Glenn H. Fredrickson, Ph.D. - US grants

This Presidential Young Investigator Award will focus on theoretical studies of polymeric systems; particularly, the phase and interfacial behavior of polymeric materials. Three general subject areas will be addressed: (1) Phase behavior of blends with block copolymers; (2) Interfacial properties of liquid crystal copolymers; (3) Phase separation of polymer solutions under flow.

This is a CRISP (Combined Research - Industrial Sabbatical Program) proposal for a joint project between the UCSB and AT&T Bell Laboratories. The main objective is to control the molecular structure and orientation of liquid crystalline polymers (LCPs) during injection molding in order to obtain precise manufactured parts and increased electrical conductivity. The research approach combines molecular theory modeling to predict the behavior of LCP melts, experimental studies of their rheological and optical microstructural properties, and various precision molding processes. The selected model thermotropic LCP is well suited for rheological and structural studies, and will open a more fundamental approach to characterize the LCPs as compared to previous studies. The project will use resources at the UCSB and AT&T Bell Laboratories. According to the CRISP requirements, the PI will submit a report to NSF after the completion of the industrial visit of Prof. Pearson in order to evaluate a possible redirection of research. Applications include high accuracy interconnection parts used in the fiber optics and electronics industry, with an immediate use in the construction of the AT&T nationwide data network. The selected LCP is the base for development of an "enabling" technology in high precision molding, with optoelectronic devices as a first application area.

9407741 Pincus This theoretical research will be carried out at both the University of California at Santa Barbara and the University of California at Los Angeles. Analytical and simulational investigations will be done on polymers which are soluble in aqueous solvents because of hydrogen bond formation between the solvent molecules and the moities on the chain, e.g., oxygen on the backbone of polyethylene oxide. The particular focus will be on the interplay between the chemical nature of the hydrogen bond and the hydrophobic interaction associated with the hydrocarbon backbone. These uncharged hydrosoluble polymers have important applications to technological issues associated with the use of inorganic solvents and also as models for the activity and function of a class of biopolymers. The work will be extended to copolymers where one part has hydrogen bonding character and the other part is a more typical hydrocarbon. Such copolymers are potential candidates for vesicle stabilizers in drug delivery systems. %%% This theoretical research will be carried out at both the University of California at Santa Barbara and the University of California at Los Angeles. Analytical and simulational investigations will be done on polymers which are soluble in water. ***

9505599 Fredrickson With the advent of powerful new surface characterization techniques, a number of experimental groups have reported on the surface segregation and wetting behavior of multicomponent polymer blends, as well as block and random copolymers. Surface energy differences between components are generally assumed to be responsible for producing the inhomogeneous composition profiles in such systems. Very recent experiments on model polyolefin blends and copolymers, however, have shown that a strong correlation exists between interfacial thermodynamics and the difference in conformational properties (i.e., backbone flexibilities) of the components, leading to an alternative entropic explanation for surface segregation. Theoretical calculations based on the self-consistent field theory of Edwards will be performed to place these experimental observations on a sound theoretical footing. Besides exploring surface enrichment in such "conformationally asymmetric" polymer blends and copolymers with small heats of mixing (e.g., polyolefins), calculations will be performed to investigate interfacial thermodynamics and wetting behavior in blends of "architecturally asymmetric" polymers, such as mixtures of linear and star polymers composed of the same chemical repeat unit. An examination of surface enrichment is also planned for molten polymer blends that contain star-block copolymers, and for which broken conformational and architectural symmetries may compete. The objective of these studies if to develop structure-property relations that will facilitate the rational design of polymer interfaces for engineering applications. The theoretical work proposed will be coordinated with parallel experimental efforts currently underway. %%% Theoretical research will be conducted on the properties of polymer surfaces. In particular, the question of why certain types of polymers tend to migrate to the surfaces of polymer mixtures and solids will be explored. While having fundamental interest, this problem is also of high technological interest since it impacts our ability to coat and paint plastics. ***

