Highlights

2006 Highlights [total: 69 :: View full text :: Titles only]

Brown University

Research Highlights Summary [Research]
Periodically, the MRSEC posts scientific nuggets, i.e. brief one or two page descriptions of important scientific or technological discoveries and innovative new outreach initiatives which have resulted from NSF or other support. Feel free to explore the ones that we have provided here. The nuggets are in .pdf format. Fatigue Reliability Test System Suraj P. Gorkhali, Jose Vedrine, Gregory P. Crawford Numerical simulations of propulsion mechanisms in the Listeria bacterium A.F. Bower Ductile Fracture in Steel C.L. Briant, A. Needleman, L. Chuzhoy, D.H. Sherman Electromechanics of Thin Nanotube Films Electromechanics of Thin Nanotube Films Jose Vedrine, Gregory P. Crawford Defect volumes in a conducting oxide determined from combined mechanical and electronic measurements David C. Paine, Greg Crawford, Eric Chason, Burag Yaglioglu Theory for Polymorphism of Bacterial Flagella Srikanth V. Srigiriraju and Thomas R. Powers A study of stress and microstructure evolution in TiO2 thin-films derived from solution methods Rankin

California Institute of Technology

The Eyes Have It [Research]
Researchers in the Center for the Science and Engineering of Materials (CSEM) at the California Institute of Technology are developing a new class of biomaterials for use in surgery and regenerative medicine. These new materials are produced by genetic engineering, and consist of pieces of natural proteins that have been stitched together in new ways to allow control of both their mechanical properties and their interactions with cells and tissues after surgical implantation. In collaboration with researchers at the University of California, San Francisco, and at Calhoun Vision, Inc., CSEM scientists are exploring the use of their materials in eye surgery. The figure shows a protein lens that has been surgically implanted into the cornea of a rabbit eye; the green dye allows researchers to monitor the rate at which the cornea heals over the lens to incorporate the implant into the corneal tissue. The figure on the left shows the exposed lens immediately after surgery; that on the right shows the fully healed cornea after seven days. Procedures such as this might one day allow surgical correction of corneal defects caused by injury or disease, and might replace eyeglasses, contact lenses, or LASIK surgery as means of correcting less-than-perfect vision.


Active Nanophotonic Materials and Devices [Research]
The recent decade has seen an explosion of optical communication. Yet much of the information processing is conducted electronically since there have been few truly tunable optical devices. Ferroelectric materials offer a potential solution. They possess interesting nonlinear properties that can be used to design and fabricate unique active tunable nanophotonic devices. Photonic crystals are synthetic hetero-structures that provide an unprecedented ability to manipulate light including slowing down and reflecting selected frequencies. These structures are typically fabricated using glass and their properties are fixed. The calculations conducted in our interdisciplinary research group on Ferroelectric Nanophotonic Materials show that we can make such devices tunable by fabricating them out of ferroelectric materials. The first figure on the left shows the first ever ferroelectric photonic crystal fabricated on a thin film. The nonlinear properties of ferroelectrics also provide tunability to other nanophotonic devices. The images on the right show the use of ferroelectric films on toroidal resonators. These were fabricated using CSEM facilities.

Carnegie Mellon University

X-ray Vision for Materials [Research]
R.M. Suter /CMU MRSEC, Carnegie Mellon University, NSF DMR- 0520425 Researchers in the CMU MRSEC, together with scientists at the advanced photon source, have developed a non-destructive method to visualize the arrangement and orientation of individual crystals within a solid material. High energy X-rays from a synchrotron light source penetrate the material and interact with the crystals in their path. The pattern of transmitted X-rays that emerges from the material is then analyzed by custom software to determine the internal structure of the material. Because the complete X-ray/crystal interaction is modeled, this technique yields far more data than is contained in conventional radiograms. This new tool allows scientists to see within opaque materials with unprecedented detail and, therefore, allows the visualization of a wide range of previously hidden processes, such as crack formation in structural materials The figure shows a two-dimensional slice of the microstructure inside of an aluminum wire, 1 mm in diameter (the blue circle). Each color corresponds to a different crystal orientation. This research was conducted by: R.M. Suter, C. Xiao, D. Hennessy, and U. Lienertb Carnegie Mellon, Department of Physics and Advanced Photon Source Read more: http://www.andrew.cmu.edu/user/suter/3dxdm/3dxdm.html Download .pdf file

Columbia University

Graphitic Carbon Produced at Very Low Temperatures [Education]
Graphitic Carbon Produced at Very Low Temperatures during the Synthesis of Iron Oxide NanoparticlesGraphitic carbon – structural forms of the element that are constructed exclusively from carbon atoms having trigonal planar coordination – is ordinarily produced under drastic physical and conditions, typically at temperatures in excess of 500 C. Columbia MRSEC scientists have uncovered a process by which this form of matter can assemble at temperatures as low as 110 C. During their development of a low-temperature synthesis of nanocrystals of iron oxides, Drs. Erich Walter, Louis Brus and Michael Steigerwald found that bis(cyclooctatetraene)iron, Fe(C8H8)2, an arcane organometallic compound, when exposed to dimethylsulfoxide, a chemically mild source of oxygen, yields not only the desired nanoparticulate Fe3O4 but also graphitic carbon. The carbon occurs as single sheets (graphene, Figure A), and in tubes (multi-walled carbon nanotubes, MWCNTs, Figure B).

Graphene and carbon nanotubes are remarkable materials that will be used in electronic- and energy-related science and engineering, but this applicability has been stymied until now by the scarcity of controllable methods of fabrication of specific types, sizes, and shapes of these apparently simple chemicals. Low-temperature chemical reactions such as this process under development at Columbia are particularly valuable because they are more controllable than the higher-temperature analogs. By using different chemical feedstock and appropriate auxiliary ligands, the Columbia MRSEC researchers believe they will be able to direct this catalytic process rationally to produce sheets or tubes of the desired sizes and shapes.
For more, see upcoming article in J. Am. Chem. Soc. or contact: Michael Steigerwald.

