaces at different temperatures by means of thermal radiation). Because the direction of evanescent waves is seemingly unknowable (an imaginary value) in physics terms, Zhang’s group instead decided to follow the direction of the electromagnetic energy flow (also known as a Poynting vector) to predict behavior rather than the direction of the photons.

“We’re using classic electrodynamics to explain the behavior of the waves, not quantum mechanics,” Zhang said. “We’re predicting the energy propagation — and not the actual movement — of the photons.”

The challenge is that electrodynamics work differently on the nanoscale and the Georgia Tech team would need to pinpoint those differences. Planck’s law, a more than 100-year-old theory about how electromagnetic waves radiate, does not apply on the nanoscale due to fact that the space between surfaces is smaller than a wavelength.

The Georgia Tech team observed that instead of normal straight line radiation, the light was bending as protons tunneled through the vacuum in between the two surfaces just nanometers apart. The team also noticed that the evanescent waves were separating during this thermal process, allowing them to visualize and predict the energy path of the waves.

Understanding the behavior of such waves is critical to the design of many devices that use nanotechnology, including near-field thermophotovoltaic systems, nanoscale imaging based on thermal radiation scanning tunneling microscopy and scanning photon-tunneling microscopy, said Zhang.

Related Links:Contact: Megan McRainey, megan.mcrainey@icpa.gatech.edu, 404-894-6016. Georgia Institute of Technology

The Georgia Institute of Technology is one of the nation's premiere research universities. Ranked ninth among U.S. News & World Report's top public universities, Georgia Tech educates more than 17,000 students every year through its Colleges of Architecture, Computing, Engineering, Liberal Arts, Management and Sciences. Tech maintains a diverse campus and is among the nation's top producers of women and African-American engineers.

The Institute offers research opportunities to both undergraduate and graduate students and is home to more than 100 interdisciplinary units plus the Georgia Tech Research Institute. During the 2004-2005 academic year, Georgia Tech reached $357 million in new research award funding. The Institute also maintains an international presence with campuses in France and Singapore and partnerships throughout the world.

Technorati Tags: or and and or and or President Bush Governor Schwarzenegger PODCAST VIDEO and Native American Heritage Geronimo and Developing a modular, nanoparticle drug delivery system

Friday, October 26, 2007

Developing a modular, nanoparticle drug delivery system

Caption: Eva Harth in her laboratory. Credit: Neil Brake. Usage Restrictions: None.There are two aspects to creating an effective drug: finding a chemical compound that has the desired biological effect and minimal side-effects and then delivering it to the right place in the body for it to do its job.

With the support from a $478,000, five-year CAREER award from the National Science Foundation, Eva Harth is tackling the second part of this problem. She is creating a modular, multi-functional drug delivery system that promises simultaneously to enhance the effectiveness and reduce undesirable side-effects of a number of different drugs.
(NSF’s Faculty Early Career Development awards are the agency’s most prestigious honor for junior faculty members and are given to individuals judged most likely to become the academic leaders of the 21st century.)

Harth, who is an assistant professor of chemistry at Vanderbilt University, has created a “nanosponge” specially designed to carry large numbers of drug molecules. She has also discovered a “molecular transporter” that, when attached to the nanosponge, carries it and its cargo across biological barriers into specific intracellular compartments, which are very difficult places for most drugs to reach. She has shown that her system can reach another difficult target: the brain. Experiments have shown that it can pass through the brain-blood barrier. In addition, she has: successfully attached a special “targeting unit” that delivers drugs to the surface of tumors in the lungs, brain and spinal cord and even developed a “light kit” for her delivery system – fluorescent tags that researchers can use to monitor where it goes.
Harth has taken a different approach from other researchers working on nanotechnology for drug development. Instead of trying to encapsulate drugs in nanoscale containers, she decided to create a nanoparticle that had a large number of surface sites where drug molecules could be attached. To do so, she adopted a method that uses extensive internal cross-linking to scrunch a long, linear molecule into a sphere about 10 nanometers in diameter, about the size of a protein. Nanoparticles like this are called nanosponges.modular, multifunctional drug delivery system.
“We can really load this up with a large number of drug molecules,” she says.
Heidi HammWorking with Heidi Hamm, the Earl W. Sutherland Jr. Professor of Pharmacology at Vanderbilt, Harth synthesized a dendritic molecule with the ability to slip through cell membranes and reach the cell nucleus. They figured out how to attach this “transporter” to her nanoparticle and showed that the transporter can pull the nanoparticle after it into cellular compartments. They also demonstrated that the transporter can deliver large molecules – specifically peptides and proteins – into specific sub-cellular locations.
“Peptides and proteins can act as drugs, just like smaller molecules,” Harth says. “However, there is not much activity in this area because people haven’t had a method for getting them into cells. Now that there is a way to do it, but that may change.”

