Wei Chen - US grants

[unreadable] DESCRIPTION (provided by applicant): The mammalian olfactory system has a tremendous capability to discriminate thousands of different odor molecules. Recent advances in molecular biology and functional imaging have established that odor information is encoded as spatial patterns of activated glomeruli distributed on the olfactory bulb surface. How these glomerular coding patterns are transformed within the olfactory bulb circuits is critical to odor discrimination and recognition, but remains to be understood. As a unique feature of olfactory bulb neuronal circuits, most of the cell-cell communication is mediated by synapses and gap junctions made between dendrites of principal mitral/tufted cell and local interneurons. Our previous research has established how signals encoding odor information are transmitted and regulated dynamically along the mitral cell primary and secondary dendrites. The aim of this renewal application is to continue this line of research by combining patch-clamp recording, two-photon calcium imaging and green fluorescence protein-targeted transgenic/knock-in mice to analyze how the bulbar neurons interact with each other at a level of circuits to process glomerulus-specific odor information. Specifically, we will test three major hypotheses. First, one important function ofperiglomerular cells is to orchestrate the glomerulus-specific firing synchrony through both dendritic synaptic transmission and electrical coupling in the glomerulus. Second, neuronal activities within different glomeruli can also achieve temporary synchrony, and both periglomerular and granule cells play a important role. Third, signal transmission in granule cell dendrites and spines has a spatio-temporal dynamics that can mediate the coupling and uncoupling of mitral cells from different glomeruli as in response to different odorants. These experiments are in line with our long-term objective to obtain critical information on the functional principles of olfactory bulb dendritic circuits and how these principles are involved in odor signal processing and discrimination. The progress toward this objective will yield novel insights into how the olfactory system can recognize thousands of different odors, and into the neural basis of smell-related disorders. [unreadable] [unreadable]

The funds requested in this proposal will support the PI's efforts in uniting productive research and excellence in teaching in the Chemistry Department at Mount Holyoke College. Over the next three years, a research program that involves the independent and simultaneous tailoring of surface topography and chemical structure for controlled wettability will be established and several teaching initiatives that aim to promote polymer chemistry at the undergraduate level will be implemented.

The objectives of the proposed research are to nationally control wettability of surfaces by manipulating surface topography and surface chemical structure and to provide a fundamental understanding of the basis of wettability. The research involves: (1) the adsorption of charged polystyrene latex particles to oppositely charged poly(ethylene terephthalate) surfaces to form surfaces with different topographies/roughness, (2) the introduction of discrete functional groups to first smooth and then rough surfaces through organic transformations. The two research stages combine to form a method for preparing robust stable surfaces of variable wettability. The combination of surface topography and density, location and identity of surface-chemical functionality should, in principle, control wettability. Holyoke College undergraduate students will be involved in all phases of this project, from latex particle adsorption, characterization o0f surface topography, organic chemistry transformations of surface functional groups, determination of surface composition, to measurement and interpretation of wettability.

The introduction of polymer chemistry to chemical education at Mount Holyoke College is also proposed in order to respond to the new demand of the rapidly changing nature of chemical sciences. We need to get students excited about chemistry, and to reinforce the traditional disciplines of chemistry and show how they can be used. Over the next three years, the PI's efforts in this area will be focused on the following initiatives: mentoring undergraduates carrying out independent research in polymer surface chemistry, designing and teaching a polymer chemistry course, an integrated laboratory course, and a first-year honors tutorial on polymer chemistry, incorporating polymer chemistry into undergraduate introductory courses.
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DESCRIPTION: (provided by applicant) People are living longer than ever and the demand for organ and tissue replacement has never been greater. Because of this, a key issue that researchers in the biomaterials field face today is biocompatibility, in particular blood compatibility, of artificial implants in human bodies. Protein adsorption followed by cell adhesion and various undesirable biological responses occurs when most foreign objects contact body fluid. Designing surfaces that proteins do not adsorb to and that cells do not adhere to is the primary approach in improving biocompatibility of artificial implants. Two strategies for designing compatible artificial implants have emerged and are worth noting: incorporation of poly(ethylene glycol) to surfaces, designing biomembrane-like surfaces containing phospholipids or phospholipid-like moieties. These strategies work in certain cases, but the weaknesses in the current approaches are: (1) the lack of stability of the modified implants during long term application and (2) the lack of fundamental structure-biocompatibility relationships. The objective of the work proposed here is to address these weaknesses by using surface chemistry to design long-lasting biocompatible implants by chemically bonding poly(ethylene glycol) (PEG) and phosphorylcholine (PC) groups to poly(ethylene terephthalate) (PET) surfaces. Surface grafting of epoxide-terminated PEG on two amine-containing surfaces and surface cationic polymerization of ethylene oxide on PET-OH surfaces are two proposed methods to introduce PEG with controllable chain length and density to PET substrates. PC groups will also be introduced to PET surfaces. This is a completely new strategy for improving the biocompatibility of PET implants. To quantify the amount of PEG and PC on PET substrates, three surface characterization techniques will be used: contact angle, x-ray photoelectron spectroscopy, and attenuated total reflectance infrared spectroscopy. We will correlate surface structural information with surface properties by assessing the protein adsorption and cell adhesion behavior of variable chain length and density PEG- and PC-containing surfaces.