Cornell University

Is It A Solid or a Liquid? [Research]



Frozen Silicon “Trees” tell Story of Melting [Research]



Developing a “Lab-on-a-Particle” [Research]



Do not bend, fold or mutilate [Research]



Engineering Structural Colors Using Nonspherical Building Blocks [Research]



Better Electronics from Silicon Corrals [Research]



Partnering with a Charter School to Reach At-Risk Students [Education]



Inner City High School Students Investigate Time in Chemistry and Physics [Education]



Tight Nanostrings Have Better Tone [Research]



Using Templates to Conquer Disorder [Research]

Harvard University

Sub-Cellular Nanosurgery in Live Cells [Research]
A femtosecond laser is used to perform “nano” surgery on a living cell. The actin filaments in the cell have been fluorescently labeled using green fluorescent protein (GFP). When a single filament is cut, it retracts, much like a violin string that has broken. This demonstrates that the actin filaments in the cell are under tension, and hence are being “pulled” apart. As a result, the filaments retract when they are cut, as shown in the figure. This provides critical insight into the behavior of cytoskeletal network that plays a key role in determining the mechanical properties of the cell.

Johns Hopkins University

Asymmetrical Nanorings [Research]

The vortex state of a magnetic nanoring has special attributes of no magnetic poles nor stray fields. The circulatory magnetization can have two chiralities:, left-handed or right-handed, for storing "0" and "1", as shown in Fig. 1.
Fig. 1: Two chiralities of a magnetic nanorings for storing "1" and "0".
We have developed a new method for the fabrication of 100-nm magnetic nanorings using colloidal lithography. There are two switching processes of magnetic nanoring: the vortex process (V-Process), with the annihilation of the two poles (or domain walls), and the rotating onion process (O-Process), where the two poles move in unison in opposite direction. For the 100-nm symmetric nanoring, the fractions are 40% for V-Process and 60% for O-Process. For symmetric nanorings with a uniform crosssection, the two chiralities of magnetization cannot be controlled by magnetic field.
Very recently, using oblique angle etching we have obtained asymmetrical nanorings, in which the cross-section is continuously varying across the circumference In the asymmetrical nanorings, the domain walls preferentially moves towards the narrower sections of the asymmetrical nanorings as shown by our theoretical model. As a result, the fraction of the V-Process increases with theta, and reaching 100% at theta = 90 degrees.
Furthermore, we not only can achieve exclusively the vortex state, but also control the chirality of the vortex state being left-handed or right-handed by using the magnetic field applied along the asymmetric axis. These results indicate that nanorings provide a very favorable geometrical shape for the memory units such as those in MRAM. Magnetic nanorings can store information through its chirality but without generating stray field

Massachusetts Institute of Technology

A New High-Rate Environmentally Friendly Battery Material May Help Hybrid Electric Vehicles Get Up and Go [Research]
Widely used in laptop computers, digital cameras, and many other devices, lithium ion batteries store more energy for their weight, operate at a higher voltage, and hold a charge much longer than other rechargeable batteries. However, in some applications, such as hybrid electric vehicles, lithium ion batteries are limited by their poor ability to be quickly charged and discharged (as would be needed to capture the energy of a car when breaking). MRSEC researchers at MIT, in collaboration with scientists from the State University of New York at Stony Brook (SUNY), have modified the crystal structure of Li(Ni.5 Mn.5 )O2, a material that exhibits high energy density but loses almost of all its storage capacity when charged quickly. The new re-engineered crystalline form of this material exhibits more than a ten-fold increase in its capacity under high rate conditions.The directed reengineering of this material was only possible through a combination of first principles modeling to identify the rate-limiting aspects of the structure, and the utilization of sophisticated characterization tools such as NMR and neutron diffraction. Because this material does not contain cobalt, a relatively expensive element present in current battery materials, it has the potential to be a safer, non-toxic and inexpensive battery material for use in hybrid electric cars.
[ Download .pdf ] 356kb


Symposium Highlights New Research Developments [Industry]

In October 2005, a “Materials Day at MIT” outreach symposium was held that focused on new research developments from the MIT MRSEC program. This full day symposium, organized by MIT’s Materials Processing Center (MPC) and Industrial Liaison Program (ILP), was attended by representatives from a total of 42 different companies. Also in attendance were about 65 members of the MIT community, including faculty, graduate and undergraduate students. The program was entitled “Frontiers in Materials: Interdisciplinary Research in Materials Science and Engineering” and included presentations by the MRSEC director, leaders of the MRSEC interdisciplinary research groups (IRGs) and IRG investigators.At the end of the technical program, a poster session/competition and social was held that included 75 poster presentations from both MRSEC students and post-doctoral associates and group members from the wider MIT materials research community. The poster competition was judged by representatives from companies such as Analog Devices, Novartis, Lockhead-Martin, and Lucent Technologies. Five prizes were awarded to students in recognition of their excellent poster presentations, including three MRSEC supported students. The various participants had an opportunity to interact with a full complement of MRSEC faculty, students and postdoctoral associates during the technical program, at a sponsored lunch event and during the poster session.

Northwestern University

Northwestern University Collaboration with Art Insitute of Chicago [Education]
Art Institute of Chicago - Northwestern University Program in Conservation Science*
Professor Katherine Faber, Northwestern Liaison
Dr. Francesca Casadio, Mellon Conservation Scientist
This is the nation’s first multi-year collaboration in conservation science to involve an art museum and a university. The objectives are to offer a model for integrative and cross-disciplinary collaboration among museums, universities and scientific institutions in an effort to enhance the field of conservation science in the United States as well as to strengthen the Art Institute’s research capabilities.