9870128 Pine The objective of this research is to develop a fundamental understanding of shear thickening and flow-induced gelation in associating polymer solutions. A coordinated, three-pronged approach is proposed which involves the synthesis of new functionalized polymers, measurements of rheological and shear- induced structural changes, and theory. Highly monodisperse polymers, with well defined molecular weights, will be synthesized and will be quantitatively end-capped with functional groups designed to promote associations between polymers. The functional groups will be placed in one of four configurations: (1) at one end of each chain or (2) at both ends of the chains or (3) halfway along the backbone of the chains or (4) at both ends and halfway along the chain length. The degree of branching at the physical crosslinks will be controlled using metal ions with different coordination numbers. The degree of the association (or lifetime of associations) will be controlled by the addition of cosolvents which serve as "poisons" for the associating groups. In addition to extensive rheological measurements of shear and normal stresses, in situ direct measurements of the degree of association will be performed as a function of shear rate using uv/vis absorption spectroscopy. In situ measurements of flow-induced alignment of polymers will be performed using birefringence. Small and large angle light scattering measurements of the static structure factor S(q) as a function of shear rate will be used to follow flow-induced structural changes. The growth of the shear-induced gel under shear flow will be followed using the newly developed light scattering microscopy technique. The experimental work will be closely coordinated with an intensive program of theoretical research. Theoretical and experimental studies will commence with work on a model polymer solution in which each chain contains a single, terminally-attached sticker and progress towards more complex sticker placement as well as issues of network formation and gelation. %%% Associating polymer solutions find wide use in industrial applications as viscosity modifiers, anti-misting or anti- splatter agents, coagulants in coatings, and blocking agents in oil recovery. The utility of these systems stems from a number of important physical properties, including their ability to significantly enhance solution viscosity with the addition of very small amounts of polymer, their ability to control and even reverse the reduction of viscosity with temperature (this capability is important for many lubricants), their ability to suppress misting and splatter, and their ability to gel under certain conditions. The purpose of this research program is to develop an understanding of the molecular factors which determine the physical properties of these systems in order to engineer these systems for practical industrial applications. ***

9870785 Fredrickson This is a theoretical grant in polymer science. The focus is on the time-dependent structural evolution properties of multicomponent polymeric systems. Projects will include (1) macromolecular solution templating and (2) stress- concentration coupling and phase separation kinetics of linear/branched polymer blends. In each area, the proposed research is designed to elucidate fundamental knowledge that will guide practical macromolecular materials design, optimization, and processing. This theoretical program will be coordinated with experimental activities underway at Santa Barbara and Minnesota. %%% This is a theoretical grant in polymer science. The focus is on the time-dependent structural evolution properties of multicomponent polymeric systems. Projects will include (1) macromolecular solution templating and (2) stress- concentration coupling and phase separation kinetics of linear/branched polymer blends. In each area, the proposed research is designed to elucidate fundamental knowledge that will guide practical macromolecular materials design, optimization, and processing. This theoretical program will be coordinated with experimental activities underway at Santa Barbara and Minnesota. ***

A comprehensive theoretical and computational investigation of the equilibrium properties on inhomogeneous polymers will be carried out. The research will build on the recent developments by the PI and co-workers on the field-theoretic computer simulation (FTS) method, enabling numerical investigations of field theory models of polymers and complex fluids without any simplifying assumptions such as the mean-field approximation. The research will have the following components: (1) Foundations of the FTS method: This will include development of improved algorithms for solving the complex diffusion equation central to the method and development of efficient numerical schemes for time integration of the complex Langevin equations used to implement chemical potential field updates. Real-space renormalization group theory will also be applied to isolate lattice cutoff effects and to enable systematic coarse-graining of polymer solution models. (2) Micelle phases in copolymer alloys: The FTS method will be applied to investigate micelle formation in block copolymers-homopolymer blends near mesophase unbinding transitions, where mean-field theory is expected to fail. (3) Block and graft copolymer systems with chemical disorder: Simplified models of poydisperse star-block and graft-block copolymers will be constructed in which both annealed and quenched disorder averages can be exactly carried out. The models will be numerically and analytically investigated to study the differences in self-assembly behavior between systems with the two types of disorder, the role of fluctuation effects, and the existence of compositional glass transitions. The overall objective is to gain a fundamental understanding of how chemical disorder, unavoidable in commercial copolymer materials, influences structure and thermodynamics. (4) Defect control in thin copolymer films: Translational and bond-orientational order will be examined in FTS simulations of block copolymer films with special perimeter boundary conditions. The results will be used to assess the efficacy of graphoepitaxy for creating defect-free copolymer films that can be used in ultra-high density patterning of advanced electronic, optical, and magnetic devices. The research will be closely coupled with experiments in the laboratory of E.J. Kramer at UCSB.

The research will involve training of graduate students and post-doctoral researchers. The fundamental understanding gained through this project will be leveraged through a new Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that will address computational design of industrial polymer and complex fluid formulations.
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A comprehensive theoretical and computational investigation of the equilibrium properties on inhomogeneous polymers will be carried out. The research will involve training of graduate students and post-doctoral researchers. The fundamental understanding gained through this project will be leveraged through a new Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that will address computational design of industrial polymer and complex fluid formulations.
***

ABSTRACT
CTS-0304596
G. Fredrickson, U of CA Santa Barbara

This exploratory research project will assess the feasibility of conducting direct numerical simulations of nanostructure development during processing of complex fluid formulations of importance in several industries, such as paints, coatings, polymer alloys, cosmetics and processed foods. Advances in synthetic methods for producing copolymers have enabled exciting new multiphase complex fluids formulations in which the domain size falls in the nanometer range, 1-100 nm, and the geometrical arrangement of the domains can be precisely controlled by varying copolymer architecture, processing and composition variables. The framework for the simulations will be a field theoretic technique recently developed for equilibrium self-assembly and phase behavior, which will be extended to non-equilibrium systems that include couplings to stress strain and momentum density fields. The approach will be validated against experimental data on shear-induced microstructure development in poly(vinylcyclohexane)-poly(ethylene) multiblock copolymers, which have emerged as top candidates for advanced optical media resins.