0216182
Dunn

This Major Research Instrumentation (MRI) grant supports the research needs of Mount Holyoke College science faculty through acquisition of a new scanning electron microscope (SEM) with a low-vacuum sample chamber and energy-dispersive spectrometer. A new environmental SEM (JEOL JSM-5610) will supercede an existing JEOL 35 CF SEM that is 17 years old and lacks beam stability, image quality and the capability to image hydrated or uncoated samples. Faculty from multiple departments including biology, chemistry and the earth sciences are all engaged in research that will make excellent use of a state-of-the-art ESEM. Specific studies that require high resolution textural and compositional analysis of materials include, taxonomic investigations of marine invertebrates (Rotifera, Copepoda and Cladocera), studies of latex coated industrial materials, studies of graphite-calcite carbon isotopic exchange during metamorphism as a proxy of the temperature of formation of metamorphic assemblages, compositional mapping of Fe-rich mantle phases to better understand deep earth chemical dynamics and redox conditions, and taxonomic investigations of agriculturally-engineered crops. This facility will also expand the resources available to Mount Holyoke's renowned educational program for women.
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With support from the Major Research Instrumentation (MRI) Program, the Department of Chemistry at Mount Holyoke College will acquire an atomic force microscope (AFM). This equipment will be used to explore (a) the impact of surface topography on wettability; (b) the effect of surface chemistry and energetics on protein adsorption using a combinatorial approach; (c) the structure and interactions of microbes at interfaces; and (d) donor-acceptor interactions in matched component systems.

Chemistry is a scientific discipline that studies structure and processes at the molecular scale. In the past, chemists learned to examine and elucidate molecular events by performing collective spectroscopy, that is, measuring average properties from solution or solid-state experiments. Modern techniques, including AFM, allow measurements at a much faster and smaller scale. AFM allows the direct observation and understanding of molecular events occurring in chemical and biological processes, enables the correlation of microscopic structures to macroscopic properties, and permits the design of materials with nanoscopic features. These studies will have an impact in a number of areas, including surface and organic chemistry, materials science and biochemistry.

This Nanotechnology in Undergraduate Education (NUE) award to Professor Sean M. Decatur at Mount Holyoke College is made by the Division of Chemistry in the Directorate for Mathematical and Physical Sciences and the Division of Undergraduate Education in the Directorate for Education and Human Resources to increase the experience of students in nanoscale science and to enhance their perspectives on the social, political, and ethical considerations regarding nanotechnology.

The project seeks to integrate topics on nanotechnology throughout the core chemistry curriculum and to involve undergraduates in research on phenomena at the nanoscale, while engaging the broader community in critical issues regarding nanotechnology. The project has four primary goals: (1) Developing new lab experiences for undergraduate courses. (2) Involving undergraduates in nanotechnology research. (3) Engaging the broader community in critical analysis and discussion of nanotechnology. (4) Creating a cross-disciplinary faculty working group on nanotechnology. Faculty involved in the project will meet regularly to read and discuss new literature related to nanotechnology from a variety of fields.

The project is designed so that students learn to make connections between the macroscopic and atomic level descriptions of matter by relating bulk properties to molecular structure through techniques for imaging and manipulating molecules at the nanoscale, such as atomic force microscopy (AFM) and directed self-assembly. These tools will be introduced in courses for the first two years of the chemistry curriculum (general and organic chemistry) and expanded upon in the advanced courses.

