Tomasz Kowalewski - US grants

9871874
Ruoff
This award provides partial support for an effort addressing the manipulation of matter on the nanoscale to form functional nanostructures. New methods and tools will be developed and used to: (i) study a new type of mechanochemistry were carbon nanotubes are mechanically strained to create very specific atom locations for chemical reaction (nanostressing stage); (ii) controllably shape surfaces, manipulate nanotubes and build structures with the AFM probe used in a new, unconventional way; (iii) dispense gas and liquid molecules (the latter in volumes down to 100 nm3) with sub-nm positional control (nanotube pipet); (iv) achieve spatiotemporal control over a new class of charged or magnetic particles using finely controlled electric fields or magnetic field gradients (designer particles).

Development of new tools and methods for nanoscale manipulation will be centered around carbon nanotubes (NT). Unique features of NT's as potential building blocks for nanotechnology include: unique size; the presence of a hollow core; unusual mechanical properties; possibilities for mechanically activated chemistry. Tools and methods which will be developed in this study will be essential for achieving one of the long term objectives of the proposed effort - turning NT's into components in functional nanostructures and as tools for building functional nanostructures.

A piezoelectric nanostressing stage will be built and used to apply mechanical stress to NT's and mechanically activate chemical reactions by straining carbon-carbon bonds. Site-specificity of such mechanically sensitized reactions, which are expected to occur in kinked regions of nanotubes, is very desirable for potential applications of NT's in nanotechnology. The nanostressing stage will also be used to elucidate the mechanical behavior of various types of NT's and of very thin graphite sheets (potentially as thin as a single atomic layer).

Tapping mode AFM, which was originally developed to minimize the interactions between the probe and the surface, will be used in a new and unconventional way to manipulate (objects on) surfaces and then image them with high resolution. Operations such as micromachining, nanohammering, and pushing objects on surfaces will be achieved by controlled increase of tip-surface interactions. High-resolution imaging after manipulation will be possible owing to our recent discovery that AFM probes can be resharpened by mechanical deposition of metal grains at the tip. New AFM methods and tools developed at Washington University and also at Zyvex will be applied to manipulation of NT's on surfaces (both at ambient conditions and under liquids) and to study the new mechanochemistry of NT's.

A nanotube pipet, capable of delivering volumes of liquids as small as several tens to a hundred nm3 (note that 1 femtoliter of water is 1 cubic micron, and that 100 nm3 contains 3000 molecules of H2O) will be built and used for fundamental studies of living cells and to construct nanostructures on surfaces. It will be capable of delivering gases, such as organometallics, which could be pyrolyzed on a surface as a means of writing nanoscale metal features, and of delivering very small volumes of biomolecules to cells.
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This Nanoscale Interdisciplinary Research Team (NIRT) project, co-funded by the National Science Foundation Divisions of Materials Research, Chemistry, and Chemical and Transport Systems, will develop synthetic strategies and characterization protocols for the production and study of one-, two- and three-dimensional superstructures composed of stabilized nanoparticle assemblies. The synthetic approach involves the systematic ordering, in solution and on substrates, of crosslinked assemblies of copolymers, as robust core-shell building blocks, to manufacture 1-dimensional meso-scale (~100 nm to ~1 mm), 2-dimensional micro-scale (~1 mm to ~100 mm) and 3-dimensional macro-scale (>100 mm) objects, each comprised of nanoscopic building blocks. The result will be the creation of entirely unique composite morphologies that are not accessible in the phase diagrams of the copolymers directly. This strategy mimics the control of chemistry at the nanometer scale that is currently the exclusive province of living systems. Utilization of the nanoscale organic-based superstructures as scaffolds for the initiation of nanocrystalline growth of inorganic materials and biomacromolecules will be a key goal of the investigation. The mechanisms by which the organic superstructures promote crystallization and co-crystallization will be studied in detail. The hypotheses to be tested include: (1) organic nanoparticles will be assembled into well defined one-, two- and three-dimensional superstructures, suitable for fabrication into useful device applications; (2) such superstructures will present interfacial contacts that template the crystallization events to produce unique and controllable nanocrystalline phases, initiated from a surface or via co-crystallization; (3) the nature of the organic superstructures and the nanocrystalline materials will result in unique physical, optical, magnetic, and mechanical properties.
The educational and research aspects of the proposed activities will cross several disciplines (organic chemistry, biology, physical chemistry, polymer physics, chemical and mechanical engineering, and materials science) to address effectively the study of one-, two-, and three-dimensional superstructures, composed of two or more nanoscale constructs, and of templated inorganic/organic nanocrystalline materials. The proposed research is rich with opportunities to impact education. Students will benefit through interdisciplinary, multi-site research activities. An outreach course developed (Fall 2001) at Washington University for K-8 teachers will be enhanced and implemented at the participating institutions. The focus of this NIRT also creates an effective platform for societal education of the benefits of nanoscience and nanotechnology. For example, the proposed nanostructured solids may represent new advanced materials for medicine, such as "smart" hydrogel-like coatings for controlled release of drugs, and scaffolds for tissue engineering. These materials may also be the next generation of advanced separation media, tough optically clear solids, catalysts or nanocomposites used in the fabrication of nano- or micro-mechanical devices. Thermally-responsive memory devices and complex nanoscopic coatings for cantilever-based sensor devices are particular applications that will be investigated for the 1-, 2-, and 3-dimensional superstructures. Additionally, the proposed materials will be evaluated as nanoscopic surfaces from which the crystallization of inorganic salts or biomacromolecules can initiate. The controlled co-crystallization of the superstructures will be investigated, as a model system for the nanocrystalline phases found in bone growth.