During the past year, funded by an initial $50,000 grant from Mellon, Northwestern and the Art Institute demonstrated that interesting conservation problems involving some of the museum’s ancient jades and Chinese bronzes existed and could best be addressed collaboratively. The partners will now broaden their work as they continue to conduct important interdisciplinary research and offer education programs focused on fundamental issues involving science and art that require outstanding research quality and intellectual breadth.
The new funding will extend the existing conservation science program into three main components:
• Collaborative research projects focused on Asian art (mainly jades and ancient Chinese bronzes), modern art materials (for paintings and sculptures) and studies of artists’ materials and techniques (for scholarly purposes and to assist authentication and determine provenance).
• Exploratory research grants to develop innovative scientific techniques for looking at art.
• A seminar series to stimulate creative thinking through presentations and discussions among scientists, curators and conservators. (The seminars in 2006 will be held in the spring and summer.)
The Northwestern faculty currently involved in the program are Faber, who will continue her work determining the mineral composition of certain ancient Chinese jades; David Dunand, James N. and Margie M. Krebs Professor of Materials Science and Engineering, and Joseph Lambert, Clare Hamilton Hall Professor of Chemistry, whose work involves analyzing the composition and patinas of modern bronzes by artists such as Matisse, Brancusi and Picasso, and investigating the casting technology of bronzes from the early Western Zhou Dynasty using the powerful X-rays at Argonne’s Advanced Photon Source; and Kimberly Gray, associate professor of civil and environmental engineering, who, using tiny paint chips from Georges Seurat’s painting “A Sunday on La Grande Jatte,” is studying the aging process of the pigment zinc yellow.
* Funded by the Mellon Foundation


NWU Collaboration with Art Insitute of Chicago [Research]
Art Institute of Chicago - Northwestern University Program in Conservation Science*
Professor Katherine Faber, Northwestern Liaison
Dr. Francesca Casadio, Mellon Conservation Scientist
This is the nation’s first multi-year collaboration in conservation science to involve an art museum and a university. The objectives are to offer a model for integrative and cross-disciplinary collaboration among museums, universities and scientific institutions in an effort to enhance the field of conservation science in the United States as well as to strengthen the Art Institute’s research capabilities.
During the past year, funded by an initial $50,000 grant from Mellon, Northwestern and the Art Institute demonstrated that interesting conservation problems involving some of the museum’s ancient jades and Chinese bronzes existed and could best be addressed collaboratively. The partners will now broaden their work as they continue to conduct important interdisciplinary research and offer education programs focused on fundamental issues involving science and art that require outstanding research quality and intellectual breadth.
The new funding will extend the existing conservation science program into three main components:
• Collaborative research projects focused on Asian art (mainly jades and ancient Chinese bronzes), modern art materials (for paintings and sculptures) and studies of artists’ materials and techniques (for scholarly purposes and to assist authentication and determine provenance).
• Exploratory research grants to develop innovative scientific techniques for looking at art.
• A seminar series to stimulate creative thinking through presentations and discussions among scientists, curators and conservators. (The seminars in 2006 will be held in the spring and summer.)
The Northwestern faculty currently involved in the program are Faber, who will continue her work determining the mineral composition of certain ancient Chinese jades; David Dunand, James N. and Margie M. Krebs Professor of Materials Science and Engineering, and Joseph Lambert, Clare Hamilton Hall Professor of Chemistry, whose work involves analyzing the composition and patinas of modern bronzes by artists such as Matisse, Brancusi and Picasso, and investigating the casting technology of bronzes from the early Western Zhou Dynasty using the powerful X-rays at Argonne’s Advanced Photon Source; and Kimberly Gray, associate professor of civil and environmental engineering, who, using tiny paint chips from Georges Seurat’s painting “A Sunday on La Grande Jatte,” is studying the aging process of the pigment zinc yellow.
* Funded by the Mellon Foundation


Synergistic Linear and Nonlinear Phenomena in Multifunctional Oxide Ceramic Systems [Research]
Vinayak P. Dravid,
Northwestern University
IRG1, Synergistic Linear and Nonlinear Phenomena in Multifunctional Oxide Ceramic Systems
The reduced size of materials with controlled internal structure (i.e., grain size, crystal orientation, etc.) leads to novel, unexpected phenomena and a very broad spectrum of technologically significant properties. In view of this scientific appeal and technological implications, we have developed a versatile nanopatterning technique termed as soft-electron beam lithography (soft-eBL). This approach synergistically combines the advantages of conventional electron beam lithography and wet chemistry routes for patterning nanostructures of metal oxides and composites. The unique capabilities of soft-eBL include the ability to pattern 2D functional inorganic structures as small as 30nm. In addition, it is capable of site-specifically patterning multidimensional nanostructures in a facile manner on almost any substrate. It was further demonstrated that soft-eBL is capable of building 3D hierarchical multifunctional nanostructures, which can be extremely challenging for traditional ceramic patterning approaches.

Pennsylvania State University

Microdisplacement: Printing patterns with diverse inks [Research]

Penn State researchers have designed a new patterning strategy, microdisplacement printing, which can stamp complex chemical patterns onto a substrate without mixing between the different "inks." A self assembled monolayer is a single layer of highly ordered, closely packed molecules sitting atop a surface such as gold. A self-assembled monolayer of 1-adamantane-thiolate, which does not pack so tightly, is vulnerable to displacement by more tightly packing molecules. In microdisplacement printing, a molecular "ink stamp" is pressed into an adamantane-thiolate monolayer. Everywhere that the stamp touches, the chemical "ink" displaces the adamantanethiolate. Unlike the stamping of inks onto a normal surface, in microdisplacement printing the preexisting monolayer of adamantanethiolate blocks the spread of the ink.
Using microdisplacement printing, we have patterned not only molecules that are compatible with current microcontact techniques, but also molecules that are too mobile on a surface to be patterned by conventional methods, such as short-chain alkanethiols. This fine degree of control allows us to stamp many different inks in sequence to form complex multi-component patterns-like printing in many colors instead of just black and white. In the future, we may even be able to insert single molecules at specified locations. This work initiated the commercial synthesis of 1-adamantanethiol by Sigma-Aldrich; our continuing relationship with them focuses on making molecules of all sorts for patterning: a new stable of molecular inks.