The project will sponsor a series of seminars involving nanotechnology, including speakers, who will address questions concerning the social, political, ethical, and historical implications of nanotechnology for a broad, interdisciplinary audience. Units on nanotechnology will also be added to a new interdisciplinary course on the History of Chemistry.

The proposal for this award was received in response to the Nanoscale Science and Engineering Education announcement, NSF 03-044, category NUE.

With support from the Major Research Instrumentation (MRI) Program, the Department of Chemistry at Mount Holyoke College will acquire a suite of instruments for the characterization and fabrication of materials, including equipment for photolithography, a light microscope, a differential scanning calorimeter, and an instrument for measuring dynamic light scattering. The equipment will be used in four research projects at Mount Holyoke, all involving undergraduate students: the preparation of surface supported microgels using photolithography; the characterization of random coil/beta- sheet/aggregate transitions in a prion peptide; the use of threefold organic acceptors as building blocks for new donor-acceptor assembled materials; and the study of self-assembly of weakly interacting colloids on patterned interfaces. In addition, the equipment will be used in laboratory experiments in a new upper-level elective course in nanotechnology and existing courses in experimental methods and chemical thermodynamics.

The research projects and laboratory experiments described in this proposal will be used to expose undergraduate students to problems and methodologies at the cutting edge of chemical science. The chemistry department at Mount Holyoke has a well-established track record for involving undergraduate women in productive research, and the proposed project will help to sustain and expand that effort. New curricular materials and pedagogical approaches developed with the instrumentation from this project will be disseminated to the broader chemical education community.

TECHNICAL SUMMARY:

Inspired by natures ability of constructing materials, the PI, Wei Chen, and her undergraduate students at Mount Holyoke College propose to impregnate metal nanoparticles in a poly(vinyl alcohol) hydrogel matrix with hierarchical structural control from nanoscopic to macroscopic levels. By using a diffusion-controlled approach and manipulating experimental variants, composites with hierarchical structural features from the nanoscale (particle size, uniformity, and density) to the macroscale (macroscopic color patterns as the result of variations of particle size and density in the gel matrix) will be designed and engineered. These composite materials combine the unique optical, electronic, and high surface to volume ratio characteristics of nanoparticles and flexibility and biocompatibility of hydrogels.


NON-TECHNICAL SUMMARY:

The proposed work of incorporating metal nanoparticles in a biocompatible hydrogel system has enormous applications in medicine, biomedical diagnostics, sensing, and imaging. Mount Holyoke College undergraduate students will be involved in all aspects of the work proposed, from material synthesis to characterization using both routine and sophisticated instrumentation. The exposure of undergraduate students to nanotechnology and materials chemistry is a response to the emergence of nanomaterials as a major theme of chemical science. The underlying concepts of the project are interdisciplinary, ranging from the disciplines of chemistry to engineering. Undergraduate researchers will have the opportunity to reinforce and apply the knowledge that they learn in the classroom. The interdisciplinary nature of the proposed work aims to attract more women to the field as well as to provide a vehicle for them to use Engineering knowledge to design processes to solve real world problems.

The research objective of this GOALI award is to develop an information-based hierarchical choice modeling approach for managing and analyzing consumer preference data from multiple sources. This approach will enable the transformation of qualitative marketing preferences to quantitative performance measures in order to manage the complexity of demand modeling for large-scale artifacts. Advanced probabilistic choice modeling approaches will be used to capture customer preferences and market heterogeneity. Model fusion (data enrichment) techniques will be developed to effectively combine revealed and stated preference data from various sources to improve prediction accuracy and model validity. Finally, the integration of the choice model into an enterprise-driven design framework will be demonstrated in the design of vehicle interior package dimensions, considering multidisciplinary tradeoffs.

If successful, the proposed research will offer a general demand modeling and enterprise-driven design approach that can be applied to large-scale systems, engineered consumer goods, and mobility/prosthetic devices. Our research will leverage the results from existing discrete choice analysis techniques in market research and transportation engineering, and extend their use in engineering design. The strong collaboration between the university and industry will ensure that the resulting technology is successfully transferred and implemented. The proposed research has far reaching consequences for design education by instilling rigor into capturing customers' preference in the context of product usage through analytical modeling. Results of the research will be incorporated into undergraduate and graduate design courses in mechanical engineering. Industry co-PIs will have significant involvement in the project through collaborations with the research team, service on student thesis committees, invited research seminar presentations, and guest lecturer opportunities.