This Nanoscale Interdisciplinary Team (NIRT), co-funded by the Divisions of Materials Research (DMR) and Electrical and Communications Systems (ECS) will use a combination of macromolecular engineering, self-assembly and solid state chemistry to develop a new generation of well-defined nanostructured carbons for electronics. This approach is based on controlled pyrolysis of self-organizing condensed phase precursors, such as well-defined block copolymers containing polyacrylonitrile, prepared using controlled radical polymerization techniques. The carbon materials, as a consequence of the self-organized nanoscale morphology of the block copolymer precursors, will exhibit a wide range of well-defined nanostructures of different dimensionalities (dots, filaments, lamellae, and complex three-dimensional architectures). The team will undertake a concentrated, systematic, interdisciplinary effort to map the phase diagrams of the block copolymer precursors and resulting nanostructured carbons, and determine the relationship between the molecular compositions and processing conditions and the resulting nanostructure and electronic properties. Particular emphasis will be given on the establishment of the relationship between the pyrolysis conditions and the resulting carbon nanostructures, and their electronic properties.
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Novel nanostructured carbon materials obtained through this effort could potentially find a wide range of electronic device applications ranging from field emission flat panel displays to sensors and actuators, as well as, environmentally friendly devices for energy conversion (photovoltaic cells) and energy storage (supercapacitors). The team will develop prototypes for some of the most promising of these applications and will identify the nanostructures/properties most desirable for each.. The proposed synthetic methods are potentially scalable for use in commodity, engineering carbons. Thus it is anticipated that the research results may provide a basis for practical large-scale technologies. The team has ties to industry, through the Atom Transfer Polymerization/Controlled Radical Polymerization Consortium housed at Carnegie Mellon. Strong industrial participation in this consortium will facilitate transfer of information and technology generated by the proposed activities and will provide a starting point for industrial partnerships. The broader educational impacts of the team's efforts will include training graduate and undergraduate students and postdoctoral fellows in a highly interdisciplinary environment. The members of the team will also participate in Carnegie Mellon's Science-Van K-12 outreach program, developing units aimed at acquainting students with nanoscience and nanotechnology.
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CTS-0521079-MRI Walker Carnegie Mellon University

Acquisition of SAXS for Nanostructural Characterization of Self-Assembled Materials