Hamm studies G proteins, arguably the most important signaling molecules in the cell. Scientists think that many diseases, including diabetes and certain forms of pituitary cancer, are caused by malfunctioning G proteins. She and Harth are collaborating on using the transporter to deliver peptides produced by G proteins that disrupt signaling pathways.

“Eva’s methods for drug delivery are very novel and versatile and can be adapted to delivery of proteins, peptides, DNA and smaller chemical compounds like most drugs. The breadth of applications makes her technology very powerful,” Hamm says.
The chemist is also collaborating with Dennis E. Hallahan, professor of radiation oncology at Vanderbilt, to apply the drug delivery system to fighting cancer. Hallahan’s lab had identified a molecule that targets a surface feature on lung carcinomas. Harth took the molecule, improved it, attached it to her nanoparticle and the two of them determined that the combination is capable of delivering drugs to the surface of lung tumors.Dennis E. Hallahan, professor of radiation oncology at Vanderbilt
She is now working with Hallahan to adapt her delivery system to carry cisplatinum, a traditional chemotherapy agent that is used to treat a number of different kinds of cancer but is highly toxic and has a number of unpleasant side effects.

By delivering the anti-cancer agent directly to the cancerous tissues, Eva’s system decreases the adverse effects on other tissues and increases its potency by delivering a higher concentration of the drug directly on the cancer, Hallahan explains.

“The people in my lab have tried at a number of different drug delivery systems and Eva’s works the best of those we’ve looked at,” Hallahan says.

Vanderbilt is applying for two patents on the system.

Contact: David F. Salisbury david.salisbury@vanderbilt.edu, 615-343-6803. Vanderbilt University

Technorati Tags: or and and or and or Governor Arnold Schwarzenegger Claire Shipman VIDEO and Native American Heritage Sitting Bull and Peter Cummings to receive the 2007 AIChE Nanoscale Science and Engineering Forum Award

Thursday, October 25, 2007

Peter Cummings to receive the 2007 AIChE Nanoscale Science and Engineering Forum Award

Peter Cummings, John R. Hall Professor of Chemical Engineering at Vanderbilt, will receive the 2007 American Institute of Chemical Engineers (AlChE) Nanoscale Science and Engineering Forum Award at the institute’s annual meeting in November.

The award recognizes outstanding contributions to the advancement of nanoscale science and engineering in the field of chemical engineering through scholarship, education or service.
Cummings is being honored "for outstanding research accomplishments and national leadership in computational nanoscience," according to the award citation. Nanoscience refers to the study of matter as small as one billionth of a meter.

As principal scientist at the Oak Ridge National Laboratory’s Center for Nanophase Materials Sciences and director of the laboratory’s Nanomaterials Theory Institute, Cummings oversees a team of scientists and engineers working to develop new materials to be used in medicine, electronics, and a wide variety of industrial applications. Since joining the Vanderbilt engineering faculty in 2002, his achievements include developing the leading model for water used in molecular-level computer simulations and participation in computer modeling to predict how individual cancer cells are likely to spread through the body.

Cummings has been a strong advocate for the development of new multiscale computer modeling techniques to support advances in nanoscience and to make nanotechnology a practical reality. His areas of specialization include nanotribology, molecular electronics, and hybrid organic-inorganic nanocomposites.

He will touch on all of these topics while delivering the Nanoscale Science and Engineering Award Lecture during the AIChE Annual Meeting, Nov. 4-9, in Salt Lake City, Utah. His talk is titled, “Computational and Theoretical Nanoscience – Emerging Tools for Nanoscience and Nanotechnology.”

Cummings was also the recipient of AIChE’s Alpha Chi Sigma Award in 1998 recognizing the most outstanding research achievement in chemical engineering over the previous decade and was elected a Fellow of the American Physical Society in 2006.

Contact: David F. Salisbury, david.salisbury@vanderbilt.edu 615-343-6803, Vanderbilt University

Technorati Tags: or and and or and or Bloodrocuted and Native American Heritage Hollow Horn Bear and Nanofabrication method paves way for new optical devices

Wednesday, October 24, 2007

Nanofabrication method paves way for new optical devices

Nanofabrication method paves way for new optical devicesAn innovative and inexpensive way of making nanomaterials on a large scale has resulted in novel forms of advanced materials that pave the way for exceptional and unexpected optical properties. The new fabrication technique, known as soft lithography, or SIL, offers many significant advantages over existing techniques, including the ability to scale-up the manufacturing process to produce devices in large quantities.
The research, funded by the National Science Foundation (NSF) and led by Teri Odom of Northwestern University, appears as the cover story in the September 2007 issue of Nature Nanotechnology.