[unreadable] DESCRIPTION (provided by applicant): A key issue that researchers in the biomaterials field face today is biocompatibility of artificial implants in human bodies. Protein adsorption followed by cell adhesion and various undesirable biological responses occur when most foreign objects contact body fluid. Designing surfaces that proteins do not adsorb to is the primary approach in improving biocompatibility of biomaterials. Of the few existing biocompatible materials, poly(ethylene glycol) (PEG) and phosphorylcholine-containing molecules are the most well-recognized and studied. The exploration of new materials for potential biomedical applications is a responsibility that is imperative for materials scientists to address. In the proposed work, surface-initiated ring-opening metathesis polymerization (SiROMP) of cyclic olefins in the vapor phase and subsequent hydroxylation reaction will be assessed as an approach to tether new materials to silicon substrates. SiROMP is an effective method to covalently attach functionalized linear polymer chains to substrates, however, the reported monomers undergoing SiROMP in solution have been limited to norbornene and its derivatives. Vapor phase SiROMP of cyclic olefins of varying degrees of ring strain (cyclopentene, cycloheptene, and cyclooctene) and of different degrees of unsaturation (cyclooctene, cyclooctadiene, and cyclooctatetraene) will be carried out in the proposed work. The tethered unsaturated polymers will be hydroxylated to yield alcohol-functionalized polymers; the -OH group density will be controlled by the ring size and the degree of unsaturation of the cyclic olefins used. The molecular weight of the polymers will be tuned by grafting time. Wettability and protein adsorption characteristics will be correlated to the molecular weight and the -OH group density along the hydroxylated polymer chains. The protein adsorption characteristics of these new materials will be compared to those of well-recognized biomaterials, such as PEG. With the proposed research we hope to open up new opportunities for the design of bio-relevant materials. The exploration of new materials for potential biomedical applications is a responsibility that is imperative for materials scientists to address. Alcohol-functionalized linear polymers with varying alcohol group densities will be designed and tethered to solid substrates by a new synthetic tool, surface-initiated ring-opening metathesis polymerization in the vapor phase of low ring-strain cyclic olefins, followed by hydroxylation of the unsaturated polymers. Wettability and protein resistant characteristics of these new materials will be studied and correlated with their molecular weight and alcohol group densities. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): The long-term goal of this research is to understand how the olfactory system encodes odor information, and how olfactory sensory codes are transformed sequentially through different processing stages along the central projection pathways. Olfactory coding and processing have been extensively studied with two major approaches: (1) electrophysiology of single neurons, which can record neural activity at any tissue depth, but blindly without knowing network context in reference to upstream coding patterns; and (2) CCD camera imaging of spatiotemporal pattern of activated glomeruli, which is ideal for revealing the initial glomerulus-based codes, but lacks single-cell resolution and deep penetration required for exploring odor codes beyond the glomerular layer. This grant is aimed at bridging such a gap between single-cell physiology and large-scale CCD camera imaging, so as to unify the two large datasets already available in the literature. First, using a new transgenic mouse model, we will provide a direct comparison between the pre- and postsynaptic odor maps within the glomerular layer, and test the hypothesis that lateral circuits intrinsic to this layer can support interglomerular lateral inhibition and/or excitation for initial odor-map transformation. Second, by combining in vivo two-photon calcium imaging and targeted single-glomerulus dye labeling, we will perform a systematic analysis of odor ensemble codes carried by the mitral/tufted cells associated with a common glomerulus. We will test the hypothesis that both the overall size and distribution pattern of a glomerulus-defined active cell ensemble can be effective coding factors for odor intensity at least and maybe also identity. Finally, by imaging the mitral cell population with diverse glomerular projections, we will analyze the cross-glomerular odor ensemble responses in the context of corresponding glomerular activation patterns. We will study how the glomerulus-based odor codes break down into distributed mitral-cell population codes, and ask what is the benefit of redistributing odor signals which have just converged via the nose-to-bulb projection. Collectively, these studies should not only have a significant impact on our understanding of the neural basis of odor processing and discrimination, but could also yield novel and more general principles on how the brain transforms neural codes for achieving sensory and perceptive functions. PUBLIC HEALTH RELEVANCE The sense of smell plays an important role in our daily life style involving flavor and fragrance appreciation. Dysfunction of the olfactory system happens in many human diseases such as eating-related obesity and early development of Alzheimer's disease. The general goal of this grant in understanding the neural basis of odor coding and processing will not only help the diagnosis and treatment of these diseases, but will also promote people's life quality in general. [unreadable] [unreadable] [unreadable]

