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| Keynote Address |
| 12/16/2002 - 8:30am |
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Session Audio
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| Speakers:
• Phaedon Avouris, Ph.D.
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| Session I: Materials |
| 12/16/2002 - 9:30am |
In this session, Anna Balazs, Ph.D., will discuss:
The development of novel biomimetic, photonic and electronic materials depends on the manipulation of both organic and inorganic components on the nanometer length scale. The most efficient route for creating such complex composites is through self-assembly, where cooperative effects among the different components drive the system to form nanostructured materials. The aim of our research is to use theory and simulation to isolate new routes for driving nanoparticles and block copolymers to self-assemble into spatially organized systems. The morphology of such composites will depend not only on the characteristics of the copolymers, but also on the features of the nanoparticles. To explore this vast parameter space and predict the mesophases of the hybrids, we have developed a mean field theory for mixtures of soft, flexible chains and hard spheres. Applied to diblock-nanoparticle mixtures, the theory predicts ordered phases where particles and diblocks self-assemble into periodic structures. The method can be applied to other copolymer-particle mixtures and can be used to design novel composite architectures.
Hong Koo Kim, Ph.D., will discuss:
Self-assembly is considered a promising approach that may overcome the limitations of conventional lithography. Self-assembled nanostructures, however, usually show a limited domain size (typically a micron or less), and achieving orders of scales, i.e., from nano to chip/wafer scale, have remained a major challenge. I will discuss a new approach for forming single-domain, ordered nanopore arrays with controlled symmetry on the macroscale area (chip or wafer scale) of foreign substrates. The method involves holographic patterning of wafers in order to guide/direct the self-organization phenomenon in an anodic oxidation process. This "directed self-assembly" offers a cost-effective (high-throughput and low-cost) alternative to the existing nanofabrication techniques, which mostly rely on the low-throughput serial patterning process. The ordered nanopore arrays can be used as a host or template for a variety of nanodevices, such as separation and absorbent media, catalytic surfaces and supports, gas storage media for fuel cells and batteries, photonic crystals, etc. When filled with functional materials (such as metal, semiconductor, magnetic, ferroelectric, optoelectronic, and bio/chemical materials), the pores can form ultra-high density arrays of logic gates, memories, sensors and transducers. I will summarize the prospects and challenges of developing nano-systems on a chip based on the ordered nanochannel arrays.
Xinjuan (Scott) Mao, Ph.D., will discuss:
The main objective of this project is to investigate deformation and strengthening mechanisms in modulated, nanolayered structures and thin film using conventional nanoindentation and in-situ nanoindentation transmission electron microscopy (TEM) techniques. Nanolayered composites (NLCs), e.g., metal/ceramic and ceramic/ceramic NLCs, typically consist of hundreds of thin layers of materials that enhance the mechanical properties (hardness and wear-resistance) of these systems. They are very attractive as ultra-hard coatings in tribological applications and have garnered significant attention from both the scientific and industrial communities. To develop a better and ideally quantitative understanding of these macroscopically observed phenomena (enhanced hardness and wear resistance) and their relationship with the high density of interfaces in NLCs, it is necessary to observe indentation at the nanoscale and in real time. We propose to conduct conventional nanoindentation and unique in-situ nanoindentation TEM experiments so that we can observe the effects of local nanostructure (interface, crystal structure, and lattice strain) on deformation and fracture processes. |
Session Audio
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| Speakers:
• Anna Balazs, Ph.D.
• Hong Koo Kim, Ph.D.
• Scott Mao, Ph.D.
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Click below to view:
• kim_hong_koo.pdf 5.2 MB
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| Session II: Materials |
| 12/16/2002 - 10:45am |
In this session, Sandy Asher, Ph.D., will discuss:
We utilize a hierarchical assembly process to create crystalline colloidal arrays of nanoscale and mesoscale colloidal particles. Monodispersed particles and composites of particles are synthesized and are combined with hydrogel matrices to form materials with nanoscale periodicities. These materials diffract light from an embedded array of particles. The transmission and diffraction properties can be controlled by photons, magnetic fields, and binding of particular chemical species. These smart materials act as optical switches, optical memories, and chemical sensing materials.