The project is being funded by CTS/ENG and DMR/MPS.

The Materials Research Science and Engineering Center (MRSEC) at the University of California at Santa Barbara (UCSB) addresses fundamental problems in materials science and engineering that are important to the scientific community, society and the future economic growth of the United States. Current areas of interest include the support of interdisciplinary and multidisciplinary materials research and education of the highest quality in the areas of new semiconductors for microelectronics, novel nanostructures for high speed communication devices and advanced polymeric materials. A prime driver behind the research activities of the UCSB MRSEC is to address problems of a scope and complexity requiring the advantages of scale and interdisciplinarity that can only be provided by a campus-based research center. The MRSEC has a leadership role in Educational Outreach programs and in the development of Industrial and International Collaborations on the UCSB campus. It provides undergraduate research opportunities, graduate student training, outreach to K-12 students and teachers, and community outreach. The outstanding Central Facilities program plays a fundamentally important role in the research of all MRSEC programs and additionally has a broad impact on the materials research community at UCSB, local and national companies, and government laboratories.

The MRSEC consists of the following IRGs: IRG-1: Specific, Reversible and Programmable Bonding in Supra- and Macromolecular Materials identifies new experimental and computational methods for precisely controlling the structure and properties of materials based on directed and reversible interactions.. IRG-2: Oxides as Semiconductors focuses on the theory, growth, and application of ultra-pure semiconducting oxides. IRG-3: Soft Cellular Materials seeks to use tailor made/functionalized nanoparticles and block copolymers, in association with polymer blends, to develop new soft materials with precisely controlled cellular structures. IRG-4: Nanostructured Materials by Molecular Beam Epitaxy will examine the development of all-epitaxial metal/semiconductor nanocomposite systems for potential applications in high speed and Terahertz technology.

Participants in the Center currently include 30 senior investigators, 7 postdoctoral associates, and 24 graduate students from seven departments. Professor Craig Hawker directs the MRSEC.

TECHNICAL SUMMARY:
This award supports computational and theoretical research and education in the area of polymer simulation. This project will build on the recent development by the PI and co-workers of the "field-theoretic simulation" (FTS) method, enabling numerical investigations of field theory models of polymers, complex fluids, and soft materials without resorting to the mean-field approximation. The proposed research encompasses both fundamental and applied components.
. Foundations and extensions of the FTS method. This research thrust will include development of improved numerical schemes for time integration of the stochastic "complex Langevin" equations used to implement potential field updates. We also propose to develop a new "ground state-FTS" technique that should dramatically accelerate simulations of strongly overlapping polymer solutions (neutral and charged) in the semi-dilute and concentrated regimes.
. Numerical renormalization group theory. We propose to implement pseudospectral numerical RG transformations in tandem with complex Langevin simulations of polymer field theories. This will facilitate the isolation of lattice cutoff effects and enable systematic coarse-graining of polymer solution models. The PI envisions applications to block copolymers in selective solvents.
. Hybrid particle-field simulations. We propose to develop a new class of simulations for treating nanoparticles or colloids embedded in structured polymer fluids. The particles are treated as "cavities" in the fluid fields and the particle coordinates are retained along with the fluid field variables.
. Defects in confined copolymer films. Translational and bond-orientational order will be examined in FTS simulations of block copolymer films with perimeter boundary conditions. The results will be used to assess the efficacy of grapho-epitaxy for creating defect-free copolymer films that can be used in ultra-high density patterning of advanced electronic, optical, and magnetic devices. The proposed research will closely couple with an experimental program underway in the laboratory of Edward J. Kramer at UCSB.
The PI will continue in his tradition of effective graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under the proposed project will be further leveraged through the Complex Fluids Design Consortium (CFDC) at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

NON-TECHNICAL SUMMARY:
This award supports computational and theoretical research and education in the area of polymer science using computers to simulate polymer materials and polymer-related phenomena. The PI plans to continue his work on fundamental theoretical advances and new algorithms aimed at extending a simulation method he developed and at developing new simulation methods for inhomogeneous polymer materials, complex fluids, and soft materials. These methods are needed to handle essential physics that arises across diverse length and time scales in these materials and often makes reliable computer simulation difficult. In an effort coupled to experiment, the PI plans to apply these newly developed advanced simulation methods to thin films of block copolymers and to investigate a promising experimental technique for creating nearly perfect copolymer films that can be used as a template to synthesize inorganic nanowires, nanodots, and other nanoscale structures.
The PI will continue in his tradition of effective graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under the proposed project will be further leveraged through the Complex Fluids Design Consortium (CFDC) at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

