David S. Ginley National Renewable Energy Laboratory
Michael J. Fasolka National Institute of Standards and Technology
Alfred Ludwig caesar, Bonn; Ruhr-Universitaet Bochum
Mikk Lippmaa Institute for Solid State Physics
Dutch Polymer Institute
National Institute of Standards and Technology
A1: Combinatorial Development of Energy Related Materials
Tuesday PM, November 27, 2007
Independence E (Sheraton)
2:30 PM - **A1.1
High-throughput Search for Energy Storage Materials and Hydrogen Catalysts by Means of Hydrogenography.
Ronald Griessen 1 , Robin Gremaud 1 , Herman Schreuders 1 , Chase Broedersz 1 , Bernard Dam 1 Show Abstract
1 Physics, VU-Amsterdam, Amsterdam Netherlands
Hydrogenography is a novel technique based on the optical changes induced by hydrogen ab- and desorption in metal films. Hydrogenography on thin films with a compositional gradient has the great advantage that it allows to measure simultaneously a huge number of samples (up to thousands) of different elemental compositions on only one wafer (each pixel of the recording camera corresponds essentially to one alloy composition). This enormously facilitates the search for new metal-hydrides with specific physical properties [1-3]. The compositional gradient thin films necessary for Hydrogenography are synthesised by co-sputtering on a 3 in wafer from three (up to six) off-centred magnetron sources. The hydride formation during ex-situ hydrogen exposition at well-defined temperatures and hydrogen gas pressures is monitored through the transparency of the films. Since all complex hydrides found so far have an electronic band gap their transparency is a good indicator of the amount of absorbed hydrogen. Hydrogenography is thus applicable to a large class of potential light-weight hydrogen storage materials.As an illustration of our technique I describe how Hydrogenography is used to optimize Magnesium-based metal hydrides. Some of these hydrides have gravimetric hydrogen capacities approx. 4 times higher than that of conventional NiMH batteries . From the simultaneous measurements of the enthalpy and entropy of formation of thousands of Mg-Ti-Ni hydrides we are able i) to determine the compositions with the best capacity and ab/desorption kinetics (the hydrogen sorption kinetics is directly amenable to the experiment as hydrogenographic data are continuously recorded during hydrogen ab/desorption) and ii) and to put in evidence remarkable correlations between enthalpy and entropy, a subject that has remained highly controversial for decades. Hydrogenography is also of great help in the search and optimisation of catalytic layers for hydrogen ab-and desorption . B. Dam et al.: Combinatorial thin film methods for the search of new lightweight metal hydrides, Scripta Materialia 56 (2007) 853-858 R. Gremaud et al.: Structural and optical properties of MgxAl1-xHy gradient thin films: a combinatorial approach, Applied Physics A: Mat. Science & Processing 84 (2006) 77 A. Borgschulte et al: High–throughput concept for tailoring switchable mirrors, Appl. Surf. Science 253 (2006) 1417–1423 D. M. Borsa et al: Structural, optical and electrical properties of Mg-Ti-H thin films, Phys. Rev. B (2007) in press A. Borgschulte et al.: Catalytic activity of noble metals promoting hydrogen uptake, J. of Catalysis 229 (2006) 263
3:00 PM - **A1.2
High Throughput Discovery of Materials for Hydrogen Storage.
Andrew Cooper 2 1 , Bien Tan 1 , Neil Campbell 2 , Abbie Trewin 1 2 , Ev Stoeckel 1 , Darren Bradshaw 1 , Matthew Rosseinsky 1 , Yaroslav Khimyak 1 , Hongjun Niu 1 , Chris Bray 1 , Fabing Su 1 , Haifei Zhang 1 , Colin Wood 1 Show Abstract
2 Centre for Materials Discovery, University of Liverpool, Liverpool United Kingdom, 1 Department of Chemistry, University of Liverpool, Liverpool United Kingdom
In this presentation we will describe the use of combinatorial approaches for the discovery of new materials for hydrogen storage. Practicable H2 storage is a very challenging goal, not least because it is highly multivariate in nature - a successful technology must hit a range of diverse and often orthogonal targets such as gravimetric capacity, volumetric capacity, cyclability, storage/release kinetics, lifetime, and cost. As such, the application of combinatorial methods to the search for new H2 storage materials may be a very powerful strategy. There are, however, a number of key measurements which are inherently difficult to carry out in a combinatorial or accelerated manner. For example, the parallelization of gas sorption measurements is challenging, particularly at elevated pressures. In this talk we will discuss the development of high throughput (HT) approaches in three key areas:(i) The automated synthesis and purification of libraries of microporous sorbents for gas storage applications using robotic synthesis platforms. We will show how we have used this methodology to discover, for example, microporous polymers with apparent BET surface areas of around 2000 m2/g and gravimetric H2 uptakes of around 4 wt.% at 77.3 K and 20 bar.(ii) The development of new HT characterization methods (gas sorption, FTIR, X-ray diffraction) for libraries of porous sorbents. We will show how appropriate instrumentation can greatly accelerate traditionallly slow and sequential measurement techniques.(iii) Combined methodologies for the HT discovery of new gas clathrate compositions with enhanced storage capacities and formation kinetics.Our strategy in each case can be described as "high-throughput, hypothesis-led" research (HT-HLR), as opposed to HT "screening". Throughout the talk we will outline the capabilities of the new Centre for Materials Discovery in Liverpool (www.materialsdiscovery.com), a bespoke facility opened in January 2007 which is dedicated to the accelerated discovery of new functional materials.
3:30 PM - A1.3
Establishment of Reaction Phase Diagrams of Pseudo Four-Components Li-Ni-Co-Ti Oxides Library.
Kenjiro Fujimoto 1 Show Abstract
1 Department of Pure and Applied Chemistry, Tokyo University of Science, Noda Japan
The cathode material for secondary lithium-ion batteries is usually made from the layered-type structure LiCoO2. However, the cobalt element in LiCoO2 has some problems about toxicity and high cost. Therefore, the exploration of candidate materials for the cathode material is heading to multi-element compounds such as LiNi0.8Co0.2O2 and Li[Ni1/3Co1/3Mn1/3]O2, since the electrochemical and safety characteristics are comparable or superior to LiCoO2. In this study, pseudo four-components Li-Ni-Co-Ti oxides were prepared and established reaction phase diagrams for finding newly functional materials by combinatorial high-throughput screening. Library was prepared by the “M-ist Combi” system based on electrostatic spray deposition method .Starting materials for preparation of pseudo four-components Li-Ni-Co-Ti oxides library used were LiNO3, Ni(NO3)2.6H2O, Co(NO3)2.6H2O and TiO2 nano-slurry. Each material was dissolved by the mixture of ethanol and butyl carbitol. And, the mixed solution is fed to stainless steel nozzle. Then, the solution is atomized from the top of stainless nozzle which applied at 3500V and deposited on the grounded and heated substrate at 673K. The deposited library was heat-treated in atmospheric air.The heat-treated library was evaluated by combinatorial powder X-ray diffractometer. The chemical component of after heat-treated library was analyzed by ICP emission spectroscopy method. Figures of reaction phase diagram based on results of x-ray diffraction measurements and chemical composition analysis were plotted using the XRDSuite program .From three-dimensional pseudo four-components reaction phase diagrams, new composition regions of single phase structure were found in a short time. In particular, the layered-type compounds were found wider composition region than the previous reported composition region of LiNi0.8-yCo0.2TiyO2 (0≤y≤0.1) . References K. Fujimoto, H. Takahashi, S. Ito, S. Inoue and M. Watanabe, Applied Surface Science 252 (2006), 2446-2449. I. Takeuchi, C.J. Long, O.O. Famodu, M. Murakami, J. Hattrick-Simpers, G. W. Rubloff, M. Stukowski and K. Rajan, Review of Scientific Instruments 76 (2005), 062223. H. Liu, J. Li, Z. Zhang, Z. Gong and Y. Yang, Electrochimica Acta 49(7) (2004), 1151-1159.
4:15 PM - **A1.4
High-Throughput Screening System for Thermoelectric Material Exploration Based on Composition-Spread Approach.
Makoto Otani 1 , Nathan Lowhorn 1 , Evan Thomas 1 , Winnie Wong-Ng 1 , Peter Schenck 1 , Martin Green 1 Show Abstract
1 Ceramics Division, NIST, Gaithersburg, Maryland, United States
4:45 PM - A1.5
Combinatorial Approach for Thermoelectric Materials through Bulk Composition-Spreads and Diffusion Multiples.
Atsushi Yamamoto 1 , Teruo Noguchi 1 , Yasuko Kato 1 , Haruhiko Obara 1 , Kazuo Ueno 1 , Satoaki Ikeuchi 2 , Tooru Sugawara 2 , Kenji Shimada 2 , Youichi Takasaki 2 , Yoshikazu Ishii 2 Show Abstract
1 Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki Japan, 2 , Ulvac-Riko, Inc., Kanagawa Japan
The chemical compositions of thermoelectric materials under exploration are getting more and more complex after stimulating findings of filled skutterudites, complex layered cobaltites, and complex half heusler alloys in the last decade. Most of the good thermoelectric materials are consisted of more than three elements. The experimental methodology for fast screening of thermoelectric material is strongly desired in R&D in this field. In this paper we describe a new attempt of high-throughput screening of thermoelectric materials combining the use of bulk composition-spread and the scanning thermal probe micro-analyzer (STPM). The STPM which was developed at AIST is capable of evaluating the lateral distribution of Seebeck coefficient and thermal conductivity simultaneously at scanning speed of 10000 points / 8 hours. For testing materials, bulk composition-spread of Bi-Sb-Te and Ni-Cu systems were used. These material systems were prepared by conventional powder metallurgy processes such as ball milling and hot-pressing. The composition-spread samples were also used for preparing diffusion multiples in order to examine more complex compositions. We will discuss the efficiency of this approach based on the experimental results of pseudo-binary Bi2Te3-Sb2Te3 and binary Ni-Cu system and their diffusion multiples. We will also discuss the applicability of this approach to other intermetallic compounds, mixed crystals and metallic alloys.
5:00 PM - A1.6
Combinatorial Searching for Noble Metal-based Amorphous Alloy Thin Films for Glass Lens Mold.
Junpei Sakurai 1 , Seiichi Hata 2 , Ryusuke Yamauchi 1 , Hiroyuki Tachikawa 1 , Akira Shimokohbe 1 Show Abstract
1 P&I Lab., Tokyo Insutitute of Technology, Yokohama Japan, 2 rontier Collaborative Research Center, Tokyo Insutitute of Technology, Yokohama, Kanagawa, Japan
5:15 PM - A1.7
Opto-Mechanical High-Throughput Characterization of Hydrogenation/Dehydrogenation Properties of Thin Metal Films.
Jialin Cao 1 , Alan Savan 1 , Alfred Ludwig 1 2 Show Abstract
1 Combinatorial Materials Science Group, caesar, Bonn Germany, 2 Institute for Materials, Ruhr-University Bochum, Bochum Germany
The development of new hydrogen storage alloys is essential for the future hydrogen economy. For an efficient development of new materials the preparation of thin films is advantageous as the composition and micro/nanostructure of thin films can be precisely tailored. Therefore, thin film composition spreads of binary and ternary Mg-based materials (selected from Mg-Ni-Ti-Al-B) were deposited by co-sputtering on micromachined Si cantilever arrays. A 10 nm Pd top layer was always used as an oxidation barrier and as a catalyst for hydrogen dissociation. The composition spreads were hydrogenated and dehydrogenated in a special pressure vessel, which allows the optical measurement of the hydrogen-induced deflection (stress-change) of up to 28 cantilevers (i.e. materials) in parallel as a function of hydrogen pressure (up to 50 bar) and/or temperature (up to 450°C). The measurement of hydrogen-induced stress is particularly attractive for screening experiments as this effect occurs in all materials which take up hydrogen. It was found that hydrogen-induced stresses can be correlated with the composition and microstructure of the thin films. Furthermore, the results of the opto-mechancial measurements are compared with alternative hydrogen screening experiments (purely optical, electro-chemical).
5:30 PM - A1.8
Discrete Combinatorial Ceramic Libraries Production through London University Search Instrument (LUSI).
Lifeng Chen 1 , Yong Zhang 1 , Julian Evans 1 , Shoufeng Yang 1 Show Abstract
1 School of Engineering and Materials Science, Queen Mary, University of London, London United Kingdom
5:45 PM - A1.9
High-Throughput Synthesis and Characterization of Bulk Ceramics from Dry Ceramic Powders.
Tobias Stegk 1 , Rolf Janssen 1 , Gerold Schneider 1 Show Abstract
1 Institute of Advanced Ceramics, Hamburg University of Technology, Hamburg Germany
A high-throughput experimental (HTE) setup was used to synthesize and characterize ceramic bulk samples in the lower yttria-regime of the binary material system zirconia-yttria. Libraries had a resolution of 0.5 mol-% yttria and were prepared using varying marginal systems as well as a number of liquid mixing aids. Automated powder X-ray diffraction (XRD) was applied to detect the monoclinic phase content retained after the heat-treatment on various positions for each sample. The phase information was compared to a benchmark library comprising conventionally prepared samples by means of a regression analysis and a mean deviation of monoclinic phase percentage. Out of the eight HTE-libraries, three showed a significant comparability to the benchmark library.
David S. Ginley National Renewable Energy Laboratory
Michael J. Fasolka National Institute of Standards and Technology
Alfred Ludwig caesar, Bonn; Ruhr-Universitaet Bochum
Mikk Lippmaa Institute for Solid State Physics
A2: High Throughput Measurements and Infomatics
Wednesday AM, November 28, 2007
Independence E (Sheraton)
9:00 AM - **A2.1
Landscape of Combinatorial Materials Exploration and Materials Informatics.