Gilbert Walker, Ph.D., will discuss:
A challenge in nanoscience remains the chemical characterization of nanoscaled materials under ambient conditions. To meet this challenge, we are developing infrared near field microscopes. These tools reveal the distribution of chemical functional groups in a sample on a sub-100 nanometer length scale. Our new understanding of nanooptics is also enabling for other nanotechnologies. We have developed new methods to prepare nanostructures of polymers, carbon nanotubes, and metals for information storage, biomaterials, and molecular electronics.
John Yates, Jr., Ph.D., will discuss:
Understanding the surface chemistry of single-walled carbon nanotubes is an extremely interesting and challenging scientific goal. Tailor-making nanotubes to have specific adsorption properties could be of extreme importance in fields such as environmental cleanup, sensor technology, and nanoelectronics. Using modern surface science techniques, we have investigated the behavior of both natural and modified single-walled carbon nanotubes. The closed ends and walls of these tubes are opened by oxidative treatments, and infrared spectroscopy has been used to monitor the formation and subsequent decomposition of these oxidized groups. Removal of these blocking groups from the entry ports of the nanotubes produces ideal adsorption routes for delivering adsorbate molecules into the interior of the nanotubes. The physical adsorption of CF4 and Xe in the interior and on the outer walls of the nanotubes has been studied by both kinetic and infrared spectroscopic techniques. Adsorbed CF4 species exhibit characteristic infrared spectra in the interior and the exterior of the nanotubes, and methods have been found to preferentially deplete the internally-bound CF4 by displacement. These measurements probe the effect of confinement of molecules in pseudo one-dimensional space. |
Session Audio
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| Speakers:
• Sandy Asher, Ph.D.
• Gilbert Walker, Ph.D.
• John. Yates, Ph.D.
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Click below to view:
• walker_gilbert.pdf 942 KB
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| Luncheon |
| 12/16/2002 - 12:00pm |
| Remarks by Mark Modzelewski, Founder and Executive Director, NanoBusiness Alliance, with an introduction by James Maher, Ph.D., Provost, University of Pittsburgh. |
Session Audio
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| Speakers:
• James Maher, Ph.D.
• Mark Modzelewski
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| Session III: Computational |
| 12/16/2002 - 1:30pm |
In this session, Rob D. Coalson, Ph.D., will discuss:
Recent efforts to miniaturize electronic components have stimulated intensive study of the properties of electron transport through single molecules that are coupled to metallic leads. In the future these systems may be used as wires or logic elements (e.g., transistors and rectifiers) in molecular-level circuits. Theoretical analysis suggests that shining light of an appropriate frequency and intensity on a molecular wire can dramatically modify the electric current through the molecular junction compared to the "field-off" case. This raises the possibility of switching electron transport routes through molecular wires via an applied laser field.
Karl Johnson, Ph.D., will disucss:
Single-walled carbon nanotubes (SWNTs) are unique nanoporous materials that offer potential uses in gas adsorption and separation. The highly regular one-dimensional pore structure of SWNTs is appropriate for molecular sieving, whereby molecules are separated according to size/shape differences. We show that nanotubes can also be useful for separating isotopes of hydrogen based on differences in the quantum ground states of molecules adsorbed in nanotubes or the interstitial channels of nanotube bundles. Knowledge of the transport diffusivities of gases in carbon nanotubes is important for estimating their potential usefulness as membrane materials for gas separations. We have calculated the transport and self-diffusivities of hydrogen in SWNTs of different diameters and in two different zeolites. We have used equilibrium molecular dynamics coupled with grand canonical Monte Carlo simulations to compute the transport diffusivities of gases in nanotubes and zeolites. We demonstrate that diffusion of gases in carbon nanotubes is generally about three orders of magnitude faster than diffusion in common zeolites of similar pore size.