TECHNICAL SUMMARY
The Division of Materials Research and the Division of Mathematical Sciences contribute funding to this award. It supports theoretical and computational research and education that will develop the "field-theoretic simulation" method, enabling direct numerical investigations of field theory models of polymers, complex fluids, and soft materials without resorting to the mean-field approximation. The PI aims to make fundamental, transformative breakthroughs in understanding and methodology that will enable field-theoretic simulation studies of entirely new classes of polymers and soft materials. Specific components of the project include:
+ Chebyshev spectral methods. This research thrust will explore the use of Chebyshev spectral collocation methods in solving polymer self-consistent field theory equations for thin polymer films. The high accuracy provided by Chebyshev methods could facilitate simulations of multi-layer block copolymer films that are currently inaccessible, but highly relevant to the rapidly developing field of block copolymer lithography.
+ Grafted polymer layers. This thrust aims to develop novel approaches and numerical methods for conducting high resolution field-theoretic and self-consistent field theory simulations of grafted polymer layers. An expected outcome of this work is computational tools that will revolutionize ligand design in polymer-grafted nanoparticles, prediction of the structure and assembly of polymer functionalized nanoparticles and colloids, and guide "grafted from" nano-patterning schemes for microelectronics fabrication.
+ Free energy estimation. This research thrust will develop theoretical and computational strategies for computing absolute and relative free energies in field-based simulations. Such methods will enable the determination of phase diagrams, energy landscapes, and kinetic pathways for broad classes of soft material systems that defy conventional approaches.
+ Systematic coarse-graining method. The PI aims to develop methods for systematic coarse-graining of polymer field theories in conjunction with FTS simulations. This will facilitate the isolation of lattice cutoff effects and enable simulations of diverse families of equilibrium polymeric fluids on unprecedented length scales.

This award supports graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under this project will be further leveraged through the Complex Fluids Design Consortium (CFDC) at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

NONTECHNICAL SUMMARY
The Division of Materials Research and the Division of Mathematical Sciences contribute funding to this award. It supports theoretical and computational research and education that will extend develop new theoretical and advanced computer simulation methods to study systems composed of polymers which are long chain-like molecules. Some examples include DNA and the fundamental building blocks of plastics. The PI?s research includes the application of these computer simulation methods to the design of new materials based on polymers, for example plastics and materials composed of small organic or inorganic particles in a matrix composed of polymers.

This award supports graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under this project will be further leveraged through the Complex Fluids Design Consortium (CFDC) at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."
Proposal #: 09-60316
PI(s): Brown, Frank, L.; Fredrickson, Glenn, H.; Garcia-Cervera, Carlos; Gilbert, John, R.; Van de Walle, Christian, G.
Institution: University of California-Santa Barbara
Title: MRI-R2: Acquisition of a High Performance Central Computing Facility at UCSB
Project Proposed:
This project, acquiring of a computational cluster to replace a six-year-old system, allows access to fast mid-sized parallel computation to dozens of researchers and serves as the institution's primary resource for parallel computation. The system is structured for a variety of uses. Standard MPI computation is carried out with a tightly coupled cluster of quad core processors, while 'fat nodes' with 256 GB of RAM as well as local high speed disk storage service jobs that require large shared memory. Researchers actively developing codes can take advantage of the unique performance characteristics of GPU (graphics processing) nodes. The system will have several NVidia Tesla nodes.
The users of the system are drawn from all five departments of the College of Engineering (Chemical Engineering, Computer Science, Electrical & Computer Engineering, Materials, and Mechanical Engineering), seven departments of the Division of Mathematical, Life and Physical Sciences (Chemistry & Biochemistry, Earth Science, Ecology Evolution & Marine Biology, Mathematics, Molecular Cellular & Developmental Biology, Physics, and Psychology), as well as the departments of Economics, Geography, and Media Arts & Technology from the Division of Humanities and Social Sciences. In addition, the system supports research in eight campus centers: Allosphere Research Facility, the California NanoSystems Institute, the Center for Polymers and Organic Solids, the Institute for Crustal Studies, the Kavli Institute for Theoretical Physics, the Materials Research Laboratory, the National Center for Ecological Analysis & Synthesis, and the Neuroscience Research Institute.
The new system will be housed in the same location as the previous one where the same successful administrative and maintenance procedures used for the past six years will be applied. The proposed cluster will be accessible via the UC Grid, a web portal interface that makes high performance computing resources easy to use from desktop machines (PCs or Macs). The acquired system will come with a three-year warranty. Prior experience has shown that only a small number of nodes are expected to malfunction during the useful lifetime (> 3 years) of the cluster.
Broader Impacts:
The research enabled by the campus-wide facility, interdisciplinary and collaborative in nature, is available to the broad research community. The large majority of users, roughly 75%, consists of postdocs, graduate students, and undergraduates (5%), allowing this award to accomplish NSF's longstanding goal of integrating research and education. Outreach to K-12 takes place via a new initiative, The School for Scientific Thought (SST), an extension to the Let's Explore Physical Sciences (LEAPS) Program. Under the SST Program UCSB science and engineering graduate students design and teach a course for an audience of high school students on Saturdays. In addition, many of the faculty associated with this proposal participate in the UC Leadership Excellence through the Advanced Degrees program that has increased the number of underrepresented students in science and engineering at UCSB.