Chikyow Toyohiro 1 , T. Nagata 1 , N. Umezawa 1 , M. Yoshitake 1 , K. Ohmori 3 , T. Yamada 3 , M. Lippma 4 , H. Koinuma 1 2 Show Abstract
1 , NIMS, Tsukuba, Ibaraki, Japan, 3 Nanotechnology Research Laboratory, Waseda University, Shinjuku-ku Japan, 4 , University of Tokyo, Chiba, Kashiwa-shi, Japan, 2 , Japan Science and Technology Agency, Tokyo, Chiyodda-ku, Japan
It has passed more than 10 years since the modern combinatorial materials science appeared with new tools for high throughput characterizations. Recently this combinatorial methodology is recognized to be an innovative tool to discover new materials and expectation for this method is potentially increasing. At the same time, some similarity was found in different research field from the view point of materials. For example, in the modern large scale integrated circuit (LSI), due to the scaling down of the transistors, gate oxide material has been the most serious problem. At this moment, HfO2 based oxides are expected to be the candidate but materials exploration for the next generation has already started. Also the work function tuning for gate materials are required to make nano CMOS in future. Fermi level pinning at the interface between metal gate and gate oxides must be an urgently discussed. In the oxide thermoelectric materials, defect control and electron entropy are recognized to be key factors in better performance and these discussion are strongly related to the understanding of the leakage current mechanism in gate oxides. In the catalysis search based on metal alloys, some similarity with metal gate was found because they handles the almost same metals for catalysis and metal gate, where the surface potential, such as work function may links the two research field. Quite recently, metal/oxide couple, Pt/CeO2 can be replaced with PrRu catalysis. Here the metal/oxide interface seems to play a critical role in the performance. These facts remind us the combinatorial methodology is not only the tool for materials discovery but also glue to link different research field with a universal aspect. To make a clear vision of this combinatorial research landscape, materials informatics which gives us a visual image of the characters is inevitable. In this talk, we show some examples which combinatorial materials research makes the links and emphasize the importance of the materials informatics.
9:30 AM - **A2.2
Recent Advances in High Speed Particle Analysis using an Automated Scanning Electron Microscope.
Nicholas Ritchie 1 Show Abstract
1 Surface and Microanalysis Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
The traditional approach to particle analysis using a scanning electron microscope with energy dispersive x-ray detector has been to identify a small number (<~10 particles) which are judged to be representative by an experienced operator. These particles are analyzed for morphology and composition to the best of the operators ability and limited by the challenging nature of compositional analysis on particles. For some problems, this mode of analysis has proven satisfactory. Schemes have been developed to quantify x-ray spectra collected on particles, however under even the best of conditions, these schemes do not come close to the level of accuracy available from bulk, polished samples. In addition, this style of analysis is plagued with issues of operator and sampling bias.An alternative is to spend similar amounts of instrument time analyzing thousands of particles. Instead of exhaustively analyzing a few particles, thousands of particles are analyzed quickly (typically seconds per particle) – albeit with less precision and less accuracy on a particle-by-particle basis. Instead of allowing an experienced operator to decide based on a cursory review the underlying character of the sample, statistical metrics extracted from the particle data set are allowed to provide a description of the samples character.This technique relies on the advent of highly automated scanning electron microscopes optimized for particle analysis. The current state-of-the-art systems can size ~10 particles per second and collect an adequate EDS spectrum in a few seconds (or less using a newer silicon drift x-ray detector.) The first instruments of this type were developed during the 1980's and have undergone refinement since. Since the instrumentation is entirely under computer control, it is possible to define analysis conditions reproducibly and to a very large extent eliminate operator bias. The instrument can be left unattended for hours or days and large data sets consisting of particle images and spectra along with measurement summary tables readily collected. This technique is commonly applied to environmental, industrial, material science, pharmaceutical and other particle data sets.More recently the abundance of high speed, high capacity computers have permitted more sophisticated analysis of the resulting data sets. This starts with our ability to quantify the spectral data and extends to our ability to data mine and cluster the resulting data set. As a result, the nature of particle analysis on the scanning electron microscope has changed. We can now answer questions about relative populations of types of compositionally similar particles. Samples can be compared based on population statistics and not just the compositional analysis of a handful of “representative” particles.
10:00 AM - A2.3
Combinatorial Screening Using X-Ray Diffraction and Raman Spectroscopy.
Bob He 1 , Chris Frampton 2 , Juergen Sawatzki 3 Show Abstract
1 , Bruker AXS, Madison, Wisconsin, United States, 2 , Pharmorphix Ltd, Cambridge United Kingdom, 3 , Bruker Optics, Ettlingen Germany
Combinatorial material investigations require rapid screening techniques to test and evaluate variations of composition, structure and property within a material library. X-ray diffraction provides information on the atomic arrangement, microstructure and defects of a solid or liquid material. Raman spectroscopy measures the characteristic vibration frequencies determined by the chemical composition and chemical bond. Both X-ray diffraction and Raman spectroscopy are non destructive methods that require virtually no special sample preparation, thus, very suitable to analyze samples in a material or device library in its original form, which is typically determined by the particular combinatorial process. A two-dimensional diffraction pattern contains far more information than a one-dimensional diffraction profile collected with a conventional diffractometer. In recent years, usage of two-dimensional diffractometer has dramatically increased in academic researches and various industries due to abundant innovations in high brilliance X-ray source, high speed and high sensitivity area detectors and fast computers. Therefore, two-dimensional x-ray diffraction is an ideal characterization method for high-throughput screening of material or device libraries containing all kinds of samples, such as metals, polymers, ceramics, semiconductors, thin films, coatings, paints, biomaterials and composites, especially samples with small volume, micro-area and/or anisotropic microstructure, which are typical cases for combinatorial screening. The addition of Raman spectroscopy provides even better discrimination in high-throughput screening process in cases where the X-ray diffraction data are ambiguous. While X-ray diffraction characterizes a sample with phase identification, crystal size, orientation distribution and stress, Raman spectroscopy provides complementary information about chemical bond and molecular structure. A combined instrument with both X-ray diffraction and Raman spectroscopy capabilities is very beneficial to high-throughput combinatorial screening in advanced materials research, pharmaceutical development and catalyst discovery. This presentation covers the development of an innovative instrument consisting of two-dimensional X-ray diffraction and Raman spectroscopy for combinatorial screening as well as some application examples.
10:15 AM - A2.4
Electrochemical Study of Nano-interdigitated Electrode Structures Fabricated by EBL and NIL.
Lars Henrik Skjolding 1 2 3 , Christer Spegel 2 , Jenny Emneus 2 3 , Lars Montelius 1 Show Abstract
1 Division of Solid State Physics, Lund University, Lund Sweden, 2 Department of Analytical Chemistry, Lund Univesity , Lund Sweden, 3 MIC - Institute of Micro and Nano Technology, Technical University of Denmark, Lyngby Denmark
11:00 AM - A2.5
Rapid Characterization of CVD Oxide Films Using µHotplate Platforms.
Joshua Hertz 1 , David Lahr 1 , Jon Evju 1 , Steve Semancik 1 Show Abstract
1 Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
11:15 AM - A2.6
Evolved Wavelets for Analysis of Controlled Plasma Transients: Progress Towards Optimal Comparative Algorithms.
Terence Yeoh 1 , Genghmun Eng 1 , Maribeth Mason 1 , Gary Stupian 1 , Matthew Begert 2 Show Abstract
1 Microelectronics Technology Department, The Aerospace Corporation, El Segundo, California, United States, 2 National Law Enforcement Center West, The Aerospace Corporation, El Segund, California, United States
Wavelet analysis has considerable advantages over traditional Fourier methods for data reduction and in supporting ab initio simulations of materials properties. However, the fidelity of the analysis depends heavily on the initial wavelet function and the data to be modeled. Often, the dataset cannot be easily compressed and analyzed due to the extreme fidelity needed in order to characterize the details of the waveform. Plasma transients from controlled electrical impulses are complex waveforms with important features in both the high frequency, low amplitude domains as well as in the low frequency, high amplitude domains. The wide dynamics range of features and frequencies makes it difficult to find the function that models the entire dataset of transients. Evolved wavelet transforms have been extensively applied to image compression, however little work has been done to apply evolved wavelets on complex waveforms that describe non-linear materials properties. This paper describes the use of comparative algorithms that combine non-standard wavelet bases via genetic optimization and a unique self-comparison technique that allows us to self-derive the underlying waveform. By utilizing this technique, large numbers of datasets can be quickly compared and the important features extracted. These algorithms can be readily applied to a wide range of materials problems in order to quickly characterize and determine the key differences between large numbers of datasets.
11:30 AM - A2.7
Apparatus for Parallel Screening of PEM Fuel Cell Anode Catalysts.
Maxim Lobovsky 1 5 , John Gregoire 2 , Jing Jin 3 , Michele Tague 3 , Michael Heinz 1 , Hector Abruna 3 5 , Frank DiSalvo 3 5 , Robert van Dover 4 5 Show Abstract
1 Applied and Engineering Physics, Cornell University, Ithaca, New York, United States, 5 Cornell Fuel Cell Institute, Cornell University, Ithaca, New York, United States, 2 Physics, Cornell University, Ithaca, New York, United States, 3 Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States, 4 Materials Science and Engineering, Cornell University, Ithaca, New York, United States
11:45 AM - **A2.8
Micro-reaction Technique for Formation of Nano-sized Particulate Materials.
Hideaki Maeda 1 2 3 , Hiroyuki Nakamura 1 , Masato Uehara 1 Show Abstract
1 , Nanotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tosu, Saga, Japan, 2 Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, , Fukuoka, Japan, 3 , Japan Science and Technology Agency (JST), Core Research for Evolutional Science and Technology (CREST), 4-1-8 Hon-chou, Kawaguchi, Saitama, Japan
12:15 PM - A2.9
Block Copolymer Synthesis, Self-assembly, and On-line Monitoring of Micelles Using an Integrated Microfluidic System.
Kazunori Iida 1 , Thomas Chastek 1 , Michael Fasolka 1 , Kathryn Beers 1 Show Abstract
1 Polymers , National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Microfluidic technology is a promising platform for the high-throughput analysis of chemical reactions and liquid product formulations. In this sense, microfluidic technology appropriate for organic chemical reactions and processes at elevated temperatures represent an important advance. To address these needs, we are designing microfluidic devices that consist of machined aluminum plates sealed with thin polyimide films; these devices are stable in organic solvents at temperatures up to 100 °C for more than 24 hours. In addition, our devices incorporate online dynamic light scattering (DLS) measurements via fiber optic probes. In this presentation, we demonstrate the utility of the continuous synthesis of block copolymers on the device. Microfluidic atom transfer radical polymerization (ATRP) of styrene and (meth)acrylate derivatives were conducted on the device to obtain the desired homo- and block-copolymers with excellent control of molecular weight. The resulting reaction mixture was diluted subsequently with selective solvent to form micelles on the device. The microfluidic DLS on the device showed that block copolymer micelles were forming, and also indicated ratio of each segment affected the state of their miceller aggregation.
12:30 PM - A2.10
Complex Fluids Developed with Automated Combinatorial Processing.
Michael Grove 1 , Don Hayes 1 , Virang Shah 1 Show Abstract
1 , MicroFab Technologies, Inc., Plano, Texas, United States
Digitally-driven combinatorial processing of formulated fluids used as flavor additives in industrially prepared food products can now enable a significantly higher-throughput in the research and development of flavorant libraries. Although not typically recognized as a combinatorial chemistry process, development of flavor in commestibles has been so for centuries. Research and development of stable, flavorant approved organic chemicals in the 20th Century provided the food industry with a set of compounds that have been used to mimic the fugitive flavors of freshly prepared foods over the longer time span required of factory to distribution warehouse to consumer rather than the trip from a master chef's stove to a restaurant's table.Formulation of a fluid that is intended to be a flavor component in a food product of a major international food and beverage company, or a small, local company, begins with the selection of compounds based on a library of historical information that indicates their suitability to mimic the desired flavor. Laboratory work normally occurs at bench level. Compounds are measured in multiple milligram amounts and added to a base fluid that is compatible with the intended product. As the compounds will be present in the final product at the ppm level, significant dilution must occur from a volume of perhaps 0.1 L of base fluid to a test sample of a food or beverage product. Possibly only three compounds might be required to mimic a flavor, but five or more could be required. To prepare the possible combinations of the different organic flavor compounds at multiple concentrations of each, compound them into the final food product, and have the results analyzed by taste experts, is time consuming and expensive. This is not a high-throughput process.A new method has been being developed to automate the formulation of complex flavor fluids that enables high-throughput screening of new food flavors. Using ink jet dispensing technology that can accurately dispense picogram amounts of flavor compounds and micro-scale mixing technology, a combinatorial approach to sample preparation can allow an order of magnitude greater number of test samples to be evaluated in the same day. By enabling the incorporation of a dozen or more different organic compounds in a complex fluid mixture, which can be done with ink jet technology as easily as incorporating three, a researcher can easily prepare a library of flavor compounds of greater value than those currently existing that better mimics nature, which uses dozens of compounds for its flavors and aromas in fruits and vegetables.
12:45 PM - A2.11
Micro-PIV Using Novel Fluorescent Droplet Emulsions for Micro-fluidics Applications.
David Mendels 1 , Andres Muniz-Piniella 1 , Mourad Chennaoui 2 , Anita Jones 2 Show Abstract
1 I2D, National Physical Laboratory, Teddington, Surrey, United Kingdom, 2 Collaborative Optical Spectroscopy, Micromanipulation and Imaging Centre (COSMIC) and the School of Chemistry, The University of Edinburgh, Edinburgh United Kingdom
Micro-Particle Imaging Velocimetry (μPIV) has gained widespread acceptance since its inception as a robust mean to measure the in-plane components of the velocity of a fluid flowing down micro-channels of various shapes. This measurement consists of following the path of micro-particles seeded in the carrying fluid, the velocity being extracted through a digital image correlation approach. Because the average downstream velocities are usually high due to the small cross-sectional areas of channels, a stroboscopic measurement method is used. The image of a pulsed light source emission from the sample is captured through a gated high intensity CCD-camera. Monodisperse solid particles –latex, polystyrene, 1 to 5μm diameter- coated with a fluorescent dye are generally used to obtain a good contrast and facilitate image treatment.From an experimental point of view, the large volume fraction of particles often leads to clogging of microfluidic devices, and particles also tend to adsorb onto surfaces of the channels, where they cannot be removed easily. To reduce uncertainties, the particles should have a density close to the carrying fluid which avoids buoyancy effects: these appear to be important for low flow rates, even for latex in water. Additionally, the velocity of the fluid should be calculated from the velocity of the particle using a correction based on the volume of fluid displaced by the moving particle.To overcome these problems, we propose to use an emulsion of fluorescent droplets instead of solid particles. In this work, an oil in water emulsion was prepared where the dispersed phase (DMSO - Dimethyl sulfoxide) was doped with DCM dye (4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran, 10-2M), in silicon oil (PDMS, 50cS). This emulsion was stable over several hours, the size distribution being controlled within better than 0.5μm, and was rinsed easily, leaving clean channels for further use. Buoyancy effects were experimentally confirmed as negligible because of the similar values of densities of the fluid and the fluorescent droplets being very close. A droplet in the measurement plane of the μPIV apparatus remained in this plane while it travelled across the whole field of view. The signal to noise ratio was improved by several orders of magnitude, leading to more accurate measurements as the number of droplets needed in an interrogation area decreases. These benefits, together with their application to the measurement of low flow rates phenomena such as pump stability, will be presented in this paper.This research was carried out as part of the "Measurement for Emerging Technologies" programme funded by the National Measurement Systems Directorate of the UK Department of Trade and Industry, and was supported by the EPSRC Insight Faraday Partnership SHEFC.