This project provides funds to purchase a laboratory small-angle x-ray scattering (SAXS) device to be used as a shared "facility." Initially, the facility will be used by nine research groups representing 6 departments in 2 colleges at Carnegie Mellon University (CMU). The theme that connects all of the projects is the development of technologies and applications based on self-assembled nano-structured materials. While the types of materials and applications vary significantly, the common need is for direct in situ quantification of nano-scale structure. The proposed SAXS device meets the needs of the group, as it is a modular, robust instrument with relatively low maintenance requirements. A laboratory is available to house the proposed device, and four of the senior investigators have developed a plan to oversee the regular maintenance, scheduling and use of the facility. A significant need for accessible, in-house SAXS has developed in several departments at CMU. The SAXS facility at CMU will attract more researchers, nucleating a group of graduate students, post-docs and faculty trained in the analytical techniques necessary for characterization of nano-scale structure, particularly in self-assembled systems.

Intellectual Merit: Research in self-assembled nanostructured materials and applications was currently hindered at CMU by a lack of appropriate structural characterization equipment. The potential for initiation of new projects and ideas is not being recognized without a central facility for characterization and training. An accessible SAXS device facilitates existing research and nucleates new collaborations and projects. Currently, there is a core group of faculty and projects focused on utilizing self-assembly in block copolymers to control nano-scale structure in both organic and inorganic materials. Because of the expertise available and interdisciplinary environment at CMU, these projects span the synthesis, complete characterization and device development of technologies based on assembled block copolymers. Ongoing projects involve development of sensor technology based on conductive polymers, 3D-structured organic-inorganic nano-composites and novel processing paradigms for nano-structured thin films, among others. Associated with this core group are a number of projects covering a broader range of materials with a similar need for nano-scale characterization. These projects include the control (through synthesis) of self assembly of bio-macro-molecules for DNA separation and tissue engineering applications as well as the control of nano-particle assembly in confined geometries for microfluidic applications and formation of 2D Nano-particle arrays.

Broader Impact: Accessibility of this equipment will allow for training of engineers and scientists in the use of SAXS for nano-structural characterization. This direct exposure will impact graduate students, postdoctoral and undergraduate researchers at CMU. Industrial researchers will be involved through an existing short course, research consortia and collaborations with faculty members. The increased interactions between different research groups involved with the facility will provide the opportunity for developing modules to teach the basic ideas of molecular self-assembly and nano-technology to a wide variety of age groups. Currently, none of the highly successful outreach programs at CMU involve programs discussing nano-scale phenomena or nano-technology. Senior investigators on this proposal are already involved in these outreach programs, a central SAXS facility will allow for the interactions necessary to develop simple, yet explanatory tools for dissemination through various outreach programs at CMU

The objective of this research is to demonstrate a new magnetic recording paradigm using current-induced switching, which combines the advantages of patterned media, and the potential for lower manufacturing costs. This will be the first demonstration of single grain recording, and the smallest nanostructures yet investigated for current-induced switching. The approach will use self-assembled nanoparticle arrays as etch masks for patterning thin film multilayers into arrays of single particle bits. A conducting atomic force microscope probe will be used in contact mode to electrically contact individual bits. Low current densities will be used to sense the state of the bit, while high current densities will be used for switching. The noise power spectrum as a function of the applied current will reveal how effectively the spin torque is transferred. Simulations will be used to clarify the underlying physics.

This project will have broader impact in several areas. Two graduate students and several undergraduates will learn state-of-the-art techniques of nanoscale synthesis and fabrication, the use of scanning probe and electron microscopy for nanoscale structural characterization, and high sensitivity nanoscale transport measurement techniques. New science fair projects will be developed and the research of students in the Carnegie Mellon University/Milliones and Reizenstein Middle Schools Physics Concepts program will be supervised. Progress made in scanning probe-based recording, current-induced switching media, and the use of self-assembled structures for low cost, manufacturable nanopatterning will be significant for the magnetic recording industry.