In this collaborative project, four scientists at the University of California - Santa Barbara will investigate the design, synthesis and incorporation of new "electroactive polymer surfactant" (EPS) molecules in all-organic polymer photovoltaic materials. The aim of this research is to overcome some of the key stumbling blocks that have plagued other researchers investigating polymer photovoltaic materials, based upon bulk heterojunction systems. The work will be organized around the following three goals: (1) the development of physics-based models and efficient numerical methods for the prediction of phase separation in blends of rod-like polymers with multifunctional copolymer surfactants; (2) the synthesis of new homopolymers and functional block copolymers/oligomers comprising p-type and n-type backbones with a central electronically active moiety, using the design characteristics from (1); and (3) the characterization of the morphology of the blends as a function of composition and process conditions. The Principal Investigators will simultaneously develop a multifaceted educational program in solar energy research, including programs for high-school teachers, workshops for young scientists, and international collaborative experiences for graduate students.

Efficient conversion of solar to electrical energy is likely to be one of the most important means of powering the planet in a sustainable way. Current materials for the conversion of sunlight to electricity are hampered by low efficiency and high cost. Work like that proposed in the present proposal seeks to find new alternatives that circumvent these problems. In particular, organic polymer (plastic) photovoltaic materials show promise as inexpensive alternatives to conventional semiconductor photovoltaic materials. Besides producing new kinds of materials for solar energy conversion, the Principal Investigators of this proposal hope to produce new kinds of scientists with the interdisciplinary expertise needed to make significant contributions to challenging scientific as well as societal problems.

TECHNICAL SUMMARY
This award supports theoretical and computational research and education to develop simulation methods for polymers, complex fluids, and soft materials beyond mean field theory. This research builds on the recent development of the field-theoretic-simulation method by the PI and co-workers. In this project, the PI aims to make fundamental, transformative breakthroughs in understanding and methodology that will enable field-theoretic-simulation studies of entirely new classes of polymers and soft materials. Specific thrusts of the project include:

1. Systematic coarse-graining methods. Methods will be developed for coarse graining polymer field theories in conjunction with field-theoretic simulations. Force matching techniques from the protein modeling community will be integrated with numerical renormalization group methods to accurately parameterize field theory models of soft materials on successively coarser computational grids. This methodology will enable simulation studies of diverse families of nano- and meso-structured polymeric fluids on unprecedented length scales.

2. Coherent states formalism. A new 'coherent states' representation of polymer field theory models will be investigated as a framework for numerical simulations. The coherent states approach utilizes stochastic fields that resemble forward and backward polymer propagators. Among other potential advantages, the proposed framework has a less complex analytic structure that could facilitate numerical coarse-graining.

3. Computational framework for nucleation studies. The PI aims to integrate field-theoretic simulations, coarse-graining techniques, and newly developed minimum energy path methods to estimate kinetic barriers and rates of phase transformations in nanostructured soft materials. The work will go beyond traditional mean-field approaches and thus allows the treatment of fluctuation mediated transitions. Relevant applications include the estimation of defect annealing rates in directed self-assembly approaches to microelectronics patterning with block copolymers.

This award supports graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials and polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained through this project will be further leveraged through the Complex Fluids Design Consortium, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

NONTECHNICAL SUMMARY
This award supports theoretical and computational research and education to develop computer simulation methods to study materials composed of polymers which are long chain-like molecules. Some examples include DNA and the fundamental building blocks of plastics. The simulation technique is complementary to methods that aim to directly simulate the interacting polymers and their motions. The PI?s research includes the application of these computer simulation methods to the design of new materials based on polymers, for example plastics and materials composed of small organic or inorganic particles in a matrix composed of polymers. Advanced computer simulation methods for polymers offer the potential to better utilize the tendency of polymers to assemble themselves into intricate and complex structures at the microscopic level to make microelectronics, sensors, solar energy converters, and other devices.

This award supports graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials and polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained through this project will be further leveraged through the Complex Fluids Design Consortium, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

****Technical Abstract****
This computationally driven discovery program aims to disrupt the status quo for the design of multiblock materials. The research centers on the marriage of pseudo-spectral self-consistent field theory (SCFT) and real-space genetic algorithms (GAs), with a tight coupling to experimental synthesis and characterization. While widely used in polymer science and bioinformatics, respectively, SCFT and GAs have not been previously integrated to tackle problems of block polymer discovery and design. The approach adopted here addresses the challenges of large parameter spaces and polymorphism. It also solves the "inverse problem" of identifying multiblock sequences and compositions that can produce a desired nanoscale morphology, without resorting to exhaustive, unguided searches through parameter space. The computational effort is synergistically and iteratively combined with an experimental program that includes state-of-the-art synthesis, processing, and characterization tools. The experimental work will validate the computational methodology, including parameterization of the models, and provide inspiration for attractive and synthetically accessible design targets. This combined approach will dramatically reduce the timescale for discovery, design, and deployment of new multiblock polymers as advanced functional materials.