The project, a collaborative effort involving SUNY at Buffalo, Pennsylvania State University, and Northwestern University, is combining concepts from archaeology with advances in cyber-enhanced product dissection to implement new educational innovations that will directly address the challenging global, economic, environmental, and societal aspects in an engineering curriculum. The approach builds upon the team's previous demonstration and assessment efforts in cyber-enabled product dissection-based pedagogy by developing and disseminating scalable learning materials, strategies, and educational innovations that develop students' understanding of the broader context of engineering. Specifically, they are (1) creating integrative in-class activities and learning materials based on a cyber-enabled product for engineering design-related courses that span freshmen through senior levels; (2) developing rubrics and assessment tools in core areas to ensure sustainable deployment with national impact; and (3) conducting hands-on workshops to foster dissemination of new teaching strategies based on product archaeology through faculty development and outreach. Evaluation efforts are examining the impact on student learning through assessments embedded in the actual learning material and exercises, the extent to which their materials are adopted by others, and the factors that facilitate or impede adoption by others. Broader impacts include aggressive dissemination through faculty workshops and focused K-12 outreach efforts targeting female high school students and technology and science teachers.

TECHNICAL SUMMARY

Polymer adsorption onto nanoparticles has both technological relevance and scientific significance. Considering the broad range of applications involving gold nanoparticles (AuNPs) and the nontoxicity and water solubility of poly(vinyl alcohol) (PVOH), it is surprising that adsorption studies of PVOH onto AuNPs have not been reported in the literature. An additional rationale for selecting PVOH is that it is commercially available with different molecular weights and extents of hydrolysis, i.e. different amounts of residual poly(vinyl acetate) (PVA) repeat units. The adsorption of PVOH and PVA segments onto AuNPs prepared by the common citrate reduction method is expected to be driven by hydrogen bonding and hydrophobic interactions, respectively. The dominant mode of interaction will depend on the relative energetics of the two processes in a given system. Polymer composition provides an additional control parameter for adsorption and increases the complexity of probing of the adsorption mechanism(s). Understanding the variants of PVOH/PVA adsorption onto AuNPs, such as polymer molecular weight, size of nanoparticles, polymer composition, polymer concentration, and adsorption time, will allow us to propose a robust method to impart the stabilization of AuNPs against variations in solution pH, ionic strength, and temperature. For our long-term interest of preparing self-assembled NPs in polymer thin films, PVOH may be too crystalline to function as an appropriate polymer matrix for particles to form organized arrays and PVA could be important in providing ?softness? to allow particle mobility in self-assembly. The understanding and methodologies developed in the AuNP-PVOH system are potentially extendable to other nanoparticle-hydrophilic polymer conjugates.

NON-TECHNICAL SUMMARY

Nanoparticles have the tendency to form aggregates in solution, due to their high surface area-to-volume ratio, resulting in the loss of their unique nanoscopic characteristics. Adsorption of a thin polymer layer onto nanoparticles is an effective approach to provide particle stabilization in their applications. In the proposed work, a water-soluble and nontoxic polymer, poly(vinyl alcohol), will be adsorbed onto gold nanoparticle surfaces from aqueous solutions, to prevent nanoparticles from aggregating in response to environmental perturbations in pH, ionic strength, and temperature. The funds requested in this proposal will support the PI?s efforts in research collaborations with undergraduate students at Mount Holyoke College and local female high school students over the next three years. The undergraduate and local female high school students will be involved in all aspects of the work described in this proposal, from design and synthesis to characterization using both routine and sophisticated instrumentation. In the process, researchers will be introduced to the interdisciplinary field of polymer chemistry and be exposed to the vitally important area of nanotechnology. Exposure of undergraduate students to research is important for both education and recruitment purposes. The outreach activities proposed ? having local female high school students involved in frontier research and local middle school students engaged in fun and enlightening polymer workshops ? will inspire and prepare more women to be future scientists and engineers.