A3: Infomatics and Library Design
Wednesday PM, November 28, 2007
Independence E (Sheraton)
2:30 PM - **A3.1
Tools for Expressing and Exploring Combinatorial Data.
Wesley Jones 1 , Daniel Korytina 1 , Peter Graf 1 Show Abstract
1 Scientific Computing Center, NREL, Golden, Colorado, United States
Scientific techniques and methods that rely on the relationships of collections of diverse, complex, arbitrary sets of data require tools for making connections and exploring those relationships. We will discuss a framework and tool set, OpenMAT, for transforming arbitrary scientific data sets into a hierarchical format for scientific data, expressing this format in a database, and overlaying its information to enable query by an arbitrary search tool and export for use by analysis tools. Key components of the system include: 1) a tool kit for ingesting arbitrary scientific data, automated metadata extraction, and instantiation in a hierarchical format, 2) software for automated expression and overlaying of data from the hierarchical format into a database, 3) a web-based interface for browsing, constructing arbitrary searches, and exporting data for further analysis. Key qualities of the system include: 1) the ability to collect and express data in a database without human intervention, 2) the ability to combine data from many different and varying sources into a single data repository for exploration by researchers, 3) open source underlying technologies, allowing for use of the system by a diverse set of collaborators.
3:00 PM - A3.2
Rapid Structural Mapping of Ternary Metallic Alloy Systems Using the Combinatorial Approach and Cluster Analysis.
Christian Long 1 , Jason Hattrick-Simpers 1 , Makoto Murakami 1 , Ramesh Srivastava 1 , Ichiro Takeuchi 1 , Xiang Li 2 , Vicky Karen 2 Show Abstract
1 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States, 2 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States
In order to map out the distribution of crystal structures in compositional phase diagrams, we have used clustering techniques on x-ray microdiffraction data from a library of thin film samples made using the combinatorial approach. These techniques allow us to group the samples according to their structure and plot the distribution of groups on the phase diagram. In addition to uncovering the distribution of structures on the phase diagram, this process aids in the identification of structural phases by reducing the number of spectra which must be analyzed from a number on the order of the number of samples (100s) on each library wafer to a number on the order of the number of unique structural phases. After the number of spectra is reduced to a few representative patterns, the main diffraction peaks of each pattern are matched up against those of known phases in the NIST crystallographic database. We will present an overview of the techniques and software used in our analysis. Example ternary systems include Fe-Pd-Ga.
3:15 PM - A3.3
Predicting Multi-component Crystal Structures Using Data Mining and Quantum Mechanics.
Geoffroy Hautier 1 , Chris Fischer 1 , Gerbrand Ceder 1 Show Abstract
1 , Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
Crystal structure prediction is a key problem in computational materials science.Although material property predictions can now be reliably addressed ab initio, for predictions to be relevant, they must be performed on the stable structure of the system.Predicting crystal structure is therefore an essential step in any computational materials design scheme.We have developed a method to predict the structure of multi-component systems using data mining and quantum mechanics.We demonstrate an algorithm that detects similarities between crystal structure in order to find the structure prototypes in any database.Correlations present in nature between prototypes can then be used to predict structure.The results of our prototyping and data mining algorithm applied to the Inorganic Crystal Structure Database (ICSD) are discussed.
3:30 PM - A3.4
Application and Development of Advanced Image Processing Algorithms for Automated Analysis of Serial Section Image Data.
Jeff Simmons 1 , Peter Chuang 2 , Mary Comer 2 , Michael Uchic 1 , Jonathan E. Spowart 1 Show Abstract
1 , AFRL, Dayton, Ohio, United States, 2 Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana, United States
Fueled by the integration of computer controls and the increase in detector capacity, modern microscopes are producing serial section image information at a rate that outpaces the human resources on any given project to fully analyze the data. It appears that data collection is limited by two factors: the ability to analyze and readily store data. Early trends in dataset size in our laboratory indicates that dataset sizes were roughly doubling every year, with current dataset sizes being on the order of 8-10GB. These datasets typically consist of hundreds of images or image montages, sometimes including information from multiple signal sources, such as alternate imaging conditions, chemical spectra, or crystallographic indexing. In order to be used in property simulations, image data must be converted to feature-based representations of grains, particles, laths, and the like. Historically, the supervised image processing techniques developed in the 1970's have been used in order to extract features of interest. In order to keep pace with the production of image data, we have turned to algorithms requiring minimal supervision such as those developed for computer vision applications in the 1990's. This work gives the results of several of these applications towards feature extraction from serial section image stacks of metallic systems. Results of these algorithms will be given and discussed.
3:45 PM - A3.5
High Throughput in Silico Materials Characterization Techniques using a Data Pipelining Environment.
Michael Doyle 1 , George Fitzgerald 1 , David Nicolaides 1 , Max Petersen 1 Show Abstract
1 , Accelrys, Inc., San Diego, California, United States
Computational techniques have been successfully used to predict an impressive array of physical and chemical properties of complex and diverse classes of materials. But when it comes to systematically designing and tailoring these material properties, often only a very limited part of the configuration design space can be computationally explored. Virtual high throughput screening is usually hindered by the fact that scaling up those calculations to a very large number of compounds creates severe challenges not only in the set-up and execution of the simulations, but also in data management and information accumulation tasks.This presentation introduces a computational approach in which industry accepted modeling tools, previously available in Accelrys’ Materials Studio, are implemented within a data pipelining environment. This data pipelining environment, Pipeline Pilot, captures reoccurring workflows in computational research applications. It integrates a variety of applications, streamlining their execution and facilitating their analysis. Furthermore, these workflows can be deployed as web-services. This approach lends itself ideally to studies were QSAR relationships are explored and applied. As an example we review how pKa predictions based on molecular fingerprints can be improved using quantum mechanical descriptors. Next, we illustrate how this platform can be used to analyze X-ray results generated in high-throughput crystallization experiments. Finally we demonstrate results from a computer experiment aimed at pre-selecting optimal solvent formulations for the dissolution of drug-like molecules.
4:15 PM - **A3.6
The Accelerated Discovery and Optimisation of New Materials:A High Throughput Thin Film Methodology.
Brian Hayden 1 2 Show Abstract
1 Chemistry, University of Southampton, Southampton United Kingdom, 2 , Ilika Technologies Ltd., Southampton United Kingdom
A new High-Throughput thin film Physical Vapour Deposition (HT-PVD) method based on Molecular Beam Epitaxy sources which allows the controlled synthesis of compositionally varying solid state materials  is described. The synthesis allows not only large compositional ranges of pure materials to be synthesised, and subsequently screened, but it also provides through the simultaneous combination of the elements a unique synthetic route to solid state materials including mixed oxides, hydrides and nitrides. These materials are ideal for parallel or fast sequential screening in continuous film form, or masked on dedicated micro-fabricated MEMS screening arrays. Parallel or automated sequential characterisation methods have also been optimised for the materials. The application of the HT-PVD synthesis, characterisation and screening methods will be exemplified using examples from applications in the electronics and energy sectors. In the former, the synthesis, primary and secondary screening of chalcogenide phase change memory materials  will be outlined, as well as the synthesis of perovskite piezoelectric materials . Programmes to discover new metal hydride hydrogen storage materials  and platinum lean or free fuel cell electrocatalysts  will provide examples of the application of the technology to the energy sector. Benchmark experiments will be described in order to demonstrate the validity of the discovery methodology.1. Samuel Guerin and Brian E. Hayden; J. Comb. Chem 2006, 8, (1), 66-73.2. Robert E Simpson, Dan W Hewak, Samuel Guerin, Brian E. Hayden and Graeme Purdy; Proceedings of European Symposium on Phase Change and Ovonic Science (E*PCOS), Cambridge (2005).3. P.S.Anderson, S.Guerin, B.Hayden, M.A.Khan, A.J.Bell, Y.Han, M.Pasha, K.R.Whittle and I.M.Reaney; Applied Physics Letters 90 (2007) 202907. 4. Samuel Guerin, Brian Hayden and Duncan Smith; J. Comb. Chem. (in preparation).5. Samuel Guerin, Brian E. Hayden, Christopher E. Lee, Claire Mormiche, Andrea E. Russell; J.Phys.Chem.B 110 (2006) 14355-14362.Brian E. Hayden, Derek Pletcher and Jens-Peter Suchsland; Angewandte Chemie Int. Ed. 46 (2007) 3530-3532.
4:45 PM - A3.7
High-throughput Sample Preparation for Transmission Electron Microscopy.
Michael Fasolka 1 , Brian Berry 1 , Kristen Roskov 1 , Thomas Epps 2 Show Abstract
1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 2 Department of Chemical Engineering, University of Delaware, Newark, Delaware, United States
We present a new method for harvesting multiple thin film specimens from polymer combinatorial libraries for Transmission Electron Microscopy (TEM) analysis. Such methods are of interest to researchers who wish to integrate TEM measurements into a combinatorial or high-throughput experimental workflow. Our technique employs poly(acrylic acid) plugs, sequestered in an elastomer gasket, to extract a series of film patches from gradient combinatorial arrays. A strategy for simultaneously depositing the array of film specimens onto TEM grids is also described. We demonstrate our technique using nanostructured block copolymer thin film libraries as a test case.
5:00 PM - A3.8
Linear Combinatorial Approach to Thin Film Research.
Vladimir Matias 1 , Brady Gibbons 2 Show Abstract
1 Superconductivity Technology Center, Los Alamos National Laboratory, Los Alamos, New Mexico, United States, 2 Department of Mechanical Engineering, Oregon State University, Corvallis, Oregon, United States
We describe high-throughput experimentation of film synthesis by use of a linear tape transport system. Metal tape is fed continuously in a reel-to-reel transport system inside a vacuum deposition chamber. Ion-beam assisted deposition texturing is used to enable the growth of epitaxial films on flexible, polycrystalline metal tapes which further enhances the capability of this research. The tape that is continuously fed can be used as a sample itself, via the use of IBAD-textured templates on the tape, or can be a carrier of other smaller substrates (even non-flexible ones). Hundreds of synthesis experiments can be performed in one sequence on tens of meters of tape. Characterization of samples is done by means of in situ monitoring as well as ex situ sequential analysis. We utilize in situ reflection high-energy electron diffraction for high-throughput screening of samples. Epitaxial films are deposited on heated substrates by evaporation and by pulsed laser deposition. Here, we explain the unique techniques and methodologies developed for this type of combinatorial experimentation and show some examples of the materials research performed.This work is supported by the Department of Energy Office of Electricity Delivery & Energy Reliability.
5:15 PM - A3.9
Sputter Deposition System for High Throughput Fabrication of Composition Spreads.
John Gregoire 1 2 , Maxim Lobovsky 3 , Michael Heinz 3 , Hector Abruna 4 2 , Frank DiSalvo 4 2 , Bruce van Dover 5 2 Show Abstract
1 Physics, Cornell University, Ithaca, New York, United States, 2 Cornell Fuel Cell Institute, Cornell University, Ithaca, New York, United States, 3 Applied and Engineering Physics, Cornell University, Ithaca, New York, United States, 4 Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States, 5 Material Science and Engineering, Cornell University, Ithaca, New York, United States
We describe a custom built sputtering system that can deposit composition spreads in an effectively UHV environment but which does not require the high-throughput paradigm to be compromised by a long pumpdown each time a target is changed. The system employs four magnetron sputter guns in a cryoshroud (getter sputtering) which allows elements such as Ti and Zr to be deposited with minimal contamination by oxygen or other reactive background gasses. Other features of the deposition system will be presented, most notably the ability to quickly measure deposition profiles from individual deposition sources. We discuss the possibility of calculating codeposited film composition from these profiles, noting that codeposition affords resputtering phenomena which are absent in single-source deposition. To demonstrate the efficacy of this system, we describe our study of combinatorial libraries of electrocatalyst materials for fuel cell applications. This study includes a high-throughput parallel screening of composition spreads using a fluorescence indicator.
5:30 PM - A3.10
Miniature Pulsed Laser Deposition Systems for High-Throughput Thin Film Growth.
Mikk Lippmaa 1 , T. Ohnishi 1 , K. Itaka 2 , H. Koinuma 2 , T. Sato 3 Show Abstract
1 Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan, 2 Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba 277-8568, Japan, 3 , Vacuum Products Corporation, Tokyo, 187-0012, Japan
In solid-state synthesis of thin films it is rarely possible or even desirable to perform truly combinatorial experiments where a large number of constituent elements are mixed or layered in a particular order. In thin film experiments, achieving high experimental throughput generally has a higher priority. This can be achieved by designing samples for phase space or parameter space mapping, as in composition spreads, and also by increasing the turnaround time and cost of the thin film growth systems. To address such needs, we are developing miniaturethin film growth systems that still offer the basic components necessary for composition spread library growth. The chambers are designed for pulsed laser deposition of inorganic materials, use laser heating to achieve a wide film growth temperature range, and include in-situ electron diffraction for growth rate and surface morphology monitoring. The systems also include a multi-target stagefor manipulating 4 to 6 targets and a programmable shadow mask for depositing composition spread-type samples. The reduced chamber size can dramatically improve the experimental turnaround time and simplify the servicing of the deposition systems. An important part of combinatorial synthesis is the automation of the process control and the handling of all experiment-related data including library design, process control, characterization, and analysis. We discuss the integration of the thin film growth chambers into a database system for managing the whole experimental process.
David S. Ginley National Renewable Energy Laboratory
Michael J. Fasolka National Institute of Standards and Technology
Alfred Ludwig caesar, Bonn; Ruhr-Universitaet Bochum
Mikk Lippmaa Institute for Solid State Physics
A4: High Throughput for Polymers, Organics and Biomaterials
Thursday AM, November 29, 2007
Independence E (Sheraton)
9:00 AM - **A4.1
Modifying Physical Properties of Semi-crystalline Polymers through High Throughput Experimentation.