Nanocar: Smooth Ride on Fullerene Wheels [Research]
In MRSEC-sponsored research, Kevin Kelly, Andrew Osgood, Yasuhiro Shirai, James Tour and Yuming Zhao at Rice university have produced a nanometer-scale car with fullerene wheels that rotate about axles and guide the motion of the nanocar across a substrate. The nanocar, synthesized in Tour's group, is composed of a single organic molecule with four C60 molecules as wheels, mounted on freely rotating axles and attached to a central chassis. The entire vehicle is only a bit wider than a strand of DNA.
In addition to the synthetic tour de force, a key advance in this research was demonstrating that the wheels actually roll, rather than slide. If the cars simply slid across the substrate, then they would skid equally well in all directions. By observing the nanocars with a scanning tunneling microscope, Kelly and Osgood demonstrated that the cars move back and forth perpendicular to their axles more easily than they move side to side. In other words, the fullerene wheels have traction and keep the cars on track. In a second test, an alternative tripod-shaped "vehicle," with three axles all pointing outwards from a central core, simply spins in place.
Future goals in nanovehicular research include installing a light-driven engine in the car, and designing a nanotruck that is capable of carrying payload.


Fiber Integration: Semiconductors encased in glass [Research]
Penn State researchers John Badding, Venkat Gopalan and Vincent Crespi, working in close collaboration with Pier Sazio at the University of Southhampton, have succeeded in a task that at first sight may seem impossible: depositing uniform, dense conformal semiconducting nanowires deep within the pores of microstructured optical fibers. The resulting silicon and germaniumnanowires are by far the longest nanowires ever produced: tens of centimeters long, yet with inner pores so small that they cannot be resolved by scanning electron microscopy.
Badding and collaborators have extended the technique to produce radial semiconducting and metal/semiconductor heterostructures, field-effect transistors, infrared waveguides, optical modulators, compound semiconductors, metals, and even single-crystal silicon, all integrated intimately into the optical fiber geometry. In-pore photochemistry initiated by light focussed through the side of the fiber enables controlled placement of gold seed particles in three dimensional arrays for fluid liquid-solid growth of crystalline silicon.
Ultrahigh pressure, which can be sustained due to the great mechanical strength of high-quality optical fibers, facilitates mass transport into these highly confined spaced and induces the exceptionally uniform conformal filling that is necessary to obtain nearly perfect filling of these extreme aspect ratio pores. By integrating the design flexibility of microstructured optical fibers with the compositional control of chemical vapor deposition, this research may define a new generation of device geometries.


Molecular Rulers: A Marriage of Molecules and Metal [Research]
Molecules come in well-defined lengths: Penn State MRSEC researchers have invented a technique called "Molecular Rulers," in which molecular layers of precisely defined widths coat preexisting structures and form templates for patterning new structures with ever-smaller dimensions. Advanced lift-off processing and new bilayer resists, developed in 2005, have dramatically improved the uniformity and sharpness of the nanometer-scale gaps between the parent and daughter structures. These gaps can be tailored with molecular scale precision.
The Penn State team has developed hybrid nanolithographic strategies that combine molecular rulers and conventional fabrication methods to produce metallic structures with precise proximal placement. The hybrid strategy is compatible with commercial nanolithographic technologies. The gaps so produced allow study of the electrical and optical properties of nanoscale materials and new device structures. Multiplexed test-pad structures enable many parallel, single-gap measurements, with nano-scale structural characterization of selected individual gaps, to optimize the molecular ruler process.
The next goals are to reduce the line-edge roughness of the metal electrodes and to fabricate thin-film transistors and nanowires. By implementing advanced hybrid strategies, molecular rulers become technologically compatible and economically attractive. As lithography presses toward ever-decreasing dimensions, bottom-up methodologies using novel parallel technologies such as molecular rulers can help to circumvent the crippling costs projected for conventional approaches.


Magnetic Frustration by Design: Spins Can’t Always Get What They Want [Research]
Frustration is not only a state of mind, but also a state of matter wherein the interactions among different subunits cannot all be satisfied. Ordinary water ice is highly frustrated: there are many many different ways in which the protons within the lattice of ice can be arranged, and all are equally good (or bad, depending on your point of view).
Because of this so-called macroscopic ground state degeneracy, water ice has finite entropy, even at absolute zero. The “spin ices” are a class of magnetic materials wherein the spins of electrons play the same role as the protons in water ice: they have a huge multiplicity of arrangements at absolute zero, all of which have the same energy and none of which is preferred over the others.
A research team in the Penn State MRSEC, in collaboration with Chris Leighton at the University of Minnesota, has produced a new form of frustrated matter, a two-dimensional lattice of magnetic islands. These islands act as tiny bar magnets arranged on a carefully designed lattice so that the north and south poles of the bars cannot all align so as to optimize their mutual interactions. Instead they are frustrated, and are trapped within a set of distinct but energetically equivalent configurations.
Not only does this work open a door to designable and resolvable frustrated systems, but with magnetic storage media evershrinking in size, these mechanisms of frustration may find application in designing media wherein the bits of information can be closer together without interfering. This project, begun as a MRSEC seed, is now funded by the Army Research Office.


Catalytic Pumping: Electrokinesis arrested [Research]
In 2004, a Penn State MRSEC team showed that bimetallic platinum/gold nanorods could swim at speeds up to 20 microns per second by catalyzing the decomposition of hydrogen peroxide. Nickel stripes added to the motors allowed them to be steered using weak magnetic fields as a "remote control". Microgears formed from platinum and gold rotated in hydrogen peroxide solutions.
In 2005, MRSEC researchers� have inverted the system: instead of moving catalytic structures through a static solution, a static silver/gold catalytic structure pumps the solution past it. The action of these micropumps is revealed by tracer particles in solution. These particles not only respond to the drag forces from the convecting fluid, but also respond electrophoretically to the electric fields created by the catalytic electrochemical cell: particles with different surface charges follow different paths in the fluid. If an insulating barrier is interposed between the silver disk and the gold substrate, then the fluid motion stops, thus providing definitive proof of an electrochemical mechanism. Current work on catalytic pumps and motors is expanding the capabilities of these autonomous microscale and nanoscale machines with lightinduced catalytic motion and new fuels such as hydrazine, a high energy density molecule used in rocket propulsion.
� This research team includes Walter Paxton, Tim Kline, Paul Lammert, Ayusman Sen, Tom Mallouk, Jeff Catchmark and Vincent Crespi.