This Nanotechnology Undergraduate Education (NUE) in Engineering program entitled "Interdisciplinary Undergraduate Program in Nanotechnology (IUPN)", at Carnegie Mellon University (CMU) is under the direction of Dr. Michael Bockstaller, Center for Nano-Enabled Device and Energy Technologies, in collaboration with faculty from the departments of Physics, Chemistry, Materials Science and Engineering, Electrical and Computer Engineering, Civil and Environmental Engineering and Philosophy. The primary goal of IUPN is to establish an integrated training program for undergraduate students in nanotechnology building on four existing courses and innovative mini-courses that will attract and engage talented students from multiple departments to the study of nanoscience and engineering. The proposed program will deliver a model for future undergraduate education in nanotechnology in which the focus is on the relevance of the connections among the traditional disciplines and a holistic view of 'sustainable nanotechnology' by integrating ethical and social science into the nanotechnology curriculum.

Research and development of organic semiconductors for electronic applications have shown intense growth in the last few years. Versatile attributes, such as solution processability and low cost, render these materials particularly attractive for applications such as electronic displays on flexible substrates, organic field effect transistors (OFETs) and large-area photovoltaics. However, carrier mobilities in organic semiconductors are much lower than their inorganic homologues. Evidence now indicates that carrier mobility in these systems depends on molecular structure and organization.

Intellectual merit: Our objective is to achieve better understanding of structural ordering effects on carrier mobility in polymer-based electronic devices. We propose to focus on optimizing the performance of OFETs based on polymers using novel synthesis and processing techniques that will achieve both amorphous and highly crystalline polymer morphologies. Our approach will include correlations of materials structural changes and device architecture with device performance. While the device applications will be focused on OFETs, the conclusions will pertain to a wide range of conducting polymer technologies.

Broader impacts: It is the aim in this project to train two graduate students and three undergraduate researchers in the area of structure-property-performance relationships needed for breakthrough technologies in electronic polymer-based devices. The students will have opportunities to interact with Plextronics, a local company and a technology leader in commercialization of organic light-emitting diodes and photovoltaics. The investigators will also collaborate with teachers in the Pittsburgh Public Schools (~60% minority students) on projects to experiment with conducting polymers.

Professors Kevin Noonan and Tomasz Kowalewski of Carnegie-Mellon University are supported by the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry to design and prepare new charged polymers that function as ion-exchange membranes. These membranes are sandwiched between the negative and positive compartments of fuel cells and are considered a key component of these energy conversion devices. A variety of consumer related products rely on fuel cells for clean energy generation. New cationic (positively charged) polymer membranes are synthesized using appropriate controlled polymerization techniques. Their chemical, electrochemical, and mechanical stability are assessed under fuel cell operating conditions. One of the main objectives of this work is to make durable membranes which can withstand the harsh chemical environments of a fuel cell device. If successful, fuel cells with these newly synthesized polymer membranes will not rely on precious metals for energy generation, which represents a significant economic advantage. Students from diverse backgrounds are trained and involved in this project. A "Fuel Cell Project" with educational material and demonstrations is being developed. The project is made available on the web and used to educate junior high school students about renewable energy life cycles.

In this project, the PIs are exploring the chemical and electrochemical stability of cationic polymers in the presence of hydroxide ions. The information obtained is used to build robust membranes for ion-transport in fuel cells. While transport of protons under acidic conditions is well established, hydroxide transport in solid polymer electrolytes under thermal and electrochemical stress is still a significant challenge. The development of next-generation robust, long-lasting and inert cationic materials for shuttling these caustic anions requires a combination of synthesis and characterization. Controlled polymerization techniques are critical for building the polymer materials. A battery of characterization techniques is used to evaluate their structure, stability and morphology. Specifically, X-ray scattering, atomic force microscopy, transport/device measurements and computational chemistry are used to probe the properties of these membranes. Transport and mechanical properties are tailored by synthesizing well-defined polymers and block copolymers. These materials are used to establish relationships between ion transport and morphology of novel ionomers. This work provides the basis for subsequent material design to optimize anion transport. If successful, the project will result in stable and efficient anion exchange membranes (AEMs) for alkaline fuel cells that do not need precious metals for proper function.

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.

