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NanotechnologyNanoscience Modeling and Simulation Develop models of nanomaterials processing and predict bulk properties of materials that contain nanomaterials.

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Presentation on theme: "NanotechnologyNanoscience Modeling and Simulation Develop models of nanomaterials processing and predict bulk properties of materials that contain nanomaterials."— Presentation transcript:

1 NanotechnologyNanoscience Modeling and Simulation Develop models of nanomaterials processing and predict bulk properties of materials that contain nanomaterials Bridge models between scales, from atoms to self-assembly to devices Manufacturing & Processing Develop unit operations and robust scale-up and scale-down methodologies for manufacturing Synthesis Separation Purification Stabilization Assembly Characterization tools Develop real-time tools for measuring and characterizing nanomaterials, particularly online and in-process Synthesis and Assembly Develop new paradigms to create nanoscale building blocks Develop approaches for controlled assembly of nanocomposites and nanostructures Priority R&D Needs for Nanotechnology Commercialization Characterization tools Develop analytical tools for measuring and characterizing nanomaterials Chemical Industry Application Areas Catalysts, coatings, ceramics, sorbents, membranes

2 Joint nano-Metrology Needs 1.Large volume nanotube characterization of electronic properties Bandgap distribution Could be useful for characterizing other nanoparticles On wafers or as grown 2.In line particle characterization (1-50nm) Particle size distribution Particle surface morphology distribution

3 Large Volume Electronic Property Characterization Currently no single tool that can characterize bandgap distributions of large numbers of nanotubes. Fluorescence appears to be the most likely characterization tool, but research is needed: –Fluorescence cross sections of CNTs vs diameter & chirality & bandgap in different chemical environments –Need to characterize interactions that can cause quenching (Bundles, SiO2, High K, chemicals) –Identify conditions where fluorescence could be applicable Novel concepts for canceling quenching??

4 In situ Nano-particle (sub 50nm) Monitor Current techniques are not currently compatible with in situ monitor applications –Small angle X-ray scattering Measure particle size distribution and surface area Compatibility with flow cell demonstrated –Brownian motion techniques Sensitive to flow, so not compatible with in situ application –TEM Holography Particle size & surface morphology in development or excursions, limited statistics Not compatible with in situ –Particle mass spec: Proposal Particle weight, composition & surface chemistry Valuable in development & excursions, not in situ –MEMs Particle detectors: TBD

5 Real-Time Characterization In addition to ongoing efforts in development of advanced characterization tools for R&D, there is a need to develop deployable process-monitoring tools that can be used to ensure nanomaterial and nanoproduct consistency on a manufacturing scale. Such instruments would include real-time, on-line characterization tools and rapid quality control (QC) tests for samples. Needs include monitoring the following: in situ particle size and shape in situ composition or function (including charge; surface energy; functionalization; magnetic, electrical, or optical properties, etc.) surface chemistry at nanoscale, including fractional coverage and thickness of coatings on nanoparticles quality of particle dispersion in a solid phase

6 Large-Volume Electronic Property: Work in large-volume electronic property characterization is needed because there is currently no single tool that can characterize bandgap distributions of large numbers of carbon nanotubes. Fluorescence appears to be the most useful potential characterization tool as it may yield information on cross-sections of carbon nanotubes (CNT) vs. diameter, chirality and bandgap in different chemical environments. However, more research is needed to identify applicable conditions. Quenching of fluorescence from conditions such as the presence of bundles, SiO2 or other chemicals and high dielectric constant (K) could limit the applicability of this technique and will require new concepts to cancel the quenching. In Situ Monitoring: Current analytical techniques for nano-particles cannot yet be used for in situ monitoring. Small angle X-ray scattering can measure particle size distribution and surface areas, and has demonstrated compatibility with flow cells. Micro-electro-mechanical systems (MEMS) based particle detectors may prove useful. A proposed particle mass spectrometer to characterize particle weight, composition and surface could be valuable in development and excursions, but not for in situ applications. Brownian motion techniques are sensitive to flow, and so will not be useful for in situ applications. TEM holography has been used to study particle size and surface morphology in development or excursion, but is also not compatible with in situ monitoring.

7 Utility of various research tools in nanomaterial property characterization Nanomaterial Properties Research Tool Application Small Angle X-ray scattering Mass Spectroscopy Microscopy (SEM/TEM) Particle sizeYes Yes (1000 particles/sec) Yes (5000/hour SEM, TEM ?) Particle size distributionYes Bulk compositionNo Yes (photo ionization of sample) No Surface compositionNo?Yes Surface composition-ligandsNo?? Particle structure (Architecture) ?? Aberration Corrected TEM carbon sensitivity? Level of dispersion/aggregationYes?Yes (if in matrix) Particle shape? Yes, with ion mobility measurement Yes Particle aspect ratio?NoYes Surface chargeNo??? Surface functionalityNo??Yes? Homogeneity/Heterogeneity (surface, size, composition) ?No Yes (dependent on statistics) Heterogeneity of population??Depends on statistics Heterogeneity of single particle??Yes ? indicates utility still to be determined based on input from other experts

8 Magneto-electronic and transport properties The experimental capabilities essential for further understanding these properties of nanostructures include: Statistical measurement of the electronic transport properties of nanostructures Correlation of electronic transport properties with atomistic structure in the nanostructure Measurement of the properties of contacts to nanostructures, and correlation with atomic structure of nanostructure/metal interface Measurement of the optical properties of nanostructures and of opto-electronic processes Measurement of the temperature dependence of nanotube bandgaps, addressing the role of phonons Effect of adsorbates on nanowire conductivity Large-volume electronic properties

9 Nano-mechanical and interface properties: Measurement of the three-dimensional mechanical response of nanostructures to controlled applied strain Measurement of the mechanical response of nanostructures to electronic, magnetic, optical, and thermal stimulation Atomic imaging of defects, failure modes, dislocations, grain boundaries, interfaces, and similar properties Effect of substrate interactions on nanostructure deformations

10 Thermal properties Characterization of phonon dispersion in nanomaterials and interfaces Measurement of thermal transport in nanostructures, including role of interfaces Temperature dependence of thermal properties


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