Microtubules in Capped Channels: The Persistence of Circulation [Research]
In eukaryotic cells, kinesin motor proteins transport intracellular cargo along microtubules, 25 nm protein filaments that form the cell cytoskeleton. This biomotor transport system is of fundamental importance in cell function and dysfunction, and provides a model system for nano- and microscale transport in engineered systems. MRSEC researchers Huang, Uppalapati, Hancock, and Jackson are developing techniques to control the direction and concentration of microtubules driven by immobilized kinesin motors to develop an alternative to fluid pumping for microfluidics applications. Gaining control over these subcellular structures will also enable the development of improved experimental systems to study the organization of motors and microtubules that underlies complex cellular process such as cell division.
Recently, we developed a new approach for organizing and aggregating aligned microtubules within a ring structure. Microchannels 4-6 m wide and 1 m deep are etched in glass and bonded to a top coverglass to create an enclosed channel. Kinesin motors are immobilized in the channel, and a neighboring reservoir is filled with microtubules in solution. The kinesin biomotors carry the microtubules into the 70 m ring; tubules that travel counterclockwise continue around the circle, while those traveling in the opposite direction exit the ring after about half a revolution. Over half an hour, hundreds of isopolar microtubules collect in the ring, ready for later deployment as a unidirectional and wellcontrolled population. This array of co-aligned microtubules is analogous to structures found in cells, and is a significant leap in the control of these subcellular structures.

Princeton University

IRG 3: Patterning of Organic Materials for Organic Electronic Devices [Research]
A team of Princeton researchers has developed an enabling technique for manufacturing electro-optical devices from organic semiconductors. The method relies on a modeling framework to describe different material transfer modes that occur when the organic materials are "stamped" onto an already patterned substrate, which allowed the Princeton team to cleanly transfer an organic thin film from a stamp to a patterned substrate without leaving any voids.


IRG 2: Breaking the Mold to Produce Submicron Polymeric Gratings with Large Areas [Research]
Princeton scientists have developed a new method for making gratings by prying apart two rigid plates that sandwich a thin, glassy polymeric film. The process fractures the film into complementary sets of ridges on each plate, with highly uniform ridge spacings ranging from 200 nm to 200 µm, scaling directly with the film thickness.


Supercurrents Flex Cantilever to Reveal Vortices [Research]
A soft cantilever beam, which can detect a very weak force, has been used by IRG1 researchers to uncover a striking property of cuprate superconductors: that trace supercurrents surrounding magnetic flux vortices persist for tens of degrees above the superconducting transition temperature Tc. The field needed to unbind these paired electrons is 60-100 times stronger than that inside a clinical MRI machine.

Stanford/ IBM ARC/ UC Davis/ UC Berkeley

Label-Free Bioanalytical Detection Using Membrane-Coated Silica Nanoparticles [Research]
Michael M. Baksh, Esther M. Winter, Nathan G. Clack and Jay T. Groves: University of California, Berkeley and Lawrence Berkeley National Lab
• Membrane-coated silica particles exhibit colloidal phase transitions that are governed by membrane surface interactions.
• Collective phase behavior of the beads serves as a cooperative amplifier; a readily detectable response from small numbers of microscopic binding events between ligands and membrane-bound protein(s) of interest alters the structure of the colloidal dispersion in measurable ways.
• Further statistical analysis of bead pair distribution functions enables quantitative determination of binding affinities.
• This technology has already been patented, and is currently being licensed by NuvoMetrix Inc. for commercialization.
Silica microbeads are coated with synthetic or natural membranes containing ligand of interest. Beads are allowed to settle to the bottom of a well.
Beads spontaneously form two-dimensional structures.
Radial distribution function (to measure changes in colloidal structure) varies continuously with the concentration of ligand bound to the bead surface.
Baksh, Jaros, & Groves, Nature 427:p.139-141 (2004) Winter & Groves, Anal, Chem 78:p. 174-180 (2006)


The Key to Making High Mobility Polymer Thin Film Transistors: Nucleation of Crystals Off of the Gate Dielectric [Research]

When conjugated polymer crystals nucleate off of the gate dielectric, the conjugated backbones, shown in red, are all aligned. Charge can easily hop from one grain to another.
Proven strategies for nucleating crystals on the dielectric
* Make the dielectric smooth
* Coat the dielectric with OTS
* Use high boiling point solvent or anneal the film
* Use high molecular weight polymers.
Download .pdf


Simulations of Polyphenylacetylene (PPA) “Foldamers”. Vijay Pande, Stanford University. [Research]
1. What are PPA “foldamers”

1. nonbiological polymers that fold
2. model systems for self-assembling nano structures
3. challenge for simulation: long timescale and complex dynamics

2.  New results

1. longer chains considerably are more complex: multiple traps and remarkable complexity
2. new methods used to predicted long timescale behavior: Markovian model and Folding@Home grid computing
3. Folding@Home: a new paradigm of combined research and outreach
Work performed by Sidney Elmer, CPIMA supported graduate student
Download .pdf


Chemical Imaging of Lipid Domains by High-Resolution Secondary Ion Mass Spectrometry (HR-SIMS) [Research]

Marjorie Longo, UC Davis; Steve Boxer, Stanford University
Phase separated supported lipid bilayers were chemically imaged by HR-SIMS performed with the NanoSIMS 50 (Cameca Instruments). A focused Cs+ ion beam is rastered across the sample, extensively fragmenting the surface components. Secondary ions of up to 5 different masses are simultaneously detected and a lateral resolution of 50 nm can be achieved. In our experiments, a unique stable isotope was selectively incorporated into each membrane component, and the intensity and location of the isotopically enriched secondary ions were used to create a component-specific image of the phase separated lipid bilayer.