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the NSF Division of Chemistry, Drs. Kevin Noonan and Tomasz Kowalewski of Carnegie Mellon University aim to develop and explore a new class of cyclic (or ring-like) organic molecules comprised of smaller rings (“rings of rings”). Generally, the path to making cyclic molecules involves bending linear molecules to join the ends together. As the size of the ring increases, it can be difficult to make the “ends meet” resulting in lower yield of the desired structure. Noonan and Kowalewski recently discovered that short linear chains of small furan rings can be modified in such a way that they spontaneously bend into macrocyclic ring-like shapes. They will be exploring the extension of this method to different variants of small rings to tune the properties for different potential applications. In these cyclic structures, a portion of the electrons reside in so-called pi-bonds, which under certain conditions enables them to flow freely such that the material behaves as a metal or semiconductor rather than an insulator. As such, they belong to the family of “green” organic electronic materials that can be derived from biomass, with high promise for sustainable energy applications such as solar cells, displays, and catalysts for generation of fuels and chemicals. The interdisciplinary character of this work will lead to training of chemists with a unique skill set encompassing chemical synthesis, novel methods, and advanced computational tools facilitating precise, efficient, and environmentally friendly chemical synthesis. The PIs will also use social media and podcasts to raise public awareness on key scientific concepts of essential societal importance such as energy, sustainability, and health.

Drs. Noonan and Kowalewski and their research teams will use a combination of synthesis, computation, and characterization to build a library of furan macrocycles and map the interplay between their structure and properties. The key synthetic strategy will involve using structure-directing ester side groups to promote efficient cyclization and extend it to achieve precise control of supramolecular assembly of these molecules. Computation will play a particularly important role in the studies of self-assembly by allowing exploration of a wide range of candidate structures and scenarios. It will help in determining the nature of intra- and intermolecular organization of the resulting nanostructures. Mapping the molecular and supramolecular properties of these materials will be paralleled, and correlated, with the investigation of their behavior in redox, charge transport and ion-binding processes. In addition, work on conjugated macrocycles will advance fundamental understanding of aromaticity by addressing key questions about the impact of molecular structure and conjugation on aromatic stabilization energy.

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.

The development of cutting-edge nanostructured materials for applications like smart surfaces, batteries, and synthetic tissues requires highly interdisciplinary teams as well as tools that can characterize materials across scales. Advanced functional materials have the potential to drive advances in sensing (for uses such as environmental monitoring, disease diagnosis and advanced manufacturing), energy storage for enhanced energy sustainability and robotics (with applications ranging from providing support to amputees and stroke victims to disaster response). The behavior of materials that have nanostructural features from Angstroms to hundreds of nanometers in size must be measured under realistic conditions to characterize their structural properties during use. This Major Research Instrumentation (MRI) award will support the acquisition of a Small to Wide Angle X-ray Scattering (SAXS/WAXS) system at Carnegie Mellon University (CMU) to address these needs, enabling high-throughput studies at a variety of length scales and under a variety of stimulation conditions. By customizing the system to enable high-throughput and robotic control of experiments, this instrument will facilitate the broadening of participation in X-ray scattering research to users across science and engineering. Through an “Initiative for fully-automated high-throughput SAXS/WAXS” and annual meetings of the Western PA SAXS/WAXS Interest Group, this project will seed new collaborations that enable next-generation robotics applications and developing methodologies for machine learning-based discovery. Short courses and case studies in existing courses will support the integration of research and teaching, and outreach on SAXS/WAXS will target women and underrepresented groups. Ease of use, automation and remote operation capabilities will facilitate utilization at a national level.

The research enabled by this instrumentation seeks to link material function to structure from the atomic to micron scales. The SAXS/WAXS system will enable researchers to conduct in situ and in operando studies across these scales to address a variety of important fundamental knowledge gaps. Specific goals include the use of the instrument to develop research contributions in the following areas: (1) solution-dependent conformation and dynamics of responsive nucleic acid nanosystems, (2) understanding and mitigating the structural evolutions in lithium ion battery electrodes that eventually lead to damage and catastrophic battery failure, (3) linking structure to function for novel antibacterial peptides, (4) elucidating the interplay between ion clustering and molecular packing/morphology of polymer matrix in governing the efficient transport in ion-transport membranes, and (5) the development of novel copolymer-based architectures in which lock-and-key interactions facilitate self-healing properties.

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.