The optical nanomaterials in this research are called 'plasmonic metamaterials' because their unique physical properties originate from shape and structure rather than material composition only. Two examples of metamaterials in the natural world are peacock feathers and butterfly wings. Their brightly colored patterns are due to structural variations at the hundreds of nanometers level, which cause them to absorb or reflect light.

Through the development of a new nanomanufacturing technique, Odom and her co-workers have succeeded in making gold films with virtually infinite arrays of perforations as small as 100 nanometers--500-1000 times smaller than a human hair. On a magnified scale, these perforated gold films look like Swiss cheese except the perforations are well-ordered and can spread over macroscale distances. The researchers' ability to make these optical metamaterials inexpensively and on large wafers or sheets is what sets this work apart from other techniques.

"One of the biggest problems with nanomaterials has always been their 'scalability,'" Odom said. "It's been very difficult or prohibitively expensive to pattern them over areas larger than about one square millimeter. This research is exciting not only because it demonstrates a new type of patterning technique that is cheap, but also one that can produce very high quality optical materials with interesting properties."

For example, if the perforations or holes are patterned into microscale "patches," they show dramatically different transmission behavior of light compared to an infinite array of holes. The patches appear to focus light while the infinite arrays do not.

Moreover, their optical transmission can be altered simply by changing the geometry of perforations rather than having to "cook" a new composition of materials. This feature makes them very attractive in terms of tuning their behavior to a given need with ease. These materials can also be superior as optical sensors, and they open the possibility of ultra-small sources of light. Furthermore, given their precise organization, they can serve as templates for making their own clones or for making other ordered structures at the nanoscale, such as arrays of nanoparticles.

"The work of Professor Odom is an outcome of a grant mechanism at NSF called Small Grants for Exploratory Research that is aimed at exploring high-risk, high-payoff ideas that are potentially transformative to the field said Harsh Deep Chopra, director of NSF's Metals Program in the Division of Materials Research. "The early results are encouraging and suggest the potential for a new generation of optical devices." This work is supported both the Metals Program and the Materials Research Science and Engineering Centers Program in the Division of Materials Research at NSF.

-NSF-

Media Contacts: Diane E. Banegas, NSF (703) 292-8070 dbanegas@nsf.gov Contact: Megan Fellman, fellman@northwestern.edu 847-491-3115, Northwestern University

Photo Credit: Reprinted by permission from Macmillan Publishers Ltd: "Multiscale patterning of plasmonic metamaterials," Joel Henzie, Min Hyung Lee and Teri W. Odom, Nature Nanotechnology 2, 549 - 554 (2007

The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering, with an annual budget of $5.92 billion. NSF funds reach all 50 states through grants to over 1,700 universities and institutions. Each year, NSF receives about 42,000 competitive requests for funding, and makes over 10,000 new funding awards. The NSF also awards over $400 million in professional and service contracts yearly.

Technorati Tags: or and and or and or President Bush Visits National Defense University VIDEO and California Wild Fires and Argonne researcher studies what makes quantum dots blink

Tuesday, October 23, 2007

Argonne researcher studies what makes quantum dots blink

Caption: Matthew Pelton of Argonne's Center for Nanoscale Materials adjusts a green laser used to monitor the sporadic blinking of quantum dots. Credit: Jason Smith. Usage Restrictions: None.In order to learn more about the origins of quantum dot blinking, researchers from the U.S. Department of Energy's Argonne National Laboratory, the University of Chicago and the California Institute of Technology have developed a method to characterize it on faster time scales than have previously been accessed. High Resolution Image
Nanocrystals of semiconductor material, also known as quantum dots, are being intensively investigated for applications such as light-emitting diodes, solid-state lighting, lasers, and solar cells. They are also already being applied as fluorescent labels for biological imaging, providing several advantages over the molecular dyes typically used, including a wider range of emitted colors and much greater stability.

Quantum dots have great promise as light-emitting materials, because the wavelength, or color, of light that the quantum dots give off can be very widely tuned simply by changing the size of the nanoparticles. If a single dot is observed under a microscope, it can be seen to randomly switch between bright and dark states. This flickering, or blinking, behavior has been widely studied, and it has been found that a single dot can blink off for times that can vary between microseconds and several minutes. The causes of the blinking, though, remain the subject of intense study.