The research objective of this award is to develop a Design for Calibration (DfC) methodology for enhancing identifiability in simulation models. Identifiability refers to the difficulty in separating two general sources of uncertainty - parameter uncertainty and model uncertainty - in predictive modeling. Parameter uncertainty results from imperfect knowledge of the underlying physical parameters, and model uncertainty results from approximations and other inaccuracies in a simulation model. To ensure proper identifiability of these uncertainties when combining abundant simulation data with limited physical experimental data, the research takes advantage of two key enabling factors, the first being the inherently multi-response nature of computer simulations, and the second being the availability of extensive simulation results prior to designing the physical experiment. Using spatial random field modeling within a Bayesian framework, the methodology will determine the best subset of response variables to measure experimentally and the most efficient combination of input settings to use over the experiments, with the objective of optimally enhancing identifiability of the uncertainties.

If successful, the results of this research will help ensure identifiability of predictive uncertainties in a manner that allows limited experimental resources to be used most efficiently. This is critically important in simulation-based engineering and science across all engineering disciplines for many reasons that extend beyond achieving good myopic prediction. Learning and distinguishing the true physical parameters and simulation model inaccuracies has broad-reaching implications for i) new product/process designs that are much more complex than the experimental testbed, ii) improving future generations of simulation code, and iii) providing more accurate prediction over a wider set of input regions. Because the methodology is not tied to a particular type of simulation code or application domain, it is expected to be widely applicable. This work will leverage the broad-based constituency of the interdisciplinary doctoral Predictive Science and Engineering Design cluster at Northwestern, through which multidisciplinary testbed applications will be drawn and the results disseminated throughout different engineering domains.

Technical Abstract

In the past 15 years, research into nanoreinforced polymers has exploded, providing numerous examples of property enhancements ranging from altered thermal, mechanical, electrical, diffusion, optical and other properties. The amount of experimental data and simulation data, compounded with the data on the individual constituent phase materials is staggering. At the same time, while some mechanistic principles underlying property changes have been slowly uncovered, our ability to both deeply understand the underlying principles and to design new nanostructured polymers with desired properties from known processing steps is severely limited by the lack of integration of the information. To determine the type of property changes that have been observed requires manual searching of online journal databases, full reading of the articles, and manual accumulation and then synthesis of the information. This approach ensures that many relevant papers and articles are overlooked and allows only rudimentary synthesis of data and understanding of the processing-structure-property relationships. The birth of the materials genome concept provides a new paradigm for developing understanding of materials and designing new material concepts. In this research project, we tackle this challenge in the domain of polymer nanocomposites. While the materials genome approach has had some success in the metals field, the polymers area is considerably less developed and no resources exist for nanocomposite systems. Yet with the infinite design space available to polymer nanocomposites, it is a prime system for a new data driven approach. The Intellectual Merit of the work is application of materials genome concepts to the complex material system of polymer nanocomposites, with the goal of uncovering the processing-structure-property relationships. The overarching framework is to consider the material response as a function of processing conditions, constituents, interactions and morphology. Specific accomplishments include 1) development of a data resource (NanoMine) for housing and exchange of polymer nanocomposite data, 2) development of reduced descriptor sets to characterize data and quantify structure, and development of new data mining methods to enable discovery of underlying material physics, 3) integration of simulation tools to augment experimental data and enable exploration of design concepts. The Broader Impacts of the work are the NanoMine data resource itself, the new data-driven approach for materials understanding and discovery, and through use of these tools the ability to make deeper connections between processing, resulting material morphology and properties. The creation of an open-source, freely accessible data resource will provide not only a fast and easy source of information, but will also link researchers together in new ways. The data driven approach applied to this one system of nanocomposites, will provide strategies that can be extended to other material systems, greatly extending its influence. We will also integrate research and education through interdisciplinary graduate education including a special project based course. We will include undergraduates in our research program. This cadre of graduate and undergraduate students will have an interdisciplinary approach to materials discovery. We will also reach out to the broader community through NU and RPI High School outreach days (such as Design Your Future Day and Career Day for Girls) and teach them about Materials Design and data driven research.