Patterning of Large Arrays of Organic Semiconductor Single Crystals [Research]
Field-effect transistors made of single organic crystals are ideal for studying the charge transport characteristics of organic semiconductor materials. Their outstanding device performance, relative to that of transistors made of organic thin films, makes them also attractive candidates for electronic applications such as active matrix displays and sensor arrays. The only approach currently available for creating single crystal devices is manual selection and placing of individual crystals—a process prohibitive for producing devices at high density and with reasonable throughput. We developed a method for effectively fabricating large arrays of single crystals of a wide range of organic semiconductor materials directly onto transistor source-drain electrodes. We fabricated large arrays of high-performance organic single-crystal field effect transistors with mobilities as high as 2.4 cm2/Vs and on/off ratios greater than 107, and devices on flexible substrates that retain their performance after significant bending. These results suggest that our fabrication approach constitutes a promising step that might ultimately allow us to utilize high-performance organic single crystal field-effect transistors for large-area electronics applications.


a, Schematic outline of the procedure: print with PDMS stamps with relief features that are inked with a thick OTS film and then press onto the substrates, place patterned substrate in vacuum-sealed tube in a temperature gradient furnace tube with the organic source material for growth of patterned single crystals. b, Patterned single crystal arrays of Pentacene c, Rubrene d, C60

SUNY at Stony Brook - Garcia Polymer Alumni Center

Toxicity of Citrate/Gold Nanoparticles on Human Dermal Fibroblasts [Research]
The nanoscale engineering is one of the most dynamic domains at the interface between electronics, physics, biology and medicine. As there is no regulation yet, concern about future health problems is raising. We have investigated the cytotoxicity of Citrate/Gold nanoparticles at different concentrations and times. Major effects on cells appeared as a result of the internalization of nanoparticles, such as disruption of the actin cytoskeleton, loss of spreading and growth, as well as protein synthesis, and reduction of phagocytosis of bacteria. These factors can have serious consequences and impair wound healing, immunological response, and nervous junctions.
Human phagocytes that were exposed to nanoparticles digest 40% fewer bacteria than the unexposed cells. This can compromise the immune response.

SUNY Stony Brook - Thermal Spray Alumni Center

Eu-doped Y2O3 phosphor films through a precursor plasma spraying technique [Research]
Europium-doped yttrium oxide (Eu-Y2O3) luminescent films have been produced directly from a solution precursor using a radio frequency (RF) plasma spray technique. Highly crystalline and luminescent films were grown on Si (100) and steel substrates by this process. X-ray diffraction analyses on these films confirm that polycrystalline cubic Y2O3 phase has formed in-situ with no impurity phases. The enhanced photo luminescence (PL) intensity observed from these films is in all probability due to the highly crystalline nature of the coating combined with spherical morphology of the grains and the sub micron grain size.Red emission from Eu-Y2O3 Film when excited with a Mineralight UV lamp.

University of Massachusetts Amherst

Interfacial Assembly of Nanoparticles [Research]
The fabrication of functional nanostructured materials requires practical approaches to self-assembly on multiple length scales. Here, the directed self-assembly of functionalized, luminescent nanoparticles at oil-water interface, followed by crosslinking of the associated ligands, affords robust membranes. These composite membranes, nanometers in thickness, are shown to be effective diffusion barriers that have potential applications in controlled encapsulation and release. Cadmium selenide (CdSe) nanoparticles were used, since the photoluminescence of the particles provides a convenient means to monitor the spatial organization of the nanoparticles. The retention of the CdSe photoluminescence demonstrates that the nanoparticles remain unchanged during the manipulation. The concepts shown are non-specific and can be adapted to any nanoparticle and solvent combinations. (Y. Lin, H. Skaff, T. Emrick, A. D. Dinsmore and T. P. Russell, "A Membrane of Cross-Linked Nanoparticles," J. Am. Chem. Soc. 125, 12690-12691 (2003)).

University of Alabama

Molecular Charge Storage Materials - IRG2 [Research]
Jia Sun, Brad Payne, Greg Szulczewski, and Silas Blackstock (February, 2006)

WHAT: Redox-gradient dendrimers (RGDs) such as 8CN-4AA/PD have been designed to make amorphous films which will hold on to charge within the molecules (rather than conduct the charge). The 2 x 2 μm2 scans shown map the surface electric potential of the 8CN-4AA/PD film after electrification by the a conducting AFM tip. The images show the creation of a positive charge domain whose diffusion may be tracked in real time.
SO WHAT: The monitoring of charge diffusion in real time of these "slow" charge transport materials allows us to investigate and optimize the electric charge-retention properties of the RGD media which combine the chemical redox stability and ease of charging of hole-transport materials with the temporal translational stability of charges on electrified high-dielectrics. Applications of the RGDs would be as new materials for nanoscale data storage, memory operations, and switching.


Center for Materials for Information Technology Game Museum [Education]
Center for Materials for Information Technology at University of Alabama have recently gone live with 5 computer games targeted at middle school students. The games are designed to teach them about the periodic table and one is designed to teach about rock classifications.

University of California at Santa Barbara

MRL Faculty Milestones and Recognitions [Research]
Several MRL Faculty members were honored this summer and early fall for achievements in and significant contributions to their respective fields. The Millennium Prize Foundation of Finland announced that Professor Shuji Nakamura, who is involved with MRL's IRG-2 project on Oxide Based Semiconductors, is the sole winner of the 2006 Millennium Technology Prize, accompanied by one million euros (about $1.3 million in U.S. dollars). The Millennium Technology Prize was founded by the Millennium Prize Foundation of Finland, and is bestowed every 2 years by the President of the Republic of Finland. It is described by the Foundation as "the world's largest technology prize."
The Arthur C. Cope Award recognizes each year outstanding achievement in the field of organic chemistry. MRL faculty member Professor Gui Bazan is the 2007 recipient of this generous and very prestigous recognition which includes a medallion, cash award and unrestricted grant-in-aid. Previous UCSB faculty members who have been recognized by the Arthur Cope Fund Grant are Tom Bruice, Fred Wudl and Bruce Lipshitz.
MRL faculty member Glenn Fredrickson has been awarded the 2007 Polymer Physics Prize by the American Physical Society. The award recognizes outstanding accomplishment and excellence of contributions in polymer physics research. Past recipients of the prestigous APS honor include MRL faculty members Ed Kramer and Fyl Pincus.