The methods developed by Matt Pelton of Argonne's Center for Nanoscale Materials and his team of collaborators has revealed a previously unobserved change in the blinking behavior on time scales less than a few microseconds. This observation is consistent with the predictions of a model for quantum-dot blinking previously developed by Nobel Laureate Rudolph Marcus, contributor to this research, and his co-workers. In this model, the blinking is controlled by the random fluctuation of energy levels in the quantum dot relative to the energies of trap states on the surface of the nanocrystal or in the nearby environment.

The results of this research provide new insight into the mechanism of quantum-dot blinking, and should help in the development of methods to control and suppress blinking. Detailed results of this work have been published in a paper in the Proceedings of the National Academy of Sciences.

Argonne's Center for Nanoscale Materials work for this research was funded by the U.S. Department of Energy's Office of Basic Energy Science.

Argonne National Laboratory, a renowned R&D center, brings the world's brightest scientists and engineers together to find exciting and creative new solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America 's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

Contact: Sylvia Carson scarson@anl.gov 630-252-5510. DOE/Argonne National Laboratory

Technorati Tags: or and and or and or Republican Debate Orlando Florida 10/21/07 VIDEO and Native American Heritage Month Calling a Moose and New plastic is strong as steel, transparent

Monday, October 22, 2007

New plastic is strong as steel, transparent

U-M research: New plastic is strong as steel, transparent

ANN ARBOR, Mich.—By mimicking a brick-and-mortar molecular structure found in seashells, University of Michigan researchers created a composite plastic that's as strong as steel but lighter and transparent.

It's made of layers of clay nanosheets and a water-soluble polymer that shares chemistry with white glue.

 Nicholas A. Kotov, Engineering professor.Engineering professor Nicholas Kotov almost dubbed it "plastic steel," but the new material isn't quite stretchy enough to earn that name. Nevertheless, he says its further development could lead to lighter, stronger armor for soldiers or police and their vehicles. It could also be used in microelectromechanical devices, microfluidics, biomedical sensors and valves and unmanned aircraft.
Kotov and other U-M faculty members are authors of a paper on this composite material, "Ultrastrong and Stiff Layered Polymer Nanocomposites," published in the Oct. 5 edition of Science.

The scientists solved a problem that has confounded engineers and scientists for decades: Individual nano-size building blocks such as nanotubes, nanosheets and nanorods are ultrastrong. But larger materials made out of bonded nano-size building blocks were comparatively weak. Until now.

"When you tried to build something you can hold in your arms, scientists had difficulties transferring the strength of individual nanosheets or nanotubes to the entire material," Kotov said. "We've demonstrated that one can achieve almost ideal transfer of stress between nanosheets and a polymer matrix."

The researchers created this new composite plastic with a machine they developed that builds materials one nanoscale layer after another.

The robotic machine consists of an arm that hovers over a wheel of vials of different liquids. In this case, the arm held a piece of glass about the size of a stick of gum on which it built the new material. The arm dipped the glass into the glue-like polymer solution and then into a liquid that was a dispersion of clay nanosheets. After those layers dried, the process repeated. It took 300 layers of each the glue-like polymer and the clay nanosheets to create a piece of this material as thick as a piece of plastic wrap.

Mother of pearl, the iridescent lining of mussel and oyster shells, is built layer-by-layer like this. It's one of the toughest natural mineral-based materials.

The glue-like polymer used in this experiment, which is polyvinyl alcohol, was as important as the layer-by-layer assembly process. The structure of the "nanoglue" and the clay nanosheets allowed the layers to form cooperative hydrogen bonds, which gives rise to what Kotov called "the Velcro effect." Such bonds, if broken, can reform easily in a new place.

The Velcro effect is one reason the material is so strong. Another is the arrangement of the nanosheets. They're stacked like bricks, in an alternating pattern.