Non-technicalAbstract

Development of nanoparticle reinforced polymers in the past 15 years has created new materials with extraordinary properties - such as conducting yet transparent plastics, tennis balls that retain their bounce longer, and stiffer, stronger structural plastics for cars and airplanes. Yet the development of these advanced new materials has been very slow due to lack of integrated information, both experimental data and simulation tools. Currently, understanding the state of the field requires manual searching of online journal databases, full reading of the articles, and manual accumulation and then synthesis of the information. No resources yet exist for assembling the data, nor do tools exist to allow assembled data to be effectively mined for correlations, much less to enable rapid design of new materials. In this research, we will develop a data resource (NanoMine) for housing and exchange of polymer nanocomposite data and development of new data mining methods to enable discovery of underlying material physics. We will integrate of simulation tools to augment experimental data and enable exploration of design concepts. The creation of an open-source, freely accessible data resource will provide a fast and easy source of information, and will enable both fundamental new understanding of materials as well as much more efficient material design. The data driven approach applied to this one system of nanocomposites, will provide strategies that can be extended to other material systems, greatly extending its influence. We will also integrate research and education in several ways from K-12 through to practicing engineers.

The objective of this collaborative research project is to develop a microstructure-mediated design methodology that provides a seamless integration of design optimization, predictive materials modeling, processing and surface engineering, to enable accelerated discovery and development of new materials. Through the synergy of experts in engineering design, mechanics, and materials science, a descriptor-based computational microstructure design framework and a combined theoretical, computational, and experimental approach to design new microstructural systems with tailored system properties. Using emerging nanodielectric polymer systems as a testbed, final proof of concept will reside in design of filler morphology, interphase properties, and chemistry combinations for achieving specific mechanical and dielectric properties for a wide range of engineering applications. The computational microstructure design framework will create a shift from discovery-based materials development to systematic and computer-assisted materials design. This research will also make significant strides in predicting interphase behavior based on interaction of material constituents.

The results of this research could have important societal impact through innovations of new nanodielectric polymers used in electrical transmission and storage systems across a wide range of industries such as utility, energy, consumer electronics, and manufacturing. Since this research provides a general methodology for designing microstructural material systems, the techniques will transcend to broader applications and benefit a wide range of domestic and military applications. To disseminate the results to a broader community, a workshop on "Design of Emerging Microstructural Material Systems" will be organized. Research will be integrated with education and students will have the opportunity to participate in interdisciplinary materials system design projects that offer innovation and leadership experiences.

NON-TECHNICAL SUMMARY:

Poly(vinyl alcohol) (PVOH), a nontoxic and water-soluble polymer, spontaneously attaches itself to silicone substrates from water solution and forms "fractal" (tree-branch like) structures from nanoscopic to macroscopic scales. The objectives of the proposed work are to explore the formation mechanism of PVOH fractals on silicone substrates and to probe the material and experimental factors controlling the structural features of PVOH fractals. The polymer fractal formation dynamics will be imaged during their actual generation using optical microscopy; the fractal structures from the nanometer to micrometer scales will be characterized by various microscopy techniques. Wettability and other surface characteristics of the silicone substrates, before and after PVOH adsorption, will also be analyzed to assess the effect of the fractal polymers on substrate properties. The funds requested will support the proposed scientific research involving a number of undergraduate students at Mount Holyoke College and local female high school students over the next three years. With the proper training, mentoring, and encouragement, the students will gain competency and confidence in scientific research and will be better prepared for the next phase of their educational endeavors.


TECHNICAL SUMMARY:

Poly(vinyl alcohol) (PVOH) spontaneously adsorbs from aqueous solution to silicone substrates and forms unusual fractal structures at multiple length scales. The crystalline nature of PVOH and the unique properties of silicone thin films (molecular flexibility, low surface tension but high water compatibility) will be probed in exploring the conditions for fractal formation. The dependence of fractal features (size, density, and dimensionality) on experimental variants (silicone thickness and composition, PVOH molecular weight and degree of hydrolysis, and adsorption parameters) will also be the focus of the proposed work. Atomic force and optical microscopy will be used to image dynamically PVOH fractal formation on various silicone substrates in-situ and to analyze the fractal features from nanoscopic to macroscopic scales. Contact angle goniometry and ellipsometry, in addition to various other surface techniques, will be utilized to characterize the silicone substrates, before and after PVOH adsorption, to assess the effect of the fractal adsorbed polymers on substrate surface chemistry and properties. The proposed research will not only establish a new system to prepare fractally branched polymers with controlled structural features, but will also provide insights on material and experimental requirements for fractal polymer formation. The funds requested will support research involving a number of undergraduate students at Mount Holyoke College and local female high school students over the next three years.