Hyeok Hahn 1 , Damian Hajduk 1 , Shaosheng Dong 1 , Ying Chen 1 Show Abstract
1 , Symyx Technologies Inc., Sunnyvale, California, United States
Ultimate mechanical strength and tensile ductility are two important criteria in choosing semi-crystalline polymeric materials for commercial applications. Leveraging high throughput techniques, we have demonstrated that it is possible to rapidly map out relationships between polymer composition, architecture, and mechanical properties. Physical blends and reactive blends of semi-crystalline polymers were prepared through high throughput micro-extrusion technique, processed into specimens, and characterized using high throughput tensile testing and melt rheology. Based on 500 new polymer blends, we have demonstrated that high throughput techniques are effective tools in unraveling the role of compositions and degree of compatibilization in modification of mechanical properties and thermal properties of semi-crystalline polymeric blends. In general, crystallization kinetics and tensile properties of blends were dictated by composition. We observed that samples prepared through reactive blending have faster crystallization kinetics and better tensile properties than samples prepared through physical blending.
9:30 AM - **A4.2
Microfluidic for Material HTS Characterization: Phase Diagram, Rheology, Calorimetry.
Mathieu Joanicot 1 Show Abstract
1 UMR 5258 - CNRS / Bordeaux 1 / Rhodia, Rhodia Lab of the Future, Pessac France
Microfluidics is a powerful and emerging technology for management of liquid samples at micro scale. It is now widely used for biological application and diagnostics. In some microfluidic schemes, nanoliter droplets of uniform size can spontaneously form in microchannels when two immiscible fluid streams merge.This new route for easy and steady production of calibrated emulsions and traffic control of the droplets open a stimulating field for application of microfluidic devices. These tiny droplets are almost ideal as chemical reactors for synthesis and for formulation and management of complex fluids. There are lots of potential applications, and we will specifically focus on: micro-rheology, micro calorimeter, phase diagram mapping. One could also see the main advantage of formulation and synthesis on a chip if evaluation of the product is integrated into a seamless process. This talk will discuss which analytical tool are available and what should be develop to run some real life formulation experiment on a chip form A to Z.
10:00 AM - A4.3
Synthesis and Optical Properties of Silver and Gold Coated Polymeric Micropheres and their use as SERS Substrate.
Abdiaziz Farah 2 1 , Ramon Alvarez-Puebla 2 , Juan Bravo-Vasquez 2 , Hicham Fenniri 2 1 Show Abstract
2 , National Institute For Nanotechnology, Edmonton, Alberta, Canada, 1 , Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
Surface-enhanced Raman scattering (SERS) using metal nanoparticles provides a powerful tool for investigating the chemical and biological micro-environments at the molecular level. 1, 2 We are currently developing chemically functionalized polymeric microspheres coated with metal nanoparticles. Our main objective is on integrating novel substrate synthesis and in situ metal deposition to create SERS-active polymeric micropheres to enable ultrasensitive analytical measurements. 3 Metal coated and moderately crosslinked functionalized microbeads as SERS active nanocomposites will be described. The nanocomposites were thoroughly characterized by (SEM, TEM, XPS, DSC, TGA, Raman and SERS) to elucidate their morphology, particle size, composition, thermal stability and their optical and electronic properties.1. (a) Aroca, R. F.; Alvarez-Puebla, R. A.; Pieczonka, N.; Cortez, S. S.; Garcia-Ramos, J. V. Advanced in Colloid and Interface Science 2005, 116, 45. (b) Aroca, R. Surface-Enhanced Vibrational Spectroscopy, Wiley, New York, 20062. Kniepp, K.; Kniepp, H.; Kniepp, J. Acc. Chem. Res. 2006, 39, 443-4503. Farah, A. A.; Alvarez-Puebla, R. A.; Bravo-Vasquez, J. P.; Cho. J-Y.; Fenniri, H. Small (submitted 2007)
10:15 AM - A4.4
Combinatorial Screening of Temperature on the Mobility and Structure of a High Performance Polythiophene Semiconductor.
Leah Lucas 1 , Dean DeLongchamp 2 , Brandon Vogel 2 , Eric Lin 2 , Michael Fasolka 2 , Daniel Fischer 2 , Iain McCulloch 3 , Martin Heeney 3 , Ghassan Jabbour 1 Show Abstract
1 School of Materials and Flexible Display Center, Arizona State University, Tempe, Arizona, United States, 2 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States, 3 , Merck Chemicals, Chilworth United Kingdom
Using a gradient combinatorial approach, we report the effects of temperature on the microstructure and hole mobility of poly(2,5-bis(3-dodecylthiophen-2yl)thieno[3,2-b]thiophene) thin films for application in organic thin film transistors. The gradient heating revealed a detailed dependence on thermal history. Optimal heat treatment achieved mobilities as high as 0.3 cm2/V●s. Mobility enhancement coincides with an increase in crystal domain size and orientation, all of which occur abruptly at a temperature closely corresponding to a bulk liquid crystal phase transition.
10:30 AM - A4.5
High-throughput Screening of EPM and EPDM Cross-linking.
Johannes Kranenburg 1 , Martin van Duin 2 , Ulrich Schubert 1 3 Show Abstract
1 Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology, Eindhoven Netherlands, 2 Performance Materials - Chemistry and Technology (PM-CT), DSM Research, Geleen Netherlands, 3 Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University, Jena Germany
During curing of ethylene-propylene rubber (EPM) or ethylene-propylene-diene rubber (EPDM), inter-chain cross-links are generated that give the EP(D)M its typical elastomeric mechanical behavior. Different grades of EPM and EPDM are available, and a variety of cross-linkers (for example: peroxides) and additional chemicals (coagentia) is used for curing. The crosslink density and the final properties depend on the types and amounts of peroxide and coagent used. The multitude of these variations in EPDM-types, curing systems and, in addition, curing conditions results in a large parameter space for optimization. High-throughput experimentation (HTE) can be very useful to explore this large parameter space.A solution route was developed that enabled high-throughput sample preparation. As starting materials, EPM and EPDM with and without carbon black and oil were used. Via this route, the desired formulations of starting material with cross-linker and coagens could be prepared. Curing of these formulations was performed via compression-molding, which is essentially similar to industrial practice. Depth-sensing indentation proved to be a suitable high-throughput method to investigate the state of cure, as shown by testing a reference set of vulcanizates. The indentation results correlate very well with Shore A hardness, and reasonably well with the modulus 100% and compression set. Also the samples prepared in a HTE approach were investigated by depth-sensing indentation. Further, the conversion of the EPDM unsaturation of these samples was measured using Raman-spectroscopy. Most obtained indentation and Raman-spectroscopy results agreed nicely with already existing knowledge on the effect of coagentia on EPDM curing efficiency; other results exhibited unexpected trends, inviting further investigation that may shed a new light on the effectivity of coagentia on the curing-process of EP(D)Ms.
10:45 AM - A4.6
Rapid Approach for Measuring Viscoelastic Properties of Confined Polymer Films.
Kirt Page 1 , Christopher Stafford 1 , Derek Patton 1 , Rui Huang 2 Show Abstract
1 Polymers Division, NIST, Gaithersburg, Maryland, United States, 2 Department of Aerospace Engineering and Engineering Mechanics, University of Texas, Austin, Texas, United States
In the past several years there have been a number of advances in the understanding of the physics of polymer thin films. However, there still remains a wide range of opportunities to further this understanding through the development of measurement tools capable of probing the physical properties (i.e., viscosity and modulus) of polymer films on the sub-micrometer size-scale. Our approach exploits a wrinkling instability that arises when a polymer film capped with a thin evaporated metal layer is heated. As the system is heated, stresses build up in the composite film due to mismatches in the coefficients of thermal expansion (CTE), which results in a regular sinusoidal wrinkling of the surface. The kinetics of this wrinkling process are dictated by a number of parameters, including the viscoelastic properties of the underlying polymer film. Our study demonstrates how the real-time observations of wrinking in the metal-polymer bilayer can be used to measure the viscoelastic behavior of the underlying polymer. In particular, surface small angle laser light scattering analysis allows us to track the time-dependent wrinkling amplitude and wavelength evolution as a function of annealing temperature. With this new, robust metrology, it is possible to measure the relaxation behavior of a variety of confined polymer systems including polymer brushes, polymer nanocomposite thin films, and block copolymers. By combining this metrology with a gradient sample approach, there is the potential of performing these measurements rapidly and on a large number of samples.
11:30 AM - **A4.7
Polymer Microarray Fabrication and Screening.
Mark Bradley 1 Show Abstract
1 , University of Edinburgh, Edinburgh United Kingdom
Polymers are essential in the area of biomaterials and have been used in a myriad of applications. The mechanism of cell immobilization onto polymer surfaces in cell culture has been extensively studied and it is broadly accepted that the first steps in this process are the adsorption of extracellular matrix proteins onto the surface of the polymer. Cells then indirectly interact with the polymer through the adsorbed proteins which control a variety of cellular processes such as adhesion, growth and differentiation. As a result of such complex and imperfectly understood interactions, it is still impossible to predict, from the chemical structures of a polymer, how such materials will perform when in contact with cells, blood or body fluids. As a consequence, the use of a high-throughput approach to allow the rapid synthesis of chemically diverse polymers offers an important tool to be able to find correlations between the design and performance of such materials. Traditional methods of synthesis, identification and testing of new polymers are slow and thus over recent years, the field of automated and parallel synthesis of polymers has grown enormously , but, as is usually the case in any HT process, the development of high-throughput characterization and screening methods are often the rate limiting steps. In this lecture a variety of approaches will be presented showing the preparation of a number of polymer based microarray platforms and their application in a number of cell based screens. Synthesis will include both contact and inkjet printing of pre-formed polymers, inkjet blending of pre-formed polymers as well as direct inkjet based polymer synthesis.
12:00 PM - **A4.8
Characterization of Functional Biomaterials using Combinatorial Approaches.
Matthew Becker 1 Show Abstract
1 Polymers Division, NIST, Gaithersburg United States
Despite tremendous investment, the translation of functional tissue engineering products to the clinic has been extremely slow. Many of the problems have arisen in the developmental process due to fundamental knowledge gaps in what kinds of material properties are necessary to stimulate a desired response. In addition, substrate independent methods and tools for characterizing functional materials are inadequate in the sense that they are often bulk measurements and are not capable of providing spatial information on the presence and accessibility of functional species. New approaches which afford systematic and rapid elucidation of functional elements at the interface of organic and inorganic materials are critical to the materials optimization processes inherent in early research and development phases of product development. The ability to characterize and discriminate small differences in functionality between closely related materials is important to applications where high levels of bio-activity are needed while excessive amounts cause adverse biological effects. Further separating the lab from the clinic is that most combinatorial efforts rely on automated data collection of endpoint assays done on thin films while materials typically experience dynamic 3D environments in vivo. Recently, we and others have placed increased emphasis on developing combinatorial and continuous variable gradient sample fabrication methods which cover large areas of phase space in both 2D and 3D. We are using these substrates to narrow the potential phase space and identify regions where favorable interfacial interactions are occurring. While far from a complete story, this presentation aims to detail our methods and ongoing results using several approaches to measure ligand density effects, bio-mineral polymorphs, and compositional profiles in polymeric materials.
12:30 PM - A4.9
High-Throughput Bioadhesion Measurements Using a JKR Contact Apparatus.
Adam Nolte 1 , Heqing Huang 1 , Christopher Stafford 1 Show Abstract
1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
We demonstrate how the method of Johnson, Kendall and Roberts (JKR) can be used for high-throughput testing of biomolecular adhesion. Our measurements are performed by contacting a macroscopic hemispherical lens with a substrate of interest. In this work, we introduce a new method of lens functionalization that utilizes layer-by-layer assembly of polyelectrolytes and proteins to create model biosurfaces. In addition, we introduce combinatorial methods to fabricate substrates with gradient libraries of surface energy and roughness. Conducting JKR measurements using the biofunctionalized lens in combination with the substrate library allowed us to rapidly assess biomolecular adhesion as a function of governing surface parameters. In addition to presenting these results, we discuss future challenges and strategies for these types of measurements in aqueous solutions mimicking biological environments.
12:45 PM - A4.10
Deconvolution of Self-encoded Polymer Beads in Random Microarrays for Antigen Biosensing by Raman Spectroscopy.
Juan Bravo-Vasquez 1 , Ramon Alvarez-Puebla 1 , Hicham Fenniri 1 2 Show Abstract
1 , National Institute for Nanotechnology, Edmonton, Alberta, Canada, 2 Chemistry, University of Alberta, Edmonton, Alberta, Canada
A5: Combinatorial Electronics and Oxides
Thursday PM, November 29, 2007
Independence E (Sheraton)
2:30 PM - **A5.1
Combinatorial Development of Amorphous Mixed Metal OxideTransparent Conductors.
John Perkins 1 , Maikel van Hest 1 , Joseph Berry 1 , Jeff Alleman 1 , Matthew Dabney 1 , Lynn Gedvilas 1 , Brian Keyes 1 , David Ginley 1 Show Abstract
1 National Center for Photovoltaics, National Renewable Energy Laboratory, Golden, Colorado, United States
Amorphous In-Zn-O (a-IZO) is the archetype of a new class of amorphous mixed metal oxide materials which are becoming both the transparent conducting oxide (TCO) of choice for contact applications such as flat panel displays and, as a channel layer material, enabling a new generation of transparent thin film transistors. We are using combinatorial and conventional approaches to optimize a-IZO for both of these applications. The compositionally-graded combinatorial samples (“libraries”) are deposited by co-sputtering onto 2”x2” glass substrates. Three to five libraries are generally required to cover the full composition range for a binary tie-line. The libraries are characterized by a variety of automated combinatorial mapping tools including EPMA for metals stoichiometry, 4-pt. probe for sheet resistance, UV/VIS/NIR (200-2000 nm) reflection and transmission, FTIR optical reflection and transmission (1800 – 25000 nm), x-ray diffraction (XRD) using a large area 2D detector and work function mapping. By varying the metals composition, oxygen partial pressure during deposition, substrate temperature, and post-deposition annealing, we can control the a-IZO conductivity across eight orders of magnitude and thereby optimize a-IZO for either high conductivity transparent electrical contact and low conductivity transistor channel layer applications. We will also show how the use of combinatorial approaches led to new discoveries and hence understanding about the In-Zn-O materials that would likely not have been developed by conventional approaches.