"When you have a brick-and-mortar structure, any cracks are blunted by each interface," Kotov explained. "It's hard to replicate with nanoscale building blocks on a large scale, but that's what we've achieved."
mechanical engineering professor Ellen ArrudaCollaborators include: mechanical engineering professor Ellen Arruda; aerospace engineering professor Anthony Waas; chemical, materials science and biomedical engineering professor Joerg Lahann; and chemistry professor Ayyalusamy Ramamoorthy. Kotov is a professor of chemical engineering, materials science and engineering, and biomedical engineering.
The nanomechanical behavior of these materials is being modeled by professor Arruda's group; Waas and his group are working on nanomechanical behavior and applications in aviation.
The University of Michigan College of Engineering, which is ranked among the top engineering schools in the country. Michigan Engineering boasts one of the largest engineering research budgets of any public university, at more than $130 million. Michigan Engineering has 11 departments and an NSF Engineering Research Center. Within those departments and the center, there is a special emphasis on research in three emerging areas: nanotechnology and integrated microsystems; cellular and molecular biotechnology;Anthony Waas; aerospace engineering professor.
and information technology. Michigan Engineering is seeking to raise $110 million for capital building projects and program support in these areas to further research discovery. Michigan Engineering's goal is to advance academic scholarship and market cutting-edge research to improve public health and well-being.

Related Links: Contact: Nicole Casal Moore, ncmoore@umich.edu 734-647-1838. University of Michigan

Technorati Tags: or and and or and or New viruses to treat MRSA Methicillin-resistant Staphylococcus aureus and Native American Heritage Month Maricopa Tribe and Nanotube forests grown on silicon chips for future computers, electronics

Sunday, October 21, 2007

Nanotube forests grown on silicon chips for future computers, electronics

Nanotube forests grown on silicon chips for future computers, electronics, Credit: David UmbergerMechanical engineering doctoral student Baratunde A. Cola, from left, looks through a view port in a plasma-enhanced chemical vapor deposition instrument while postdoctoral research fellow Placidus Amama adjusts settings. The two engineers recently have shown how to grow forests of tiny cylinders called carbon nanotubes
onto the surfaces of computer chips to enhance the flow of heat at a critical point where the chips connect to cooling devices called heat sinks. The carpetlike growth of nanotubes has been shown to outperform conventional "thermal interface materials." The research is based at the Birck Nanotechnology Center in Discovery Park at Purdue. Credit: David Umberger Usage Restrictions: None.

WEST LAFAYETTE, Ind. - Engineers have shown how to grow forests of tiny cylinders called carbon nanotubes onto the surfaces of computer chips to enhance the flow of heat at a critical point where the chips connect to cooling devices called heat sinks.

The carpetlike growth of nanotubes has been shown to outperform conventional "thermal interface materials." Like those materials, the nanotube layer does not require elaborate clean-room environments, representing a possible low-cost manufacturing approach to keep future chips from overheating and reduce the size of cooling systems, said Placidus B. Amama, a postdoctoral research associate at the Birck Nanotechnology Center in Purdue's Discovery Park.

Researchers are trying to develop new types of thermal interface materials that conduct heat more efficiently than conventional materials, improving overall performance and helping to meet cooling needs of future chips that will produce more heat than current microprocessors. The materials, which are sandwiched between silicon chips and the metal heat sinks, fill gaps and irregularities between the chip and metal surfaces to enhance heat flow between the two.

The method developed by the Purdue researchers enables them to create a nanotube interface that conforms to a heat sink's uneven surface, conducting heat with less resistance than comparable interface materials currently in use by industry, said doctoral student Baratunde A. Cola.

Findings were detailed in a research paper that appeared in September's issue of the journal Nanotechnology. The paper was written by Amama; Cola; Timothy D. Sands, director of the Birck Nanotechnology Center and the Basil S. Turner Professor of Materials Engineering and Electrical and Computer Engineering; and Xianfan Xu and Timothy S. Fisher, both professors of mechanical engineering.

Better thermal interface materials are needed either to test computer chips in manufacturing or to keep chips cooler during operation in commercial products.

"In a personal computer, laptop and portable electronics, the better your thermal interface material, the smaller the heat sink and overall chip-cooling systems have to be," Cola said.

Heat sinks are structures that usually contain an array of fins to increase surface contact with the air and improve heat dissipation, and a fan often also is used to blow air over the devices to cool chips.

Conventional thermal interface materials include greases, waxes and a foil made of a metal called indium. All of these materials, however, have drawbacks. The greases don't last many cycles of repeatedly testing chips on the assembly line. The indium foil doesn't make good enough contact for optimum heat transfer, Fisher said.

The Purdue researchers created templates from branching molecules called dendrimers, forming these templates on a silicon surface. Then, metal catalyst particles that are needed to grow the nanotubes were deposited inside cavities between the dendrimer branches. Heat was then applied to the silicon chip, burning away the polymer and leaving behind only the metal catalyst particles.

The engineers then placed the catalyst particle-laden silicon inside a chamber and exposed it to methane gas. Microwave energy was applied to break down the methane, which contains carbon. The catalyst particles prompted the nanotubes to assemble from carbon originating in the methane, and the tubes then grew vertically from the surface of the silicon chip.