University of Chicago

Multi-Assays of Cellular Kinase Activities [Research]
Working collaboratively, research groups at the Chicago MRSEC have developed new label-free analytical systems that utilize ultra-small sample sizes of cellular lysate, yet allow these single samples to be assayed for multiple kinase activities. The systems involve the integration of solid-phase biochip peptide arrays, mass spectrometric detection, and microfluidic networks. [1] We expect this strategy to aid drug discovery, diagnostics, and other basic research which rely substantially on enzyme assays.
[1] Combining Microfluidic Networks and Peptide Arrays for Multi-Enzyme Assays, J. Su, M. R. Bringer, R. Ismagilov, and M. Mrksich, J. Am. Chem. Soc., 127, 7289-7281, 2005.


Physics Today for a Brighter Tomorrow [Research]
In March, a group of physicists from the Chicago MRSEC visited Washington DC to talk about science to Congressional Representatives, their staff, and others. The message: basic research is vital to America's economy and our childrens' futures. In the photo, current MRSEC Director, Sidney Nagel (left) demonstrates the properties of materials to CUNY Prof. Myriam Sarachik (former President of the APS) and U.S. Rep. Vernon J. Ehlers(R-MI) as Leo Kadanoff (right), former MRSEC Director and currently President-Elect of the APS, looks on. This effort was sponsored by the Condensed-Matter Divison of the APS. Our MRSEC scientists are aware that research is only half of a scientist's job--the other half is telling people about it.


Granular Jets [Research]
When a marble or ball-bearing is dropped onto a bed of fine, loose sand, one first observes a broad splash of sand at impact. Then, a tall jet of granular material shoots up vertically. Experiments at the Chicago MRSEC in collaboration with researchers from the APS at Argonne have tracked the birth and evolution of these granular jets using the fastest x-ray based imaging performed to date (6000 video frames per second)[1]. The images show granular jets emerging from a bed of fine glass spheres after impact by a heavy steel sphere dropped from above. Results for four different ambient air pressures are given. Note the two-stage jet shape visible at intermediate pressures.
These jets are among the most spectacular manifestations of liquid-like behavior in granular materials. Although resembling similar phenomena in ordinary liquids, these jets form in the absence of any cohesive forces or surface tension yet their overall shape depends on the ambient pressure. The measurements at Argonne provide a new understanding of how granular jets are formed and establish how ambient gas pressure affects them.
[1] Formation of granular jets observed by high-speed X-ray radiography, J.R. Royer, E.I. Corwin, A. Flior, M.L. Cordero, M.L. Rivers, P.J. Eng, and H.M. Jaeger, Nature Physics, 1, 3, 164-167 (2005).


Fast Drying Produces Order [Research]
A collaboration of experimentalists and theorists at the Chicago MRSEC has discovered a new, general route for creating nanoparticle monolayers that retain order across millions of particles, without holes, while staying compact over macroscopic distances[1].
This new method exploits the observation that fast initial drying drives the nanoparticles into an interface between the suspending solvent and the surrounding air, where they form a two dimensional, single-particle-thin skin. This skin drapes itself over the substrate during the final drying stage, accommodating roughness, curvature, and even holes without losing integrity.
[1] Kinetically-Driven Self-Assembly of Highly-Ordered Nanocrystal Monolayers, Terry P. Bigioni, Xiao-Min Lin, Toan T. Nguyen, Eric Corwin, Thomas A. Witten, and Heinrich M. Jaeger, Nature Materials 5, 265-270 (2006).

University of Colorado

Halon Liquid Crystals [Research]
Center researchers have found liquid crystal phases in systems of circular or spherical particles, a surprise since liquid crystals usually appear in molecules shaped like sticks or plates. The trick is to give hard particles (purple) a soft repulsive "halo" (green) The resulting phase behavior is extraordinarily rich, including "lyotropic" liquid crystal phases and a variety of complex modulated crystal phases. These findings dramatically expand the range of possible modes of colloidal self-assembly, and suggest applications in the development of novel photonic crystals and functional nanostructures.

University of Maryland

Capturing Atomic Spirals [Research]
M. Ranganathan, D.B. Dougherty, W.G. Cullen, T. Zhao, J.D. Weeks and E.D. Williams Physical Review Letters 95, 225505 (2005) Defect structures serve as nucleation sources that allow growth and evolution of structure at temperatures far lower than perfect crystalline structure would allow. Screw dislocations, which form spiral growth/etch patterns when they evolve freely on a thin film surface, are the classical example of this behavior. Nanoscalecrystalline structures provide a mechanism for capturing the spiraling dislocation within the boundaries of thenanostructure. Such a trapped trapped structure no longer can spiral freely, and instead develops a periodic structure with a highly non-uniform angular frequency. Very simple physical phenomena -the free energy of a curved interface, and the Brownian motion of atoms at the dislocation edge, suffice to model the behavior quantitatively.
 
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University of Minnesota

Children learn about nanotechnology (MNDaily) [Education]

A team of a dozen third- and fourth-grade students forcefully stepped on the clear, white, sticky floor mat to remove the dust from their shoes before eagerly suiting up in full-body cleanroom suits at the University's Nanofabrication Center in the Electrical Engineering and Computer Science building Friday.
Dressed in the white "bunny suits" used to keep dust and dirt particles out of the nanofabrication labs, the two teams - named the Nano Monkey Legends and the Robo Monkey Bandits - called out "nano" and smiled while posing for a group photo. The monkey-themed team names stem from school tradition.
Delaney Perkins, a third-grader at Eisenhower Elementary School in Hopkins, where the 12 students attend, said the bunny suits are worn "so that dead hair and skin don't get into the nanotechnology stuff."
The tour gave Minnesota students participating in the 2006 FIRST LEGO League "Nanoquest" competition an opportunity to see nanotech labs and learn from experts and researchers in the University's Materials Research Science and Engineering Center.