3:00 PM - **A5.2
Combinatorial Approach for Ferroelectric Material Libraries Prepared by Liquid Source Misted Chemical Deposition Methode.
Seong Ihl Woo 1 , Ki Woong Kim 1 , Min Ku Jeon 1 , Kwang Seok Oh 1 , Tai Suk Kim 1 , Yun Seok Kim 1 Show Abstract
1 Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon Korea (the Republic of)
Combinatorial approach for discovering novel functional materials in the huge diversity of chemical composition and processing conditions has become more important for breakthrough in thin film electronic and energy-conversion devices. The efficiency of combinatorial method depends on the preparation of a reliable high-density composition thin-film library. The physico-chemical properties of each sample on the library should be similar to those of the corresponding samples prepared by one-by-one conventional methods. We successfully developed the combinatorial liquid source misted chemical deposition (LSMCD) method and demonstrated its validity in screening the chemical composition of Bi3.75LaxCe0.25-xTi3O12 (BLCT) for high remanent polarization (Pr). LSMCD is a cheap promising combinatorial screening tool. It can control the composition up to ppm level and produce homogeneous multi-component library. A BLCT (0 ≤ x ≤ 0.25) thin-film library was prepared by LSMCD equipped automated shutter. The chemical compositions of BLCT samples on the library were measured by wavelength dispersive spectroscopy and the thicknesses of each sample on the library were measured by SEM cross-section image. LSMCD method allows us to prepare BLCT thin-film library at the variation of 0.4 mol% of La and thicknesses of 200 nm ± 10 nm. Maximum 2Pr is 35 μC/cm2 at x = 0.21. The intensity of (117) XRD peak is quantitatively related to 2Pr. Newly developed scanning piezoelectric deformation measurement for nano-sized samples using scanning probe microscope (SPM) is also found out to be reliable for determining the relative ranking of Pr value rapidly.
3:30 PM - A5.3
Determination of Work Functions in the Ta1-xAlxNy/HfO2 Advanced Gate Stack Using Combinatorial Methodology.
Kao-Shuo Chang 1 2 , Martin Green 1 , John Suehle 1 , Jason Hattrick-Simpers 2 , Ichiro Takeuchi 2 , Stefan De Gendt 3 Show Abstract
1 , NIST, Gaithersburg, Maryland, United States, 2 Department of Materials, University of Maryland, College Park, Maryland, United States, 3 , IMEC, Leuven Belgium
Aggressive scaling of complimentary metal-oxide-semiconductor (CMOS) transistors has made the traditional gate stack, SiO2 gate dielectric and polycrystalline Si (poly-Si) gate electrode, unsuitable for future integrated circuits. High leakage current density (JL), poly-Si depletion, and boron dopant diffusion are the most urgent gate stack problems to be solved. In the past decade, high-k gate dielectrics such as HfO2, Hf-Si-O, and Hf-Si-O-N have been identified as promising replacements for SiO2. However, selection of metal gate substitutes for poly-Si are not as advanced. For CMOS applications, the metal gate electrodes must have work functions (Φm) aligned with the conduction (4.05 ± 0.2 eV) and valence (5.17 ± 0.2 eV) bands of Si, for NMOS and PMOS applications, respectively. Among the many metal gate candidates, TaNy has shown very useful Φm tunability by alloying with various elements. In particular, Ta1-xAlxNy alloys are easily formed, with very good electrical and chemical properties. However, the systematic measurement of Φm across the wide composition range of Ta1-xAlxNy alloys is not trivial, since capacitor fabrication and characterization based on a one-composition-at-a-time approach is extremely time consuming. Combinatorial methodology enables the generation of a much more comprehensive and uniform data set, since it allows high throughput measurements on a “library” film that contains the entire compositional variation. In this talk we will demonstrate the efficacy of combinatorial techniques for the rapid determination of Φm of Ta1-xAlxNy metal gate alloys, through the deposition of a binary composition spread.A linear variation and wide range of Ta1-xAlxNy compositions were achieved. The equivalent oxide thickness (EOT) maps indicated strong thermal resistance and robust electrical characteristics. Vfb was extracted from the capacitance-voltage (C-V) curves to determine Φm and Qf. The values of Φm, from ~ 5.1 eV for the Ta0.95Al0.05Nx alloys to ~ 4.9 eV for the Ta0.5Al0.5Nx alloys, suggested a good replacement for polysilicon in the advanced gate stacks. We have, for the first time, systematically extracted Φm as a function of composition for almost the entire Ta1-xAlxNy/HfO2 advanced gate stack under forming gas anneal (FGA), 900°C and 1000°C thermal budgets.
3:45 PM - A5.4
Combinatorial Study of the Crystallinity Boundary in the HfO2-TiO2-Y2O3 System using Pulsed Laser Deposition Library Films.
Jennifer Ruglovsky 1 , Nabil Bassim 1 , Peter Burke 1 , Peter Schenck 1 , Martin Green 1 Show Abstract
1 , National Institute of Standards and Technology, Gaithersburg, Maryland, United States
We demonstrate that combinatorial methodology may be used as a tool for the metrology of crystallization boundaries in ternary thin films. The HfO2-TiO2-Y2O3 ternary thin film system was realized via combinatorial Pulsed Laser Deposition (PLD) at several substrate temperatures from 300°C to 700°C. In the higher temperature library films (≥400°C) a visible boundary line was observed across the sample due to an abrupt change in the refractive index. Inspection via mapping x-ray diffraction confirms that the line separates crystallized from amorphous regions of the film, where the amorphous region is the corner of the ternary with the Ti-rich composition. Simulations indicate that the crystalline boundary line appears to track a constant-composition line of TiO2. With libraries grown at increasing temperatures, we observed that the boundary moves toward the Ti-rich region, as more of the film becomes crystalline. Incorporating more TiO2 into the film, by altering the deposition parameters, results in the boundary moving further into the HfO2-Y2O3 region. Results from an industrially standard rapid thermal anneal (RTA) of the library films will also be discussed. Our experiments on a technologically relevant high-k system offer insight into the thermal stability necessary for advanced device applications.
4:45 PM - A5.6
ITO-Nanocomposite Thin Film Strain Gages with Low TCR.
Otto Gregory 1 , Ximing Chen 1 Show Abstract
1 Department of Chemical Engineering, University of Rhode Island, Kingston, Rhode Island, United States
5:00 PM - A5.7
A Combinatorial Approach to Studying Intrinsic and Extrinsic n-type ZnO.
Steven Kirby 1 , R. van Dover 1 Show Abstract
1 Material Science and Engineering, Cornell University, Ithaca, New York, United States
Improved transparent conductors are essential to drive costs down in flat panel display and photovoltaic technology. The combinatorial work to date has focused on finding new wide band gap materials to replace existing transparent conductors. This study uses a combinatorial approach to investigate the effects of dopants in ZnO including the effect of co-doping with more than one n-type dopant. We use magnetron cosputtering with up to three 2-inch 90° off-axis rf sputter guns along with one on-axis 4-inch sputter gun. A 4-inch Zn target can be sputtered reactively on axis to achieve a uniform ZnO deposition rate on the substrate. Up to three dopants can be cosputtered using the off-axis guns to achieve a large range of dopant concentration on a single substrate in a single deposition. The films are analyzed using XRD, electron microprobe, four-point resistivity probe, Hall effect, and reflection and transmission spectroscopy at optical wavelengths. A 2-inch elemental Zn target can be mounted in the off-axis configuration to allow the study of oxygen vacancies and other intrinsic defects, since the presence of intrinsic defects strongly depends on deposition rate (which varies with distance from target in off-axis sputtering). Regions close to the target have a higher defect density due to higher deposition rate. The defects create free carriers, and can very the conductivity of undoped ZnO by more than an order of magnitude across a substrate. This represents a powerful combinatorial method for studying the effects of intrinsic defects on the properties of ZnO.
5:15 PM - A5.8
Origin of Suprexchange Ferromagnetism: Evaluations of Ni and Mn Valencies in a LaNiO3-LaMnO3 Composition Spread Thin Film by X-ray Absorption Spectroscopy.
Isao Ohkubo 1 , Miho Kitamura 1 , Toshihiro Ishihara 1 , Koji Horiba 1 , Hiroshi Kumigashira 1 4 , Yuji Matsumoto 2 , Hideomi Koinuma 3 4 , Masaharu Oshima 1 4 Show Abstract
1 Dept. of Applied Chemistry, The University of Tokyo, Tokyo Japan, 4 CREST, Japan Science & Technology Corporation (JST), Tokyo Japan, 2 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama Japan, 3 Graduate School for Frontier Sciences, The University of Tokyo, Kashiwa Japan
5:30 PM - A5.9
Electronic State Characterizations of LaNiO3-LaMnO3 Composition Spread Flms using Synchrotron-radiation Photoemission Spectroscopy.
Miho Kitamura 1 , Isao Ohkubo 1 , Toshihiro Ishihara 1 , Koji Horiba 1 4 , Hiroshi Kumigashira 1 4 , Yuji Matsumoto 2 4 , Hideomi Koinuma 3 4 , Masaharu Oshima 1 4 Show Abstract
1 Department of Applied Chemistry, The University of Tokyo, Tokyo Japan, 4 CREST, Japan Science & Technology Corporation (JST), Tokyo Japan, 2 Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama Japan, 3 Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa Japan
Perovskite oxides have attracted great interest because of their remarkable magnetic and transport properties, such as high-TC superconductivity, colossal magnetoresistance (CMR) and multiferroics. LaNiO3-LaMnO3 alloy system shows a metal-insulator transition from LaNiO3, a paramagnetic metal to LaMnO3, an antiferromagnetic insulator. Besides, La2NiMnO6 is a ferromagnetic semiconductor that has a ferromagnetic transition temperature near room temperature (TC ∼ 280 K). The ferromagnetism of LaNi1-xMnxO3 with x = 0.5 is explained by the mechanism due to a superexchange interaction in Ni-O-Mn bonds, which is predicted theoretically by Kanamori-Goodenough rules. However, the detailed magnetic and electric phase diagrams covering the whole composition range of LaNi1-xMnxO3 have not been obtained yet. Furthermore, fundamental understanding of its electronic states is necessary for device applications as a ferromagnetic semiconductor. In this study, combinatorial methods, enabling rapid fabrications and high-throughput analyses, were utilized to systematically evaluate electronic states of LaNi1-xMnxO3. We have developed a new continuous composition spread - pulsed laser deposition (CCS-PLD) system equipped with a moving-mirror which introduces ablation laser into the PLD chamber. This CCS-PLD system makes it possible to grow homogeneous films with relatively larger area (20 mm × 20 mm) than those grown by a conventional PLD. The electronic states were studied by combinatorial synchrotron-radiation photoemission spectroscopy (SR-PES).LaNiO3-LaMnO3 composition spread films were grown on LaAlO3 (100) substrates by CCS-PLD. The growth temperature and the oxygen ambient pressure were 600 °C and 100 mTorr, respectively. The films were characterized by X-ray fluorescence (XRF) and X-ray diffraction (XRD). SR-PES measurements were performed at KEK-PF BL-2C beamline to evaluate electronic states of LaNi1-xMnxO3. Temperature-dependent resistivity (ρ- T) measurements were done in the temperature range from 4 K to 300 K. XRF intensity maps of NiKα and MnKα show that the composition gradient in the films is obtained as designed. Epitaxial growth in the whole composition range of the films was confirmed by XRD patterns. Valence band (VB) PES spectra reveal that the density of state (DOS) at the Fermi level decreases with increasing the incorporated Mn into LaNiO3, indicating metal-insulator transition. This is in good agreement with the results of ρ- T measurements. In the insulating composition range (x = 0.3 ∼ 1), the energy levels of VB maxima remain unchanged irrespective of the composition ratio of Ni to Mn, as well as resistivities at room temperature. The details of valence band structures at each composition will be discussed.
5:45 PM - A5.10
Phase Relationships in the Ba-Y-Cu-O System Using the Combinatorial Approach.
Winnie Wong-Ng 1 , Makoto Otani 1 , Alex Shapiro 2 , Peter Schenck 1 , Igor Levin 1 , Lawrence Cook 1 , Martin Green 1 , Ron Feenstra 3 , H. Ohguchi 4 , Ichiro Takeuchi 4 Show Abstract
1 Ceramics, NIST, Gaithersburg, Maryland, United States, 2 Metallurgy, NIST, Gaithersburg, Maryland, United States, 3 Materials Science and Technology, ORNL, Oak Ridge, Tennessee, United States, 4 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States
A6: Poster Session: Combinatorial Materials Science
Friday AM, November 30, 2007
Exhibition Hall D (Hynes)
9:00 PM - A6.1
Fatigue in a Microcontact of a Brittle Material.
Yun Chen 1 , Kaloian Koynov 1 , Hans-Juergen Butt 1 Show Abstract
1 , Max-Planck-Institute for Polymer Research, Mainz Germany
9:00 PM - A6.10
Pt-based Binary-alloy Schottky Metal Library Fabrication for ZnO by Combinatorial Method.
Takahiro Nagata 1 , Michiko Yoshitake 1 , Janos Volk 1 , Toyohiro Chikyow 1 Show Abstract
1 Advanced Electric Materials Center, National Institute for Material Science, Tsukuba Japan
Zinc oxide (ZnO) has been attracting attention for use in light emitting and light detecting devices in the UV wavelength region. For these applications, high quality and thermally reliable Schottky contacts are inevitable. In this paper we have demonstrated hetero structures consisted of composition spread metal-alloys on ZnO and quick screening for their electrical properties with combinatorial alloy synthetic technique. The Schottky barrier height is related to the work function of metals. It is known that the work function is generally affected by a crystallogrhaic orientation of metal because each orientation of the metal has a different surface potential. Additionally, the work function is dependent on interface structures. To control the Schottky barrier height between ZnO and metals, a comprehension of crystal structures of Schottky metal layer is important.By the combination of ion beam deposition and combinatorial system, the Schottky barrier heights of binary alloys have been systematically controlled in response to the compositional fraction of Pt-Ru and Pt-W binary alloys. By using the combinatorial composition spread technique, it is proved that we could control Schottky barrier heights on ZnO. Pt is a candidate for high work function value metal. Ru and W are candidates for thermally stable metal with lower work function. Mixing of two metals is expected to realize the thermally stable but efficient UV detector with high Schottky barrier heights. Pt-Ru alloy metal film grew on ZnO substrates epitaxialy, and crystal structures change from Pt-phase (cubic structure) to Ru-phase (hexagonal structure) in the Pt-Ru alloy phase diagram. It was obtained that the Schottky barrier heights increased with increasing Pt content by current-voltage measurements. On the other hand, Pt-W alloy metal film showed amorphous phase and ohmic contact at a Pt content below 40 at.%. C-V measurement revealed an existence of an intermixing layer between Pt-W and ZnO.By employing the combinatorial composition spread technique, we can control Schottky barrier heights of a metal alloy on ZnO and investigate electric properties systematically. Polarization effects of ZnO will be discussed in detail in the presentation.