"The dendrimer is a vehicle to deliver the cargo of catalyst particles, making it possible for us to seed the carbon nanotube growth right on the substrate," Amama said. "We are able to control the particle size - what ultimately determines the diameters of the tubes - and we also have control over the density, or the thickness of this forest of nanotubes. The density, quality and diameter are key parameters in controlling the heat-transfer properties."

The catalyst particles are made of "transition metals," such as iron, cobalt, nickel or palladium. Because the catalyst particles are about 10 nanometers in diameter, they allow the formation of tubes of similar diameter.

The branching dendrites are tipped with molecules called amines, which act as handles to stick to the silicon surface.

"This is important because for heat-transfer applications, you want the nanotubes to be well-anchored," Amama said.

Researchers usually produce carbon nanotubes separately and then attach them to the silicon chips or mix them with a polymer and then apply them as a paste.

"Our direct growth approach, however, addresses the critical heat-flow path, which is between the chip surface and the nanotubes themselves," Fisher said. "Without this direct connection, the thermal performance suffers greatly."

Because the dendrimers have a uniform composition and structure, the researchers were able to control the distribution and density of catalyst particles.

The research team also has been able to control the number of "defect sites" in the lattice of carbon atoms making up the tubes, creating tubes that are more flexible. This increased flexibility causes the nanotube forests to conform to the surface of the heat sink, making for better contact and improved heat conduction.

"The tubes bend like toothbrush bristles, and they stick into the gaps and make a lot of real contact," Cola said.

The carbon nanotubes were grown using a technique called microwave plasma chemical vapor deposition, a relatively inexpensive method for manufacturing a thermal-interface material made of carbon nanotubes, Fisher said.

"The plasma deposition approach allows us great flexibility in controlling the growth environment and has enabled us to grow carbon nanotube arrays over a broad range of substrate temperatures," Fisher said. ###

The research has been funded by NASA through the Institute for Nanoelectronics and Computing, based at Purdue's Discovery Park. Cola also received support through a fellowship from Intel Corp. and Purdue.

Sources: Related Web sites: Contact: Emil Venere. venere@purdue.edu. 765-494-4709. Purdue University

Technorati Tags: or and and or and or Presidential Podcast 10/20/07 and Native American Heritage Month Apache Still Life and Quantum Device Traps, Detects and Manipulates the Spin of Single Electrons

Saturday, October 20, 2007

Quantum Device Traps, Detects and Manipulates the Spin of Single Electrons

A semiconductor developed by UB engineers provides a novel way to trap, detect and manipulate electron spin.BUFFALO, N.Y. -- A novel device, developed by a team led by University at Buffalo engineers, simply and conveniently traps, detects and manipulates the single spin of an electron, overcoming some major obstacles that have prevented progress toward spintronics and spin-based quantum computing.
Published online this week in Physical Review Letters, the research paper in PDF format brings closer to reality electronic devices based on the use of single spins and their promise of low-power/high-performance computing.

"The task of manipulating the spin of single electrons is a hugely daunting technological challenge that has the potential, if overcome, to open up new paradigms of nanoelectronics," said Jonathan P. Bird, Ph.D., professor of electrical engineering in the UB School of Engineering and Applied Sciences and principal investigator on the project. "In this paper, we demonstrate a novel approach that allows us to easily trap, manipulate and detect single-electron spins, in a scheme that has the potential to be scaled up in the future into dense, integrated circuits."

While several groups have recently reported the trapping of a single spin, they all have done so using quantum dots, nanoscale semiconductors that can only demonstrate spin trapping in extremely cold temperatures, below 1 degree Kelvin.

The cooling of devices or computers to that temperature is not routinely achievable, Bird said, and it makes systems far more sensitive to interference.

The UB group, by contrast, has trapped and detected spin at temperatures of about 20 degrees Kelvin, a level that Bird says should allow for the development of a viable technology, based on this approach.

In addition, the system they developed requires relatively few logic gates, the components in semiconductors that control electron flow, making scalability to complex integrated circuits very feasible.

The UB researchers achieved success through their innovative use of quantum point contacts: narrow, nanoscale constrictions that control the flow of electrical charge between two conducting regions of a semiconductor.

"It was recently predicted that it should be possible to use these constrictions to trap single spins," said Bird. "In this paper, we provide evidence that such trapping can, indeed, be achieved with quantum point contacts and that it may also be manipulated electrically."

The system they developed steers the electrical current in a semiconductor by selectively applying voltage to metallic gates that are fabricated on its surface.