University of Nebraska

Ballistic Anisotropic Magnetoresistance [Research]
Anisotropic magnetoresistance (AMR) is the difference in the resistivity of ferromagnetic materials in external magnetic field when the field is applied along or perpendicular to the current. In macroscopic materials the conductance is diffusive (the mean free path of the electron is much smaller than the device dimensions) and AMR is due to spin dependent scattering of impurities. Until recently AMR used to be the primary way of detecting magnetic fields (as in hard-drive read heads). By using first-principles electronic structure techniques and symmetry arguments a new ballistic AMR effect was predicted in atomic size wires (BAMR). The physics of BAMR is completely different because the electron traverses the wire without scattering. Thus, BAMR is an essentially quantum effect. In addition, BAMR can be an order of magnitude larger than AMR, of either sign, and has a characteristic stepwise dependence of the direction of the magnetic field. In-situ measurements of the angular dependence of the conductance in magnetically saturated Ni point contacts show the signature of this new phenomenon. Understanding electron conductance on the quantum level is essential for future electronics as the individual elements approach the atomic size dimensions. [Phys. Rev. Lett. 94, 127203 (2005)]
See below a schematic view of the atomic contact. The profile of the contact conductance as a function of the magnetic field direction.



Anisotropic Magnetism in Dilute Magnetic Semiconductors [Research]
Magnetocrystalline anisotropy is found in many magnetic materials which means that the energy of a magnet depends on the magnetization direction. This keeps our windshield wipers moving and our toy magnets attached to the fridge. However, on changing the direction of the field that aligns the magnetic moments, the aligned magnetization normally remains nearly unchanged. A strikingly different behavior has been found by researchers at the University of Nebraska MRSEC. The aligned moment of V-doped SnO₂ thin films changes by a factor of order two, and the symmetry axis of the moment anisotropy is unrelated to the symmetry axes of crystal and film. Figure 1 illustrates that the V atoms prefer to occupy sites in strongly distorted interstitial octahedra whose symmetry axes are unrelated to the film normal and to the a, b, and c axes of the SnO₂rutile structure. The interaction between the anisotropic moments involves the hopping of electrons which, in the presence of a strong electron spin-lattice interaction, amounts to the hopping of current loops (Fig. 2), which goes beyond the normal mechanism leading to ferromagnetism. The moment anisotropy is of orbital origin and expected to exhibit a particularly strong anisotropic electron scattering, which is of interest in spin electronics, and a new technology involving both magnetism and electronics.

 
 
 
 
 
 
 
 
 
Fig. 1. V atom (green) in the SnO₂ rutile structure. The gray area shows the location of the film plane.

 
 
 
 
 
 
Fig. 2. The arrows represent current densities due to interatomic hopping of current loops for (a) parallel and (b) antiparallel moments.


Controlling Magnetism through a Ferroelectric Switch [Research]
Multiferroic materials are of great scientific and technological interest due to their magnetoelectric properties, originating from the coupling between ferroelectric and ferromagnetic order parameters. The interplay between ferroelectricity and magnetism may allow a magnetic control of ferroelectric properties and an electric control of magnetic properties, and could yield conceptually new devices such as transducers converting between magnetic and electric fields and electrically-controlled magnetic data storage. Recently, it became possible to fabricate composite multiferroics by artificially making ferroelectrics and ferromagnets in nanoscale heterostructures. It was demonstrated that the magnetoelectric effect can be significant due to strong elastic interactions between the two ferroic constituents.
Researchers of the MRSEC at the University of Nebraska offer a different route to control the magnetism by electric fields. In the recent article published in Physical Review Letters [Duan et al., PRL 97, 047201 (2006)], they predict that it is possible to change the magnetization at the interface between ferromagnetic and ferroelectric materials by reversing the electric polarization of the ferroelectric. The origin of this phenomenon is the change in the bonding strength at the ferroelectric/ferromagnet interface due ferroelectric displacements altering the interface magnetization when the electric polarization reverses. Using a Fe/BaTiO₃ interface as a representative model the researchers show a sizable difference in magnetic moments of Fe and Ti atoms for the two opposite orientations of the electric polarization of BaTiO₃. The predicted magnetoelectric effect is much stronger than that in bulk single-phase multiferroics and comparable in magnitude with that observed in elastically-coupled composites. The experimental verification of this prediction will open a new venue for exploration in the search for improved magnetic data storage devices, sensors and transducers using electric field as the controlling mechanism.

Calculated charge density showing the change in the induced magnetic moment on the interface Ti atom with reversal of the electric polarization of BaTiO₃ layer (shown by arrow).


Light Used as a Magnetic Hammer [Research]
Scientists in the University of Nebraska MRSEC are using very short light pulses from a femtosecond laser to perturb magnetic materials and to probe their behavior at times after the perturbation. The light pulses are only about 100 millionth-billionths of a second long.
When the “pump” pulse strikes the sample, it acts like a magnetic hammer to quickly change the direction that the magnetization M points. M then spins around (precesses) very rapidly. The much weaker “probe” pulse comes along a short time later and measures the direction in which M points.
By adjusting the delay time between the pump and probe pulses, we get a detailed picture of how the magnetization precesses with time. These investigations provide information that is useful in such applications as magnetic information storage on hard disk drives.

N. I. Polushkin, S. A. Michalski, L. Yue, R. D. Kirby, Phys. Rev. Lett. 97, 256401 (2006).

University of Oklahoma / University of Arkansas

Forensic Science As A Springboard - OU RET’s Take Modules on the Road to Metrotech High School [Education]

“CSI is a hot topic, and that makes it fascinating to kids. But it’s also applied science, and it’s a powerful way to get kids involved in the scientific process: carefully documenting observations and analyzing results.” Merle Hunsaker, RET and science teacher.

During the summers of 2005-2007, C-SPIN is helping support the development of “CSI In The Classroom”, a comprehensive set of high school resources in fingerprint analysis, serology, microscopy, trace analysis, collisions, and document examination. Our modules went on their first road show in June, 2006 – a summer camp for under-

represented minorities at Metrotech High School in Oklahoma City. The results? Our RET’s report that student engagement was 100% and students remained focused on task for surprisingly long periods of time. The participants told us in post-evaluation that they never realized documentation and data analysis could be fun

[Education & Outreach]