9:00 PM - A6.11
Anti-adhesive Behavior of a Biomedical Titanium Alloy After Ultraviolet Light Treatment.
Amparo Gallardo-Moreno 1 , Miguel A. Pacha-Olivenza 1 , M. Luisa Gonzalez-Martin 1 , Antonio Mendez-Vilas 1 , Jose Morales-Bruque 1 Show Abstract
1 Applied Physics, University of Extremadura, Badajoz Spain
It has been reported that ultraviolet illumination turns the originally surface of hydrophobic titanium dioxide films to hydrophilic surface. This effect, however, is time-dependent and the surface reconverts to hydrophobic when time passes (Zhang et al., 2005).In this work we have completely characterized the surface of a titanium alloy, after ultraviolet light treatment, through macroscopic physico-chemical techniques and microscopically by using an atomic force microscope. The effect of such changes is evaluated as a function of the irradiation time and the recovery time.In order to check the behavior of such an irradiated surface against bacterial adhesion we have studied the progress of a specific adhesion process in a parallel plate flow chamber and the results indicate that bacterial adhesion is reduced after ultraviolet illumination.Combination of the physico-chemical characterization with initial adhesion rates gives light to the factors mediating initial bacterial adhesion.P. Zhang, B.K. Tay, Y.B. Zhang, S.P. Lau, K.P. Yung. The reversible wettability of Ti containing amorphous carbon films by UV irradiation. Surf. Coat. Technol 198: 184-188 (2005).
9:00 PM - A6.12
Estimation of Thermal Shock Resistance for Microscopic Samples.
Andreas Zerr 1 Show Abstract
1 , LPMTM-CNRS, Universite Paris Nord, Villetaneuse France
An alternative method for experimental estimation or comparison of thermal shock resistances of ceramic compounds is suggested. This method could be of especial interest when the compounds are available only in microscopic amounts or when the attempts to fabricate dense polycrystalline bodies or single crystals of macroscopic sizes failed. This method could also be applied for compounds available only as thin films. The method is based on a combination of advantages of the high-pressure diamond anvil cell (DAC) technique and of nanoindentation testing. If the compound of interest exhibits Raman-active bands then examination of a microscopic sample on compression in a DAC using Raman spectroscopy allows determination of its Grüneisen parameter, γ. Here, the knowledge of the bulk modulus, B0, is required. The latter can be derived, for example, from compression measurements in a DAC using powder XRD and synchrotron radiation, if the crystal structure symmetry of the compound is known. It was shown in earlier experiments that this procedure provides satisfactory estimations of γ for minerals [e.g. A. Chopelas, Phys. Chem. Minerals, 17, 142 (1990)]. Further, it can be shown that for hard ceramic compounds the thermal shock resistance is nearly proportional to the ratio of hardness to Grüneisen parameter, H/γ. For microscopic samples the hardness H can be determined using nanoindentation measurements. In the present work the method was first tested for β-Si3N4 and then applied for comparison of thermal shock resistances of the recently discovered high-pressure nitrides of the group IVA elements having cubic spinel structure, γ-M3N4 (M=Si, Ge, Sn), and of the group IVB elements having cubic Th3P4-type structure, c-A3N4 (A=Zr or Hf).This work was partially supported by the Agence Nationale de la Recherche/France (grant NT05-3_42601); the Deutsche Forschungsgemeinschaft and the Adolf-Messer-Foundation/Germany.
9:00 PM - A6.13
A Calculation Method of the Deposition Profiles in Chemical Vapor Deposition Reactors Using Basis Functions.
Takahiro Takahashi 1 , Ken Kawamura 1 , Yoshinori Ema 1 Show Abstract
1 Department of Electrical and Electronic Engineering, Shizuoka University, Hamamatsu, Shizuoka, Japan
Fast and accurate calculation of the predicted results of Chemical Vapor Depositions (CVD) is very helpful to both the high-throughput optimization and making calculated combinatorial library of the CVD processes. In addition, robustness of the calculation process is important for automation of such calculation processes.Therefore, we developed a novel calculation method, by which robust and accurate calculations along with reduced computing cost were achieved, to reproduce deposition profiles in various CVD reactors.We found that a lot of reactors have their own “basis functions”, of which the concentration profiles of the species are mathematically composed. For a example, the batch type reactor with round shape substrates had the basis functions consisted of the modified Bessel functions of the first kind and zero-th order. The number of the basis functions equaled to the number of the species in the reaction mechanisms and was independent of the experimental conditions.Therefore, we changed the boundary value problems for estimating the governing equations of the reactors such as diffusion-reaction equations by iterations of numerical integrations into the problems of finding the linear combinations consisted of a few basis functions. We optimized the coefficients of the linear combinations by Genetic Algorithms (GA) and the other optimizing algorithms.We demonstrated the validity of the proposed method using various examples of the reaction mechanisms and conditions. The calculation method was free from the difficulties of the stiffness of the differential equations, because the governing equations were not estimated using numerical differential and integral calculus.Therefore, either replacing the conventional simulators with the proposed ones or combining both will improve the quality of the calculation processes.
9:00 PM - A6.14
Basic Research on Combinatorial Evaluation Method for Coefficient of Thermal Expansion.
Yuko Aono 1 , Seiichi Hata 2 , Junpei Sakurai 3 , Ryusuke Yamauchi 1 , Hiroyuki Tachikawa 3 , Akira Shimokohbe 3 Show Abstract
1 Mechano-Micro Engineering, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 2 Frontier Collaborative Research Center, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 3 Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
In this research, we introduce a method to evaluate coefficient of thermal expansion (CTE) on a thin film library deposited many deferent composition samples. CTE depends on composition of the material. There are many microelectromechanical system (MEMS) actuators using thermal behavior, but dependence of CTE on composition hasn’t been investigated systematically enough. Thus, applying the evaluation of CTE of various composition samples to combinatorial method is meaningful. A micrometer-scale bi-layer cantilever is employed for realization of the combinatorial evaluation method of CTE. The bi-layer cantilevers are suitable structure for integration on the thin film library and are composed by a sample thin film with unknown CTE and Young’s modulus as upper layer, and a base material with known those properties as lower layer. The thermal behavior of bi-layer cantilever, which is described as a function of CTE and Young’s modulus, is studied experimentally. The bi-layer cantilever bends due to difference of thermal expansion between both layers with heating. Projected length, which changes with the bending of the cantilever, is measured. CTE of upper layer is calculated from the projected length. But two values, CTE and Young’s modulus of upper layer, are unknown. So, in this research, a couple of bi-layer cantilevers with distinct base materials are used and solving simultaneous equations for the thermal behavior of the bi-layer cantilever gives the CTE without Young’s modulus of upper layer. The bi-layer cantilever (500 μm length, 1 μm thick Pd77Cu6Si16 at.% as upper layer, 1 μm thick SiN as lower layer) is fabricated. The projected length of the cantilever is measured with heating temperature width 150 K and this result is compared with theoretical one. The maximum error of projected length against theoretical one is 1.83 %. These results show that the equation can describe the thermal behavior well. Projected length is measured using a CCD camera that is set over the bi-layer cantilever. Using this method, it’s possible to realize high throughput evaluation of all cantilevers on a library. Resolution of the CCD camera causes the measurement error. The error of CTE calculated by the simultaneous equations is analyzed, providing the resolution of CCD camera is 2 μm, two cantilevers with 500 μm length, 1 μm thick Pd77Cu6Si16 at.% as upper layer and distinct lower layers, 1 μm thick SiN and 1 μm thick SiO2, and heating temperature width 100 K. The targeted properties range of sample thin film are 10~30x10-6 /K in CTE and 50~200 GPa in Young’s modulus respectively and the error of CTE is analyzed in this range. The maximum error of CTE is 0.79x10-6 /K, when CTE is 10x10-6 /K and Young’s modulus is 200 GPa. In conclusion, CTE can be evaluated accuracy using proposal method. Further works are to survey another base material more sensitive and then fabricate the bi-layer cantilevers on thin film library.
9:00 PM - A6.2
Advanced Energy-loss Models for Elemental Depth Profiling of Amorphous or Polycrystalline Targets using Ion Scattering.
Rafael Pezzi 1 2 , Matt Copel 1 , Pedro Grande 2 , Israel Baumvol 2 Show Abstract
1 , IBM T.J. Watson Research, Yorktown Heights, New York, United States, 2 , Instituto de Física - UFRGS, Porto Alegre - RS, RS, Brazil
Quantitative, elemental high depth resolution profiling in near-surface regions of solids is a cumbersome or even an impractical task using medium energy ion scattering (MEIS) since the energy-loss probabilities in these regions are reportedly asymmetric, i.e. it deviates from the commonly used Gaussian approximation. Whereas this asymmetry can be attributed to inelastic energy transfers during single atomic encounters, no practical and systematic solution to this issue has been given so far. Ab-initio calculations based on solutions of the time-dependent Schrödinger equation indicates that proper evaluation of asymmetric energy transfers involves two modifications in standard ion energy-loss models, namely, i) the substitution of the usual Gaussian approximation by an asymmetric distribution function that reproduces the average energy-loss and spectral-broadening quantified by the stopping power energy straggling constants, respectively and ii) the evaluation of an additional energy-loss parameter that appears in addition to the usual stopping power and energy straggling constants. i) requires the evaluation of advanced solutions of the Bothe-Landau equation while ii) requires the evaluation of an additional effect commonly overlooked in ion scattering experiments, namely the energy loss due to the excitation and/or ionization of the target atom during the near-central collision that results in backscattering. It is shown that this additional effect can be properly quantified by the additional broadening observed in the energy spectrum. Such broadening depends on details of the interaction between the projectile and the electronic structure of the target-atom and can be estimated by simple models.Finally, we present analytical approximations for both, the replacement of the usual Gaussian approximation by an asymmetric line-shape and for the evaluation of the additional broadening caused by the near-central collision as well. This novel approach is corroborated by comparison with MEIS spectra corresponding to 100 and 200 keV H+ ions incident in 0.2 to 3.0 nm-thick TiO2 and HfO2 films on Si.
9:00 PM - A6.3
A Combinatorial Approach to the Study of the Phase Diagram and Thermoelectric Properties in the Ce-Co-Sn System.
Evan Thomas 1 , Kao-Shuo Chang 1 , Makoto Otani 1 , Nathan Lowhorn 1 , Winnie Wong-Ng 1 , Peter Schenck 1 , Martin Green 1 Show Abstract
1 Ceramics Division, Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
High-throughput combinatorial mapping is a state-of-the-art screening technique for accelerating the selection and introduction of thermoelectric materials into the manufacturing process. A Ce-Co-Sn composition spread has been synthesized by combinatorial methods using the sputtering technique – where precursors are deposited successively through physical masks to vary the elemental compositions – and the phase diagram characterized by X-ray diffraction. The phase relationships in the vicinity of the known Ce3Co4Sn13 phase with an open cage-like structure are of particular interest due to the relationship between the rattling motion of guest atoms and the phonon thermal conductivity. The Seebeck coefficients and electrical conductivity (power factor = α2σ) of each composition of the high-quality fabricated film are measured using a rapid screening system developed at NIST. The data for the compositions with the most promising thermoelectric behavior are compared to data obtained from measurements of bulk samples. This technique may rapidly advance the exploration of thermoelectric intermetallics in comparison to conventional trial-and-error synthetic methods.
9:00 PM - A6.4
Relationship Between Thermal and Mechanical Properties of Biocomposites and Crystallinity of Treated Natural Fiber.
Seong Ok Han 1 , Young Hee Han 1 , Hye Young Choi 1 Show Abstract
1 , Korea Institute of Energy Research, Daejeon Korea (the Republic of)
As an environmentally friendly material biocomposite made of natural fiber reinforcement and polymer matrix has been studying actively worldwide. The main application of biocomposite is for automobile industry due to its lightweight and comparable mechanical properties to glass fiber reinforced polymer composites. Researches for enhancement of the mechanical properties and solution for some drawbacks of biocomposite such as dimensional stability are ongoing. The natural fiber reinforced polypropylene(PP) or unsaturated polyester(UP) biocomposites were fabricated and characterized in terms of reinforcing effects of natural fibers on thermoplastic or thermosetting polymer. Kenaf(KE) or henequen(HQ) fibers were treated with electron beam irradiation(EBI) of 200kGy dose or 5wt% NaOH solution. The 4-types of biocomposites(KE/PP, HQ/PP, KE/UP, HQ/UP) were fabricated and characterized by dynamic mechanical analysis, thermal gravimetric analysis, scanning electron microscopy. The kenaf fiber showed the higher reinforcing effect on both PP and UP biocomposites than henequen fiber. The highest storage modulus of biocomposite was obtained with the combination of UP and 5wt% NaOH treated kenaf fiber. Also, we have studied thermomechanical properties such as coefficient of thermal expansion(CTE) of biocomposite in order to investigate the reinforcement effect on dimensional stability of biocomposite. Besides, we irradiated henequen fiber with electron beam of different dose (0~500 kGy) to remove impurities and grant the functional groups on the fiber surface resulting in improving adhesion between reinforcement and polymer matrix. The EBI treatment of henequen fiber shows the enhanced mechanical performance of biocomposite such as dynamic mechanical property and interfacial adhesion providing the optimum dose of 10 kGy. The EBI surface treatment effect of henequen fiber with different dose shows a good agreement with thermomechanical, dynamic mechanical and interfacial properties of biocomposites. These results are closely related to the crystallinity of cellulose and the FT-IR. DSC and XRD were applied to examine crystalline properties of cellulose.
9:00 PM - A6.5
An Autonomous Mobile-Agent System to Model The Calculation Process of Film Depositions.