****Non-Technical Abstract****
This collaborative effort between researchers at the University of California, Santa Barbara and the University of Minnesota will develop discovery tools that will enable the rational, computationally-assisted design of multiblock polymers for applications in medicine, microelectronics, separations, and energy production and storage, among others. Complicating factors in this class of soft materials are the myriad parameters that dictate molecular architecture, block sequence, and interactions and the wide range of self-assembled nanostructures that are possible. Through a concerted and iterative combination of theory, simulation, and experiment, global optimization tools will be devised and validated to predict the forward and reverse relationship between polymer architecture and nanostructure. The discovery tools developed in this program will be made widely available to the industrial and academic polymer materials community through a web-based job submission program hosted at the Minnesota Supercomputer Institute, and a searchable database will be constructed from the structure/sequence/morphology maps that result over the course of the project. Outreach to industry will be accomplished by leveraging the established and highly successful industrial consortiums at UCSB (Complex Fluids Design Consortium) and UMN (IPrime). Personnel on the project will be trained in and enhance the rich multidisciplinary research environments afforded by the existing MRSECs at UMN and UCSB.
This award is funded by the Division of Materials Research (DMR) and the Division of Mathematical Sciences (DMS).

SUMMARY
Modeling realistic polymeric and soft matter systems requires coverage of time intervals from nanoseconds to seconds or minutes. Even with modern supercomputers, such a wide dynamic range can only be achieved by performing multi-scale modeling that couples atomistic molecular simulations with coarse-grained or field-based simulations in a self-consistent manner. Advances in theory, modeling, computation, and data-mining are beginning to offer a foundation for the rational design of soft matter and polymers, and their assemblies at nanometer to macroscopic scales.
Many challenges remain in interfacing disparate methods appropriate at different scales and in managing the massive data sets arising from tandem use of multi-scale simulations and high-throughput experimentation, including the establishment of standards for data collection, data mining and analysis, and storage.
This award support provides support for a workshop to be held at the University of California, Santa Barbara (UCSB) on the topic of opportunities and challenges for theory and simulation related to the first-principles design of polymers and soft materials. A diverse group of participants will be drawn broadly from academic physics, chemistry, and materials engineering disciplines, along with representatives from synergistic fields such as biology and applied mathematics. Approximately 10% of the proposed participants are from outside the US and several are employed by or have experience in industry. The workshop will be held Sunday, October 20 through Tuesday, October 22, 2013.
The workshop aims to (i) identify the major theoretical and computational challenges relating to the first-principles design of broad classes of soft materials and polymers; (ii) identify the missing tools/methods necessary to address these challenges and the steps required to develop the methods; (iii) construct a vision for how theory, computation, and experiment can interact synergistically to discover new materials; and (iv) elaborate the theoretical advances and cyber infrastructure needed to enable more effective synergistic interaction.
The workshop will include the identification of opportunities that lie at the interfaces with other fields, such as biology, energy production, storage and conversion, and water purification and reuse; the identification of materials design problems of importance to industry and methods for strengthening academe-industry-national lab partnerships; and strategies for educating the next generation of scientists to be trained to work effectively at this scientific frontier. A report will summarize the workshop and be disseminated to the broader community.

Nontechnical Summary

This project will build on recent developments by the PIs and co-workers of the field-theoretic simulation method, enabling direct numerical investigations of field theory models of polymers and soft materials without approximation. This framework permits efficient computer simulations to be conducted for a wide variety of complex fluids, polymers and soft materials and is particularly effective for dense, high molecular weight, self-assembling polymer systems. The proposed research aims to make fundamental breakthroughs in the methodology for conducting simulations, which should enable up to two orders of magnitude acceleration in computational design of soft materials for emerging applications in microelectronics patterning, water purification, and energy and medical devices.

Broader impacts of the proposed research include a continuance of the PIs' strong record in graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under the proposed project will be further leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.