These gates have a nanoscale gap between them, Bird explained, and it is in this gap where the quantum point contact forms when voltage is applied to them.

By varying the voltage applied to the gates, the width of this constriction can be squeezed continuously, until it eventually closes completely, he said.

"As we increase the charge on the gates, this begins to close that gap," explained Bird, "allowing fewer and fewer electrons to pass through until eventually they all stop going through. As we squeeze off the channel, just before the gap closes completely, we can detect the trapping of the last electron in the channel and its spin."

The trapping of spin in that instant is detected as a change in the electrical current flowing through the other half of the device, he explained.

"One region of the device is sensitive to what happens in the other region," he said.

Now that the UB researchers have trapped and detected single spin, the next step is to work on trapping and detecting two or more spins that can communicate with each other, a prerequisite for spintronics and quantum computing.

Co-authors on the paper are Youngsoo Yoon, Ph.D., a UB doctoral student in electrical engineering; L. Mourokh of Queens College and the College of Staten Island of the City University of New York; T. Morimoto, N. Aoki and Y. Ochiai of Chiba University in Japan; and J. L. Reno of Sandia National Laboratories.

The research was funded by the U.S. Department of Energy. Bird, who also has received funding from the UB Office of the Vice President for Research, was recruited to UB with a faculty recruitment grant from the New York State Office of Science, Technology and Academic Outreach (NYSTAR).

The University at Buffalo is a premier research-intensive public university, the largest and most comprehensive campus in the State University of New York. UB's more than 28,000 students pursue their academic interests through more than 300 undergraduate, graduate and professional degree programs. Founded in 1846, the University at Buffalo is a member of the Association of American Universities.

Contact: Ellen Goldbaum goldbaum@buffalo.edu 716-645-5000 x1415 University at Buffalo

Technorati Tags: or and and or and or White House Press Briefing by Dana Perino 10/19/07 VIDEO PODCAST and Native American Heritage Month Two Tepees and Using nanotubes to detect and repair cracks in aircraft wings, other structures

Friday, October 19, 2007

Using nanotubes to detect and repair cracks in aircraft wings, other structures

Using nanotubes to detect and repair cracks in aircraft wings, other structures, New technology enables real-time diagnostics and on-site repair

Caption: Professor Nikhil Koratkar has developed a new method to use carbon nanotubes for both detecting and repairing tiny cracks in nearly any polymer structure. In this image, carbon nanotubes are randomly dispersed in an epoxy resin, which can be molded into different structures. By infusing the polymer with electrically conductive carbon nanotubes and monitoring the electrical resistance at different points in the structure, he can pinpoint the location and length of even the tiniest stress-induced crack. Once a crack is located, Kotakar can then send a short electrical charge to the area in order to heat up the carbon nanotubes and in turn melt an embedded healing agent that will flow into and seal the crack. Credit: Rensselaer/ N. Koratkar. Usage Restrictions: Please include photo creditCaption: Professor Nikhil Koratkar has developed a new method to use carbon nanotubes for both detecting and repairing tiny cracks in nearly any polymer structure. In this image, carbon nanotubes are randomly dispersed in an epoxy resin, which can be molded into different structures.
By infusing the polymer with electrically conductive carbon nanotubes and monitoring the electrical resistance at different points in the structure, he can pinpoint the location and length of even the tiniest stress-induced crack. Once a crack is located, Kotakar can then send a short electrical charge to the area in order to heat up the carbon nanotubes and in turn melt an embedded healing agent that will flow into and seal the crack. Credit: Rensselaer/ N. Koratkar. Usage Restrictions: Please include photo credit.

New technology enables real-time diagnostics and on-site repair

Troy, N.Y. – Adding even a small amount of carbon nanotubes can go a long way toward enhancing the strength, integrity, and safety of plastic materials widely used in engineering applications, according to a new study.

Researchers at Rensselaer Polytechnic Institute have developed a simple new technique for identifying and repairing small, potentially dangerous cracks in high-performance aircraft wings and many other structures made from polymer composites.

By infusing a polymer with electrically conductive carbon nanotubes, and then monitoring the structure’s electrical resistance, the researchers were able to pinpoint the location and length of a stress-induced crack in a composite structure. Once a crack is located, engineers can then send a short electrical charge to the area in order to heat up the carbon nanotubes and in turn melt an embedded healing agent that will flow into and seal the crack with a 70 percent recovery in strength.