Takahiro Takahashi 1 , Noriyuki Fukui 1 , Masamoto Arakawa 2 , Kimito Funatsu 2 , Yoshinori Ema 1 Show Abstract
1 Department of Electrical and Electronic Engineering, Shizuoka University, Hamamatsu, Shizuoka, Japan, 2 Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo Japan
Process simulators to reproduce the experimental results of the deposited films are very helpful for developing Chemical Vapor Deposition (CVD) processes and the other film deposition processes. However, the huge time and expense needed for calculations (calculation costs) of the simulators limit their applications to making calculated large combinatorial library of the deposited films and high-throughput optimization of the CVD processes. One effective way to decrease the calculation costs is to model the calculation processes of the simulators, that is, by creating mathematical models of the correlation between calculation conditions and calculated results of the simulators and replacing the simulators with the models. However, it is very difficult for researchers to make appropriate models, because modeling includes a lot of difficult procedures, such as making high-quality training data and operating advanced modeling software. Therefore, we developed an autonomous modeling system for the calculation processes of the simulators using mobile-agent technology and investigated the quality of the models proposed by the system. A mobile agent is autonomous software, which moves in computer-networked environments and operates software resources in server computers. The system consists of one mobile agent and three platforms for the agent, where user interface, the process simulator and generalized modeling software for humans are installed, in the server computers. The agent autonomously moved in the computer-networks, and operated the process simulator in order to make training data needed for modeling and then operated the generalized modeling software using the training data and finally the agent created the models. The models, which created by the agent, showed good reproducibility and predictability for the film properties such as the stepcoverage representing the film uniformity and the filling ratio of the films in the trench of the substrate. Thus, the model made by the system can be a predictor of the calculated results of the process simulator of CVD.
9:00 PM - A6.6
Analysis of Thresholding Algorithms Using Atomic Force Microscopy Images.
Thomas Sadowski 1 2 , Paida Munhutu 1 2 , John Daponte 2 , Elena Garcia 2 , Christine Caragianis-Broadbridge 2 , Monica Sawicki 2 , Chantrie Hayden 2 , Leah Mirabelle 2 , Patrick Benjamin 2 Show Abstract
1 Physics, Southern Connecticut State University, New Haven, Connecticut, United States, 2 Computer Science, Southern Connecticut State University, New Haven, Connecticut, United States
Recently, computer assisted particle analysis has played an important role in characterizing nanoparticles. Since this type of analysis requires an accurate binary representation of a gray scale image, choosing the proper thresholding algorithm for the imaging modality under investigation is essential. In a previous study, the performance of the Entropy, Kittler-Illingworth, Maximum Likelihood, Riddler-Calvard, Otsu and Tsai  thresholding algorithms were evaluated. More recently, these algorithms were applied to Atomic Force Microscopy (AFM) images of antimony nanoparticles of an unknown size and distribution. This study compared the diameter and area of the particles in a binary image to those in the corresponding gray-scale image . It was determined that the Kittler-Illingworth and Entropy algorithms provided the most accurate results. The purpose of the current study was to identify which of these two algorithms yielded more accurate results when applied to a sample of known shape and morphology.NIH ImageJ , a free image processing software package, was used to implement both the thresholding algorithms and the particle analysis. The process involves converting a color AFM image obtained from a Digital Instruments (DI) Nanoscope IIIa Multimode Scanning Probe Microscope to an 8 bit gray scale image prior to applying the desired thresholding algorithm. Due to dust contamination, it was often necessary to apply a 5 by 5 median filter to the gray scale images prior to thresholding. Once the binary images were obtained, the particle analysis was used to generate estimates of each particles length and width. These results were then compared to the known dimensions of a 5 micron by 5 micron pitch calibration standard.The results of this study identified Kittler-Illingworth as the algorithm that yields the most accurate results. Although most of the effect of the dust particles were removed, the entropy algorithm tended to accentuate any remaining noise resulting in several binary images that were found to be unacceptable as input for particle analysis. This research was supported by NSF Grant MRSEC DMR05-20495.Mehmet, Sezgin. “Survey over image thresholding techniques and quantitative performance evaluation.” Journal of Electronic Imaging. Vol. 13(1) Jan 2004: 146 – 165 DaPonte, J., Sadowski, T., Broadbridge, C. C., Day, D., Lehman, A., Krishna, D., Marinella, L., Munhutu, P., and Sawicki, M. “Comparison of thresholding techniques on nanoparticle images” Visual Information Processing XVI. 6575, 65750L (2007). http://rsb.info.nih.gov/ij/docs/
9:00 PM - A6.7
Consistency and Accuracy of Computer Assisted TEM Image Analysis.
Thomas Sadowski 1 2 , John Daponte 2 , Christine Caragianis-Broadbridge 1 , Paida Munhutu 1 2 , Ann Lehman 1 3 , Elena Garcia 2 , Monica Sawicki 1 , Chantrie Heyden 1 , Leah Mirabelle 1 , Patrick Benjamin 1 Show Abstract
1 Physics, Southern Connecticut State University, New Haven, Connecticut, United States, 2 Computer Science, Southern Connecticut State University, New Haven, Connecticut, United States, 3 Facility for Electron Microscopy, Trinity College, Hartford, Connecticut, United States
Nanoparticle analysis in Transmission Electron Microscopy (TEM) continues to grow in importance as technological advancements become increasingly dependent on nanotechnology . Since nanoparticle properties such as size (diameter) and size distribution are often important in determining potential applications, a particle analysis is often performed on TEM images. Traditionally done manually, this has the potential to be labor intensive, time consuming, and subjective. To resolve these issues, automated particle analysis routines are becoming more widely accepted within the community. When using such programs, it is important to account for the differences among them due to variations in the respective algorithm, which must be tested prior to application on a large data set. The purpose of this study was the comparison of the automated particle analysis routines found in ImageJ  and Gatan Digital Micrograph  by applying them to gray-scale TEM images of nanoparticles with a known size as an alternative to manual counting techniques. These approaches still have their drawbacks, as difficulties arise when populations of particles include aggregates. In these cases ImageJ was used to break the agglomerations into individual particles by means of a watershed algorithm . The results obtained from this study revealed some advantages and disadvantages of both algorithms and provided insight into potential errors associated with computer-assisted techniques.This research was supported by NSF Grant MRSEC DMR05-20495. Mark L. Schattenburg, “The Importance of Nanotechnology and Nanometrologyfor Space Instrumentation”, Massachusetts Institute of Technology, Space Nanotechnology Laboratory Center for Space Research, 2001 http://rsb.info.nih.gov/ij/index.html http://www.gatan.com/imaging/ http://bigwww.epfl.ch/sage/soft/watershed/
9:00 PM - A6.8
Combinatorial Searching for Pt-Zr-Ni Thin Film Amorphous Alloys for Glass Lens Mold.
Mitsuhiro Abe 1 , Seiichi Hata 2 , Ryusuke Yamauchi 1 , Junpei Sakurai 3 , Akira Shimokohbe 3 Show Abstract
1 Mechano-micro engineering, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 2 Frontier Collaborative Research Center, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan, 3 Precision and Intelligence Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
Recently, the materials of functional optical glass lens mold have been studied. We had searched for the novel amorphous alloy having high crystallization temperature Tx using combinatorial arc plasma deposition (CAPD). In the previous work, Ru-based and Pt-based alloys were investigated. Although these amorphous alloys had high Tx of more than 973 K, they did not show good machinability. In this work, in order to progress machinability of amorphous samples, the various properties of the Pt-Zr-Ni thin film amorphous alloys were investigated. The properties of desired sample were as follows: (1) Tx exceeds 923K. (2) σf exceeds 2.0GPa. (3) Non-sticking characteristics with melting glass. (4) Good machinability.As the process of searching for amorphous alloys, 3267 samples were deposited by CAPD. The phase and composition of the CAPD samples with thickness more than 500nm were evaluated. Thickness of the CAPD samples was measured by a white-light interferometer. Compositions were measured by an energy dispersive X-ray fluorescence spectrometer. Phases were identified by an X-ray diffractmeter. From these results, 312 amorphous compositions were found. The period of searching for amorphous composition was only about twenty days. This shows the effectiveness of CAPD. Tx and fracture stress σf of the sputter-deposited amorphous samples having the same composition as amorphous CAPD samples were measured because CAPD samples were too small to evaluate thermal and mechanical properties. Tx was measured by differential scanning calorimeter. σf was measured by tensile tests using a thermo-mechanical analyzer.At first, in order to investigate the effect of Pt-content on Tx, the PtxZr (90-x)Ni10 samples were fabricated by the sputter. Pt-content was ranged from 20 to 50 at.%. Tx increased with increasing Pt-content, and the Pt51Zr39Ni10 sample showed the highest Tx of 939K. The sample has needs to show Pt-rich composition to show Tx of more than 923K. However, sf of all sample showed less than 2GPa.Subsequently, in order to search for Pt-rich sample having high sf, the properties of the Pt50Zr(50-x)Nix sample were investigated. Ni-content was ranged from 5 to 15 at.%. As the results, Tx increasing with increasing Ni-content. The Pt50Zr36Ni14 sample showed the highest Tx of 985 K and σf of 2.12 GPa.Sticking characteristics of the Pt50Zr36Ni14 sample with melting glass were measured. Melting glass was felled in drops on the samples, and then droplet was removed without adhering to the sample.Machinability of the Pt50Zr36Ni14 sample was evaluated by cutting tests using diamond tools. Surface roughness of this sample worked was several nanometers. This result indicated that the Pt50Zr36Ni14 sample showed good machinability. From these results, it is considered that the Pt50Zr36Ni14 sample is suitable for the materials for glass lens mold.
9:00 PM - A6.9
Preparation of Blue-emitting Phosphorescent Iridium(III) Complex under Ultrasound Reaction.
Hong Jeong Yu 1 , Kwanhwi Park 1 , Sung Hyun Kim 1 Show Abstract
1 Dept. of Chemical and Biological Engineering, Korea University, Seoul Korea (the Republic of)
Ir(pmb)3 (Iridium(III) Tri(1-phenyl-3-methylbenzimidazolin-2-ylidene-C,C2’) was synthesized for the development of blue-emitting Ir(III) complex. The Ir(C^C:)3 complexes should have high energy ligand field states because the bond length differences suggest that the cyclometalated carbenes are stronger field ligands than their pyrazolyl or pyridyl counterparts. For the synthesis of Ir(pmb)3, the reaction is occurred through two steps. The first step is the synthesis of Ir-dimer ([(pmb)2IrCl]2) with IrCl3.H2O and [pmb]I-, and the second step is the synthesis of Ir(pmb)3 with Ir-dimer and [pmb]I-. The reaction yield of Ir-dimer is known ad very low (12.7%). However ultrasound chemical reactions have carried out high yields and short reaction times in many different types of organic reactions compared with conventional methods. The yield of Ir-dimer was increased by increasing the intensity of ultrasound. The maximum yield of Ir-dimer was 52.8 % at 450 W/m2 of ultrasound intensity. Ir(pmb)3 as the final product could be synthesized only in one step when the ultrasound intensity was over 500W/m2 of ultrasound intensity. The yield of Ir(pmb)3 was 31.23 % at 500 W/m2 of ultrasound intensity. The reaction yield was increased by 20% and two step reaction was shorten to one step reaction through ultrasound treatment.
David S. Ginley National Renewable Energy Laboratory
Michael J. Fasolka National Institute of Standards and Technology
Alfred Ludwig caesar, Bonn; Ruhr-Universitaet Bochum
Mikk Lippmaa Institute for Solid State Physics
A7: Combinatorial Structural Analysis/Mechanical Properties
Friday AM, November 30, 2007
Independence E (Sheraton)
9:00 AM - **A7.1
Assessing the Accuracy of Polymer High-Throughput Mechanical Property Screening.
J. Carson Meredith 1 , Pedro Zapata 1 Show Abstract
1 Chemical Engineering, Georgia Tech, Atlanta, Georgia, United States
This talk will present an overview of current approaches to the high-throughput screening of polymer mechanical properties. These methods are becoming increasingly important industrially, due to the time and expense involved in conventional mechanical property screening. On the other hand, there also remains some reluctance to accept high-throughput mechanical screening (HTMS) as a valid characterization method. This is not without reason: mechanical properties are often dependent on the sample size and geometry of the test instrumentation. HTMS generally involves reductions in sample size and deformation geometries. In fact, a number of recent HTMS approaches involve an indenter that makes direct contact with a polymer film sample. We present detailed results for screening a large variety of thermoplastic polymers using a modified dart-type mechanical test (HTMECH). The results of high-throughput screening are compared carefully to conventional mechanical screening measurements, e.g., ASTM methods. We find that good agreement between conventional and HTMECH in trends of modulus and tensile strength occurs for most thermoplastics considered. However, low-yielding polymers tend to show disagreement. We discuss the use of a yield-strength criterion for the design of high-throughput mechanical screening involving direct contact of an indenter with the sample. Designing the geometry to avoid yielding appears to be a solution for increasing the range of materials accessible by HTMS.
9:30 AM - **A7.2
Improving the Reliability of Nanoindentation Results from Combinatorial Polymer Libraries.
Oden Warren 1 , Wei Che 1 , Michael Fasolka 2 , Christopher Stafford 2 Show Abstract
1 , Hysitron, Inc., Minneapolis, Minnesota, United States, 2 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Combinatorial libraries are often in thin-film form, and thus nanoindentation is becoming increasingly incorporated into combinatorial workflows as means for mechanical property screening. However, combinatorial polymer libraries present a significant challenge to screening by nanoindentation in large part because of their viscoelasticity. This time-dependent aspect of polymer deformation is detrimental to the accuracy of nanoindentation results; consequently, considerable research effort has been expended in recent years to identify an optimum test protocol, or to account for viscoelasticity through modeling, but a reliable solution remains to be found. We have undertaken a combinatorial approach to better understand the problem at hand. Specifically, we have conducted a multi-parameter nanoindentation study of thickness-gradient polystyrene libraries having narrow molecular weight distribution with the goal of systematically investigating film thickness, deformation rate, peak-interaction hold time, tip geometry, and control mode effects on the determined elastic modulus and hardness. It became evident early in the study that the usual method of performing nanoindentation in a manner that makes polymer force-displacement curves more amenable to standard unloading analysis is not robust, and that an alternative test protocol is preferable because it altogether eliminates any possibility of the dreaded creep-induced, forward-going nose. Very reproducible elastic modulus and hardness values were obtained over a wide range of deformation rates and peak-interaction hold times when using the alternative test protocol. This presentation will focus on that particular aspect of a wider combinatorial study, and will provide a sensible mechanistic explanation for our observations. Of course the alternative test protocol is applicable to nanoindentation of polymers in general, and not only to combinatorial polymer libraries.