Technical Summary

This project will build on recent developments by the PIs and co-workers of the field-theoretic simulation method, enabling direct numerical investigations of field theory models of polymers and soft materials without resorting to the mean-field approximation. The proposed research aims to make fundamental, transformative breakthroughs in understanding and methodology by challenging current approaches to the "sign problem" associated with complex-valued models. The PIs' approach will enable studies of entirely new classes of polymers and soft materials and applications to emerging polymer technologies. Specific components of the project include:
1. Complex to real mapping methods. Methods will be developed for systematic mapping of (d+1)-dimensional complex-valued microscopic polymer field theory models to d-dimensional real-valued, density explicit models. Such a methodology will enable highly efficient simulations of diverse families of nano-structured polymers on unprecedented length scales.
2. Hybrid Monte Carlo -Complex Langevin methods. The PIs will utilize a new "basis function free" approach inspired by hybrid quantum-classical treatments of hard condensed matter. This technique will offer improved stability and enable a diverse set of sampling options, e.g. force-bias Monte Carlo method and flat histogram methods.
3. Applications to challenging polymer morphology problems. The new field-theoretic simulation methods developed in this program will be used to address difficult materials problems such as recently discovered "bricks-and-mortar" fluctuation-stabilized phases in mikto-arm polymer alloys. The computational efficiency gains will be exploited in studies guiding directed self-assembly approaches to advanced lithography.

Broader impacts of the proposed research include a continuance of the PIs strong record in graduate and post-doctoral training in theoretical and computational polymer science. A particular focus will be to expose students and post-docs with classical physics training to broader soft materials/polymer science disciplines through a close coupling with experimental groups at UCSB in chemical engineering, materials, and chemistry. The fundamental understanding gained under the proposed project will be further leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercial polymer and complex fluid formulations.

1510333(Leal)

It has been found that during the processing of complex fluids, such as polymer and surfactant solutions, liquid crystals, etc., large molecules in the solution can migrate to more concentrated areas. The goal of the proposed research is to understand this phenomenon, known as shear-induced banding, for the case of polymers. Discovering the fundamental reasons for this phenomenon has significant technological implications in processing and manufacturing of complex fluids that are common in the petrochemical, consumer products and the food industry.

When a macromolecular suspension (e.g., surfactants, polymers, and possibly proteins) is sheared, there is what is known as stress-induced migration of the macromolecules or micelles toward regions of higher concentration of the solution, via the so-called Helfand Fredrickson (HF) mechanism. In this work, the co-PIs propose to explore whether this mechanism can produce macroscopic concentration gradients in polymer solutions - a case where this phenomenon is somewhat controversial. The co-PIs, through prior theoretical work, have suggested that the coupling between the polymer stress and concentration in entangled solutions produces a linear instability for simple shear flow, and this instability leads to shear banding. In this proposal, they propose a coordinated experimental and computational approach to investigate this problem, and then to generalize the results to other flows: (a) pressure driven flow in a tube which exhibits a "spurt" instability, and (b) flow in 2- and 4-roll milling flows, i.e., testing their models under different stress patterns and even extensional flows. The proposed approach will involve both careful experiments (using rheo-NMR and neutron scattering) and computations. Outreach and dissemination of research is planned, involving graduate students in research. In addition, results will be disseminated to the industry.

This project, acquiring a computer cluster (mini-supercomputer) to replace the old one, aims to serve the computational needs facilitating scientific research and education in multiple areas. The machine includes 120 node Infiniband interconnected cluster for efficient message passing interface (MPI) parallel processing, four shared memory "fat nodes" with 1 Terabyte (TB) of memory/node, four graphic processing unit (GPU) nodes built around NVIDIA Tesla P100 1 Gigabyte (GB) GPUs, and four Intel Knight's Landing nodes. This blended system will serve the computational needs of the vast majority of campus researchers. This system will also service users needing large-scale resources by allowing development, prototyping, and benchmarking calculations locally, prior to production runs at supercomputer centers.

The research enabled spans multiple departments and supports research in many campus centers including AlloSphere Research Facility, the California Nanosystems Institute, the Center of Polymers and Organic Solids, the Earth Research Institute, the Kavli Institute of Theoretical Physics, the Marine Science Institute, the Materials Research Laboratory, and the National Center for Ecological Analysis and Synthesis. This interdisciplinary and mainly collaborative research will be facilitated by the presence of an available local facility, without the administrative hurdles and delays associated with application to supercomputing centers.

Broader Impacts:
The cluster is expected to play a prominent role in educating the next generation of scientists, engineers, and mathematicians. The NSF Integrated Graduate Education and Research Traineeship (IGERT) program in Network Science and Big Data will also employ the cluster that will additionally be utilized by undergraduates, high school, and community college students and K-12 teachers via existing sponsored programs. It will also contribute to attract others students and researchers. Furthermore the facility will service graduate participants in the University of California Leadership Excellence through Advanced Degrees (UCLEADS) and the Bridges to Doctorate programs. These programs help increase the number of under-represented students involved.

Non-technical Description: Block polymers are macromolecules that contain segments or 'blocks' of repeated polymerized monomers of at least two types. Much as proteins have tremendous variation in property and function in biological systems by virtue of the choice and placement of amino acid residues along the polymer backbone, the properties of block polymers can be widely tuned by varying the length, placement, and chemical identity of their constituent blocks. Block polymers are the basis for many important types of soft materials such as elastomers and adhesives, but are increasingly important in applications such as advanced membranes for batteries and fuel cells, medical devices, and soft templates for patterning microelectronic devices. A current challenge in deploying block polymers in such applications is that the chemical design space is vast and there is very limited data and predictive ability connecting the chemical structure to the derivative properties in a given material. This project aims to dramatically accelerate block polymer materials discovery by closely coupling modern theory and simulation approaches with state-of-the-art synthesis and characterization. Through extensive experimental feedback to validate and continuously improve models and simulation methods, the project will build the foundations for a future in which in silico design of block polymers is routine.