Real-time detection and repair of fatigue-induced damage will greatly enhance the performance, reliability, and safety of structural components in a variety of engineering systems, according to principal investigator Nikhil A. Koratkar, an associate professor in Rensselaer’s Department of Mechanical, Aerospace and Nuclear Engineering

Details of the project are outlined in the paper “In situ health monitoring and repair in composites using carbon nanotube additives,” which was published online this week by Applied Physics Letters. Rensselaer graduate students Wei Zhang and Varun Sakalkar were co-authors of the paper. The team has been working on the project for more than 18 months.

The majority of failures in any engineered structure are generally due to fatigue-induced microcracks that spread to dangerous proportions and eventually jeopardize the structure’s integrity, Koratkar said. His research is looking to solve this problem with an elegant solution that allows for real-time diagnostics and no additional or expensive equipment.

Koratkar’s team made a structure from common epoxy, the kind used to make everything from the lightweight frames of fighter jet wings to countless devices and components used in manufacturing and industry, but added enough multi-walled carbon nanotubes to comprise 1 percent of the structure’s total weight. The team mechanically mixed the liquid epoxy to ensure the carbon nanotubes were properly dispersed throughout the structure as it dried in a mold. The researchers also introduced into the structure a series of wires in the form of a grid, which can be used to measure electrical resistance and also apply control voltages to the structure.

By sending a small amount of electricity through the carbon nanotubes, the research team was able to measure the electrical resistance between any two points on the wire grid. They then created a tiny crack in the structure, and measured the electrical resistance between the two nearest grid points. Because the electrical current now had to travel around the crack to get from one point to another, the electrical resistance – the difficulty electricity faces when moving from one place to the next – increased. The longer the crack grew, the higher the electrical resistance between the two points increased.

Koratkar is confident this method will be just as effective with much larger structures. Since the nanotubes are ubiquitous through the structure, this technique can be used to monitor any portion of the structure by performing simple resistance measurements without the need to mount external sensors or sophisticated electronics.

“The beauty of this method is that the carbon nanotubes are everywhere. The sensors are actually an integral part of the structure, which allows you to monitor any part of the structure,” Koratkar said. “We’ve shown that nanoscale science, if applied creatively, can really make a difference in large-scale engineering and structures.”

Koratkar said the new crack detection method should eventually be more cost effective and more convenient than ultrasonic sensors commonly used today. His sensor system can also be used in real time as a device or component is in use, whereas the sonic sensors are external units that require a great deal of time to scan the entire surface area of a stationary structure.

Plus, Koratkar’s system features a built-in repair kit.

When a crack is detected, Koratkar can increase the voltage going through the carbon nanotubes at a particular point in the grid. This extra voltage creates heat, which in turn melts a commercially available healing agent that was mixed into the epoxy. The melted healing agent flows into the crack and cools down, effectively curing the crack. Koratkar shows that these mended structures are about 70 percent as strong as the original, uncracked structure – strong enough to prevent a complete, or catastrophic, structural failure. This method is an effective way to combat both microcracks, as well as a less-common form of structural damage called delamination.

“What’s novel about this application is that we’re using carbon nanotubes not just to detect the crack, but also to heal the crack,” he said. “We use the nanotubes to create localized heat, which melts the healing agent, and that’s what cures the crack.”

Koratkar said he envisions the new system for detecting cracks to eventually be integrated into the built-in computer system of a fighter jet or large piece of equipment. The system will allow the operator to monitor a structure’s integrity in real time, and any microcracks or delamination will become obvious by provoking a change in electrical resistance at some point in the structure.

The system should help increase the lifetime, safety, and cost effectiveness of polymer structures, which are commonly used in place of metal when weight is a factor, Koratkar said. There is also evidence that carbon nanotubes play a passive role in suppressing the rate at which microcracks grow in polymeric structures, which is the subject of a paper Koratkar expects to publish in the near future.

The research is team is now working to optimize the system, scale it up to larger structures, and develop new information technology to better collect and analyze the electrical resistance data created from the embedded grid and embedded carbon nanotubes. ###

The ongoing research project is funded in part by the National Science Foundation and the U.S. Army.

About Rensselaer: Rensselaer Polytechnic Institute, founded in 1824, is the nation’s oldest technological university. The university offers bachelor’s, master’s, and doctoral degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences.

Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of fields, with particular emphasis in biotechnology, nanotechnology, information technology, and the media arts and technology. The Institute is well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.

Contact: Michael Mullaney mullam@rpi.edu, 518-276-6161. Rensselaer Polytechnic Institute

Technorati Tags: or and and or and or MRSA: Methicillin-resistant Staphylococcus aureus and Thomas Edison and Nanowire generates power by harvesting energy from the environment