10:00 AM - **A7.3
Advances in Surface Wrinkling as a Metrology.
Jun Young Chung 1 , Thomas Chastek 1 , Michael Fasolka 1 , Christopher Stafford 1 Show Abstract
1 Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
We present an efficient and robust strategy that harnesses wrinkling instabilities for combinatorial measurements of thin film material properties. Specifically, we use a novel design that employs observations of a thin film suspended over a circular hole cut into an elastic substrate. Upon compression, two distinct regions – film/substrate (outside the hole) and free-standing film (above the hole) – wrinkle independently with different characteristic wavelengths. This geometry further yields a distribution in strain (or stress) around the perimeter of the hole, which can be used to directly determine the critical strain of wrinkling initiation. We demonstrate that, based on the well-established wrinkling mechanics, these measured wavelengths and critical strain can render the modulus, thickness, and Poisson’s ratio of thin films simultaneously. In addition, we describe the capability of this new strategy for quantifying residual stresses in thin films that arise as a natural consequence of film formation, such as spin coating, dip coating, and flow coating.
10:30 AM - A7.4
High Throughput Stress Measurements by Micro-Raman Spectroscopy in Polycrystalline Silicon Thin Film Solar Cells on Glass.
George Sarau 1 , Michael Becker 1 2 , Andreas Berger 1 2 , Jens Schneider 3 , Silke Christiansen 1 2 4 Show Abstract
1 , Max Planck Institute of Microstructure Physics, Weinberg 2, Halle/Saale, Sachsen-Anhalt, Germany, 2 , Martin-Luther-University Halle-Wittenberg, Hoher Weg 8, Halle/Saale, Sachsen-Anhalt, Germany, 3 , CSG Solar AG, Sonnenallee 1-5, Thalheim Germany, 4 , Institute of Photonic Technology, Albert-Einstein str. 9, Jena Germany
In the present work micro-Raman spectroscopy (µRS) and Atomic Force Microscopy (AFM) were used to correlate mechanical stress distribution with topography in 1.5 µm polycrystalline silicon thin film solar cells deposited onto glass. µRS is a non-destructive method, with a high throughput potential to quantify stress distributions on large areas.Stresses occur due to thermal mismatch between glass and the silicon layer during solid phase crystallization at elevated temperatures for several hours, especially once the silicon layer crystallizes over glass beads (~1µm in diameter). These beads are statistically and unevenly distributed over the glass substrate for light trapping purposes. Stresses degrade solar cell performance once they result in crack formation in the silicon layer.The µRS and AFM measurements show that there is an average compressive stress of 68±25 MPa caused by the pronounced bending of the Si film at the surface in areas of uniform bead coverage. In regions without beads an average tensile stress of -45±25 MPa is measured. High compressive stresses up to 800±25 MPa were observed in areas where beads cluster in rows surrounded by areas without beads. Areas with the highest stresses are also prone to the formation of high densities of extended defects such as dislocations, twin lamellae and low angle grain boundaries, which need to be kept at a minimum.Materials optimization is carried out based on stress quantification with the intention to reduce stresses and densities of extended defects in the silicon layer.
10:45 AM - A7.5
High-Throughput Combinatorial Study of Local Stress in Thin Film Composition Spreads.
Noble Woo 1 , Bryan Ng 2 , R. van Dover 3 Show Abstract
1 Chemistry and Chemical Biology, Cornell University, Ithaca, New York, United States, 2 Materials Science and Engineering, M I T, Cambridge, Massachusetts, United States, 3 Materials Science and Engineering, Cornell University, Ithaca, New York, United States
We have developed an approach to investigate stress in thin films with sub-mm lateral spatial resolution using a dense array of pre-fabricated cantilever beams prepared by MEMS techniques. Stress-induced deflection of the cantilever is interrogated by an optical (laser/position sensitive detector) measurement system. Composition spread films are deposited on the cantilever array using a three-gun on-axis magnetron co-sputtering system. The position-dependent composition is inferred using rate calibrations and verified by electron microprobe/energy dispersive spectroscopy. We demonstrate the function of this system using a Fe-Ni-Al composition spread, and display the as-deposited stress in these films with ~1 at.% resolution. The system has a sensitivity and resolution that allows measurement of, e.g., magnetostrictively-induced strains as small as 0.1 ppm. This approach will also enable measurement of the composition dependence of other electromechanical properties such as the martensitic phase transition temperature of traditional and ferromagnetic shape-memory alloys, as well as the properties of hydrogen storage materials and the magnetic response of magnetostrictive materials.
11:00 AM - A7.6
High-throughput Detection of Magnetostriction in Thin-film Composition-spread Cantilever Unimorphs.
Jason Hattrick-Simpers 1 , Dwight Hunter 1 , Kyu Sung Jang 1 , James Cullen 1 , Samuel Lofland 2 , Leonid Bendersky 3 , Manfred Wuttig 1 , Ichiro Takeuchi 1 Show Abstract
1 Materials Science and Engineering, University of Maryland, College Park, Maryland, United States, 2 Department of Physics and Astronomy, Rowan University, Glassboro, New Jersey, United States, 3 Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Magnetostriction is the ability of a material to change shape under the application of an applied magnetic field. This is an important materials property with applications in such fields as sensors and actuators. To date a quantitative method for measuring magnetostriction in a high-throughput manner has not been successfully implemented. Here a method for measuring magnetostriction on thin-film cantilever unimorph composition-spreads will be presented. An optical technique is used to monitor the deflection of the cantilever unimorphs as a function of applied magnetic field. The deflection of the cantilevers can then be converted quantitatively into a value of the magnetostriction through a simple model. As an example system results will be presented on binary Fe-Ga and ternary Fe-Ga-Pd and Fe-Ga-Al. The stabilization of non-equilibrium phases in the as-deposited samples as well as their effect on magnetostriction will be discussed.
A8: High Throughput Optimization of Metals and Alloys
Friday PM, November 30, 2007
Independence E (Sheraton)
11:30 AM - **A8.1
Combinatorial Investigation of Ternary and Quaternary Shape Memory Thin Films and Microactuators with Improved High-Temperature Properties and Small Thermal Hysteresis.
Robert Zarnetta 1 2 , Sigurd Thienhaus 1 2 , Alan Savan 1 , Alfred Ludwig 1 2 Show Abstract
1 Combinatorial Materials Science Group, caesar, Bonn Germany, 2 Institute of Materials, Ruhr-University Bochum, Bochum Germany
Several actuator materials are known for their applicability as microactuators. Among them, TiNi-based thin films show the largest available actuation forces and displacements. However improved materials properties with respect to higher transformation temperatures and smaller thermal hysteresis are required in order to facilitate new applications, allow better actuator control and improve the long-term stability.In this work, combinatorial methods were applied towards the fabrication and characterization of shape memory thin film materials libraries. Advanced sputter deposition methods were used to create complete ternary Ti-Ni-X (X = Cu, Pd, Ag, Pt, Zr, Hf) libraries, or sections thereof, on thermally oxidized 4” Si (Si/SiO2) wafer substrates. The material libraries were fabricated from wedge-type multilayer thin films sputtered from elemental targets and subsequent in situ annealing for 1 hour. Automated temperature-dependent resistance measurements (R(T)), energy dispersive X-ray analysis (EDX) and X-ray diffraction measurements (XRD) have been applied for the high-throughput characterization of the composition spreads. Focused ion beam (FIB) techniques were used for transmission electron microscopy (TEM) sample preparation and later for the investigation of thin film microstructures.Within the Ti-Ni-Cu, Ti-Ni-Ag and Ti-Ni-Pd systems, the composition regions where reversible phase transformations occur in the temperature range of -40 °C to 250°C were investigated. The corresponding transformation temperatures were determined and the observed transformation characteristics could be related to the structural and compositional information. For Ti-Ni-Cu, results for various annealing temperatures, i.e. 500 °C, 600 °C and 700 °C and a Si/SiO2/Si3N4 substrate are compared. The application of the observed R-phase transformations, with their characteristically low thermal hysteresis, for high-speed thin film microactuators will be discussed. For the characterization of the actuator properties, selected quasi-binary composition gradients e.g. Ti50Ni50-xCux (0 < x < 50 at%) were deposited onto 100 µm thick micro-machined Si cantilever arrays. Transformation and actuation characteristics were investigated over cycles in a temperature range of -100 °C to 600 °C. Preliminary results with Ti-Ni-Hf, Ti-Ni-Zr and Ti-Ni-Pt high-temperature shape memory alloys and further work on quaternary Ti-Ni-Cu-Pd thin films with a theoretically predicted zero thermal hysteresis, will be discussed.
12:00 PM - A8.2
Micro-hotplates as Processing and Characterization Platforms for Functional Fe-based Thin Film Systems.
Sigurd Thienhaus 1 2 , Sven Hamann 1 2 , Michael Ehmann 1 , Robert Hiergeist 1 , Alan Savan 1 , Alfred Ludwig 1 2 Show Abstract
1 Combinatorial Materials Science Group, caesar, Bonn Germany, 2 Institute for Materials, Ruhr-University Bochum, Bochum Germany
Micro-hotplate arrays on 4” Si-wafers were fabricated in order to be used as high-throughput material processing and characterization platforms for thin films. A micro-hotplate (MHP) consists of a SiO2/Si3N4 membrane (1µm) supported by a Si frame, with embedded Pt heater and measurement electrodes. It is shown that micro-hotplates have unique properties for the controlled annealing of thin film materials (up to 1000°C), as temperature and temperature change can be precisely controlled by in situ measurements. The heating and cooling rates can be extremely high (up to 10^4 K/s), due to the low thermal mass of the MHP heater. Therefore MHPs can be used for quenching high-temperature phases, i.e. fabricating metastable phases with functional properties. As a first example, Fe70Pd30 films have been processed. After annealing and rapid cooling, this ferromagnetic shape memory alloy forms a metastable phase which shows a characteristic thermoelastic martensitic transformation. A further example is the controlled fabrication of nanoscale multiphase thin films. Fe-Pt multilayers were annealed to obtain a nanocrystalline structure which is essential to obtain the “exchange spring” effect for which this system is a potential candidate. Using the additional measurement electrodes, in situ temperature-dependent resistance measurements were carried out in parallel with annealing. This enables detection of microstructural changes in the films, such as phase transformations. Furthermore MHP arrays can be used as active substrates during deposition of uniform films, or for efficient high-throughput heat treatments of composition spread thin films.
12:15 PM - A8.3
Combinatorial Study About Size Effects in Phase Formation and Crystal Orientation of the Ti-Ni-Cu System.
Cesare Borgia 1 , Ralph Spolenak 1 Show Abstract
1 Department of Materials, ETH Zurich, Zurich Switzerland
The ternary Ti-Ni-Cu system is the object of great interest in the field of Shape Memory Alloys (SMA) with small hysteresis and improved transformation reversibility and fatigue properties. Nearly equiatomic Ti-Ni alloys with small additions of Cu find application in a quite large number of fields ranging from biomedical devices to (N)MEMS actuators. The transformation behavior SMA is strongly related to the crystallographic structure and lattice mismatch between austenitic and martensitic phases. Despite the strong interest demonstrated by the research community about the shape memory properties of this system, only limited information is available about the related phase diagram and size effects in the nanometric scale. Amorphous thin films of different thicknesses were produced by magnetron co-sputtering of pure Ti, Ni and Cu targets at room temperature and successively crystallized at different annealing temperatures. The relationships between film thickness, crystallographic orientation and nanomechanical properties have been studied using SEM, XRD and nanoindentation. The phase mappings of the annealed thin films show a remarkable agreement with the ternary phase diagram of the bulk alloy. In addition, a correlation was evidenced between the phase composition and the mechanical properties. In particular, regions rich in the Ti2Ni intermetallic phase show a considerable increase in the values of hardness and elastic modulus.
12:30 PM - A8.4
Combinatorial Study of Nanoscale Ti-Ni-Zr by Parallel nano-Differential Scanning Calorimetry.
Patrick McCluskey 1 , Joost Vlassak 1 Show Abstract
1 School of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, United States
The parallel nano-differential scanning calorimeter (PnDSC) is a new combinatorial device for studying the thermal properties of complex nanoscale material systems. The PnDSC uses an array of micromachined calorimetric cells to discretize a continuous composition gradient into multiple samples of specific composition. In this way a library of samples can be created and measured simultaneously, greatly reducing the time for such an analysis when compared to a traditional one-at-a-time approach. Also very fast scan rates ranging 1-100 K/ms make for even shorter measurement times. Each calorimetric cell of the PnDSC can measure heat capacity with ~ 1 nJ/K short-term noise, and even greater sensitivity in differential mode. These sensitivities are far better than those reported for commercially available “ultra-high sensitivity” DSCs (~ 1000 nJ/K) and are required to measure thermal properties in nano-materials. Much of this improved sensitivity can be attributed to the significantly reduced addendum of the nano-calorimeter, which has a heat capacity of ~ 1000 nJ/K. Until recently such sensitive measurements were unobtainable, creating a dearth of materials data in the nanoscale range, where material properties are often a function of length scale and differ significantly from their bulk values. In the age of technology miniaturization, traditional mechanical-electrical approaches to device design fail. Functions that were once performed by device components are now required of materials. Thus, functional and active materials are assuming a more important role in research and technology. These materials are often multi-component and the characteristics of the function or activation typically depend on composition. Ti-Ni-Zr shape memory alloy (SMA) resides in this set of nano-multi-component materials and demonstrates the capabilities of the PnDSC. SMAs are prized because of their high power density as an actuation material. Ti-Ni-Zr, in particular, is useful because it is relatively low cost, shows ~ 90% shape memory effect recovery, and its transformation temperature can be tailored with Zr content. The Zr content can also influence other transformation properties such as enthalpy, transformation temperature range, and stability. All of these properties are important design characteristics when considering implementation of the material. Also, because of scaling effects, these materials properties should be measured at the appropriate implementation length scale. We will present a combinatorial calorimetric analysis of nanoscale Ti~50-XNi~50ZrX, creating a compositional map of these important properties and demonstrating the capability of the PnDSC. To the best knowledge of the authors, this is the first time these measurements have been performed at the appropriate length scale and in such an efficient combinatorial manner.