Technical Description: Block polymers are attractive for creating advanced materials with novel functionality by embedding multiple physical or chemical properties within a single compound. Such polymers are also attractive for manufacturing as their synthesis is scalable and they embed nanostructures spontaneously by thermodynamic driving forces arising from the incompatibility of the different blocks. However, as the demand for distinct desirable properties exhibited by a single material increases, so must the number of blocks. The corresponding design space increases geometrically with the number of blocks and block chemistries, making an intuition-based, trial-and-error approach infeasible. Instead, the project adopts a computationally-driven materials discovery approach, building on recent game-changing advances in self-consistent field theory and global optimization strategies for materials design and discovery. These computational strategies are coupled to an ambitious, advanced synthesis and characterization program capable of realizing the desired materials in practice. Through experimental feedback to validate and continuously improve models and simulation methods, the project will build the foundations for a future in which in silico design of block polymers is routine.

NONTECHNICAL SUMMARY
This award supports theory and computation, and education to advance computer simulation of polymeric materials which are based on polymers, long-chain-like molecules. Polymers are versatile materials that have remarkably broad applications in textiles, plastics and rubbers, paints and coatings, and consumer products including haircare products, cleansers, detergents, etc. They are also increasingly important in new energy harvesting technologies such as organic solar cells, as solid electrolytes in energy storage devices such as batteries, and in advanced drug delivery and medical devices. Perhaps surprisingly, the design of new polymers for such applications proceeds by trial-and-error experimentation until the molecular design yields the targeted properties and function.

This project aims to advance in-silico computational design of polymeric materials. One component of the project will develop a new theoretical representation of polymers into a computational platform that will enable the design of materials with thermally reversible bonds. Such materials have unique properties such as self-repair when damaged, or responsiveness to thermal or chemical stimuli, both important in a variety of emerging applications. A second effort aims to link molecular simulations at the atomic scale with simulations that employ a different theoretical formulation and can reach scales of hundreds of micrometers. This capability will enable chemical details to be embedded in the theoretical models; the latter providing the link to polymer material properties. If successful, this multiple length scale modeling platform could dramatically accelerate the design of polymers for existing and new applications.

Broader impacts of the proposed research include engagement by the project personnel in graduate, undergraduate, and post-doctoral training in theoretical and computational polymer science. Theoretically-oriented students will be exposed to broader soft materials disciplines through a close coupling with experimental groups at the University of California, Santa Barbara (UCSB) in chemical engineering, materials, and chemistry. Knowledge gained under the proposed project will be leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercially relevant polymer formulations. All participants will contribute to the vibrant education and outreach programs of UCSB's Materials Research Science and Engineering Center.


TECHNICAL SUMMARY
This award supports theory and computation, and education to advance theory and modeling of polymeric materials. This project will enhance the capabilities of the field-theoretic simulation (FTS) method, permitting numerical investigations of field theory models of polymers and soft materials without resorting to a mean-field approximation. One project component builds a new platform for FTS based on coherent-states polymer field theory, a long-neglected representation of interacting polymers inspired by quantum field theory. The proposed work aims to develop and optimize algorithms for simulations of coherent states models and apply those algorithms to fundamental studies of reversibly bonding, supramolecular polymers. Relationships will be explored between variables such as bonding equilibrium constants, stoichiometry and polymer architecture, and self-assembly behavior and thermodynamic properties. The unique structure of the coherent-states framework will enable a new force-matching scheme for systematic coarse-graining within FTS, applicable to both supramolecular and non-reactive polymer systems. Another component of the proposed research is to develop a workflow in which all-atom particle models are mapped to coarse-grained particle models using relative entropy minimization; the latter models of a form to allow analytical conversion to a fully-parameterized field theory. FTS can then be used to access mesoscale structure and thermodynamic properties directly connected to the underlying chemistry of the polymers.

Broader impacts of the proposed research include engagement by the project personnel in graduate, undergraduate, and post-doctoral training in theoretical and computational polymer science. Theoretically-oriented students will be exposed to broader soft materials disciplines through a close coupling with experimental groups at the University of California, Santa Barbara (UCSB) in chemical engineering, materials, and chemistry. Knowledge gained under the proposed project will be leveraged through the Complex Fluids Design Consortium at UCSB, an industry-national lab-academic partnership that is addressing the computational design of commercially relevant polymer formulations. The all-atom to FTS workflow targeted by the project has the potential to revolutionize in silico design of such formulations. All participants will contribute to the vibrant education and outreach programs of UCSB's Materials Research Science and Engineering Center.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.