Kenneth D. Jordan, Ph.D., will discuss:
Scanning tunneling microscopy (STM) has developed into one of the most important tools for characterizing and manipulating surfaces on the nanoscale. This talk will describe our work on theoretical calculation of STM tunneling currents for hydrocarbons adsorbed on semiconductor interfaces and of simulations of the rearrangements of silicon surfaces following STM-induced hydrogen desorption from the Si(100) surface. |
Session Audio
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| Speakers:
• Rob Coalson, Ph.D.
• Karl Johnson, Ph.D.
• Ken Jordan, Ph.D.
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Click below to view:
• coalson_rob.pdf 865 KB
• johnson_karl.pdf 1.24 MB
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| Session IV: Biomedical |
| 12/16/2002 - 2:45pm |
In this session, Graham Hatfull, Ph.D., will discuss:
Bacteriophages are viruses of bacteria. They have no ability to reproduce autonomously but can replicate following infection of an appropriate bacterial host. Successful replication requires three main processes: generation of copies of the phage genome, synthesis of phage protein components, and assembly of all of the components into progeny viruses. These bacteriophages are of interest to nanotechnology because: 1) they are easy to propagate, 2) they are numerous and diverse, 3) complex structures are assembled from relatively few constituent proteins, 4) their assembly and their behavior involve highly dynamic processes. We are investigating three aspects of bacteriophages with potential for nanobiotechnological applications. First, we are manipulating the major capsid subunit proteins of mycobacteriophages to explore their utility in the molecular manipulation within complex self-assembled structures. Second, we are studying the use of phage tape-measure proteins as molecular railroads to move small protein segments from one location to another. Lastly, we are dissecting a phage-encoded site-specific recombination process that can function as an activatable switch between two defined states.
Roger Hendrix, Ph.D., will discuss:
Bacteriophages (bacterial viruses) have been perfecting their abilities as molecular nano-machines, through evolution, for the past 3.5 billion years. Every time a phage infects a bacterial cell, it has the opportunity to swap genes with other phages or otherwise mutate to create new genomes that can be submitted to the scrutiny of natural selection. We calculate that such an infection occurs about 1025 times per second on a global scale. Not surprisingly, phages have achieved a rather high level of engineering sophistication. We have studied the details of the remarkable coordinated ballet that the proteins of one particular phage go through on their way to assembling and maturing the virus "capsid", a protein structure that packages and protects the viral DNA and delivers it to the next host cell. In designing nano-devices for human benefit, we suggest that there is much to be gained by taking advantage of the evolutionary experience of the phages.
William Wagner, Ph.D., will discuss:
Biodegradable elastomers offer attractive mechanical properties for many applications in soft tissue engineering, where cells are grown into porous scaffolds (with mechanical stimulation) to generate functional tissues. While several types of biodegradable elastomers have been reported in the literature, there are fewer reports where these materials have been processed into scaffolds suitable for in vivo placement or for support of cellular adhesion and growth. The process of electrospinning, where an electric field overcomes surface tension to generate and draw nanoscale fibers, offers a means to create scaffolds with extracellular matrix-like morphologies that might retain mechanical strength and flexibility. This method also permits protein incorporation into spun fibers to impart bioactivity. Our objective in this study was to utilize electrospinning to construct biodegradable, elastomeric scaffolds from a poly(ester urethane)urea (PEUU) with or without added type I collagen. The coupling of electrospinning methodology with biodegradable elastomers and bioactive proteins may provide combinations of chemical, mechanical and biological properties attractive for many biodegradable biomaterial applications. |
Session Audio
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| Speakers:
• Graham Hatfull, Ph.D.
• Roger Hendrix, Ph.D.
• William Wagner, Ph.D.
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| Session V: Industry Perspectives |
| 12/16/2002 - 4:00pm |
| Roundtable discussion with an introduction by Gerald Gruber, Ph.D., Vice President for Science and Technology, PPG Industries. |
Session Audio
• NOT AVAILABLE
| Speakers:
• Gerald Gruber, Ph.D.
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