The complexity of engineered systems such as aerospace vehicles, automobiles, and advanced materials systems has reached a tipping point that challenges existing design and analysis methods. Simplified design models, applied in traditional paradigms, are inadequate for capturing complex system behaviors. Moreover, high-fidelity computer simulation models and experimental tests cannot be fully applied in many situations, due to their high costs. As a result, there is a great need for systematically fusing information from multiple sources, including simulation models with multiple levels of fidelity, and for deciding how best to conduct further simulations at each stage of the design process. This research will create a new decision-making framework to address this need and to guide the design of complex engineered systems. The resulting method is expected to increase the value of the design process in industries such as aerospace, automotive, energy, and consumer electronics by reducing the occurrence of undiscovered problems that occur late in a development cycle and decreasing the budget and schedule required for the design process. The project will also provide interdisciplinary research training and education across aerospace, mechanical, and industrial engineering.

The intellectual significance of this research is to approach the design of a complex system as an information-seeking and knowledge-generation (learning) process that can be modeled as a stochastic discrete-time dynamical system. Information theory and decision science are integrated to make design decisions that involve not only selection of system attributes, but also choices about subsequent information-seeking actions in a design process. An overarching Bayesian spatial random process modeling framework will be established to fuse heterogeneous information from multifidelity simulations and experiments with uncertainty quantification, where the fidelity of models can be either clearly ranked (hierarchical) or not (nonhierarchical). Approaches based on multidisciplinary statistical sensitivity analysis and multidisciplinary uncertainty analysis will be established for managing the couplings and complexity inherent in fusing information across fidelities and disciplines, while maintaining disciplinary autonomy in distributed analyses. The dynamic decision making framework will provide a uniform accounting for many different types of uncertainties, and decision functions grounded in expected utility theory are formulated to guide subsequent design actions. A further critical contribution of this research is to develop heuristic-based strategies for managing the complexity in solving the daunting optimal decision making problem. The framework will be assessed on a testbed problem involving the design of a distributed electric propulsion aircraft concept.

Polymer nanocomposites are highly tailorable materials that, with careful design, can achieve superior properties not available with existing materials. Most polymer nanocomposites are developed using an Edisonian (trial and error) process, severely limiting the capacity to optimize performance and increasing time to implementation. The solution is a data-driven design approach. As an example, this Designing Materials to Revolutionize and Engineer our Future (DMREF) project will design new material systems that simultaneously optimize for dielectric response and mechanical durability, a combination currently not achievable but necessary for high voltage electrical transmission and conversion. These new materials will have a significant economic impact on society because they will enable higher efficiency generation and transmission of electricity. More broadly, this new design approach will result in new nanostructured polymer material systems that will impact a wide range of industries such as energy, consumer electronics, and manufacturing. To ensure broad access to this work, the data, tools and models developed will be integrated and shared through an open data resource, NanoMine. The team will interact with the scientific community to create an integrated virtual organization of designers and researchers to test and improve the models. Educational components will reach undergraduate and graduate communities via interdisciplinary cluster programs at the two institutions, and provide undergraduate research opportunities and web based instructional modules and workshops.

The research is based on a central research hypothesis that using a data-driven approach, grounded in physics, allows integration of models that bridge length scales from angstroms to millimeters to predict dielectric and mechanical properties to enable the design and optimization of new materials. Data, algorithms and models will be integrated into the new and growing nanocomposite data resource NanoMine to address challenges in data-driven material design. This research will result in advancements in three areas. First, integrating a broad set of literature data and targeted experiments with multiscale methods will enable the development of interphase models to predict local polymer properties near interfaces considered critical for modeling polymer composites. Second, a hybrid approach utilizing machine-learning to bridge length scales between physics-based modeling domains will be used to create meaningful multiscale processing-structure-property relationship work flows. And, third, a Bayesian inference approach will utilize the knowledge contained in a dataset as a prior probability distribution and guide 'on-demand' computer simulations and physical experiments to accelerate the search of optimal material designs. Case studies will demonstrate the data-centric approach to accelerate the development of next-generation nanostructured polymers with predictable and optimized combinations of properties.