2007 NSTI Nanotechnology Conference and Trade Show - Nanotech 2007 - 10th Annual

Nanoparticles: Dry Synthesis and Applications

Sunday May 20, 2007, 8:00 am - 6:00 pm, Santa Clara, California

Summary

nano particulates We will start with the history of this fascinating technology from ink production in ancient China and Greece to the Bible printing by Gutemberg in Mainz and to the current manufacture of optical fibers, carbon blacks, filamentary nickel, pigments and fumed silica through valiant Edisonian research highlighting limitations and opportunities for synthesis of new functional materials. An overview of flame and hot-wall reactors for synthesis of metal, alloys, ceramics as well as their composites will be discussed. The fundamental physical and chemical phenomena that control these processes are summarized. Principles for designing these processes by combining fluid and particle dynamics are presented. Emphasis is placed on scalable flame reactors that dominate the value and volume of today’s manufacture of nanostructured materials. In particular, it is highlighted the versatile flame spray pyrolysis process for synthesis of catalysts (CeO2/ZrO2, Pt/Al2O3, TiO2/SiO2), ZnO quantum dots for UV-filters, mixed ceramics such as translucent and radio-opaque Ta2O5/SiO2 and others. Synthesis of solid nano- or hollow micro-particles of Bi2O3, CeO2 or Al2O3 by combustion spraying of solutions, emulsions or slurries will be shown along with process design criteria. Next, the course highlights specific cases for hot-wall synthesis of selected metals (Al, Bi, Pd and Zn) and even co-production of solar H2. Scale-up will be discussed showing how design correlations are developed with reactors of various sizes along with principles for synthesis of hard- or soft-agglomerates. Coating of nanoparticles with oxide or carbon films in flame and hot wall reactors will be discussed.

Technology Focus

nano particles A scalable, dry technology for synthesis of high purity nanoparticles with closely controlled characteristics is presented. This is advantageous over classic wet chemistry technologies (sol-gel or precipitation) as it does not use their multiple processing steps (e.g. washing, drying, calcinations etc.) and high volumes of liquid byproducts. Today industry uses dry technology for manufacture of carbon blacks and simple oxides after several years of evolutionary research. As a result, it is practically impossible to use these units for synthesis of functional inorganic (mixed ceramic or metal-ceramic) nanoparticles without going through the same costly and time-consuming cycle as shareholders have no patience or stomach for it. Major breakthroughs in academia, however, recently have placed dry synthesis of nanoparticles on a firm scientific basis allowing now synthesis of these materials in appreciable volumes and competitive prices creating renewed interest in dry processes and products. The focus now shifts to an integrated process development focusing on final product performance rather than particle characteristics through close interaction of particle specialists with end users. Special emphasis is placed on the degree of particle agglomeration and its control as well as on nanoparticles with designed morphology and even layered composition for materials that people never thought that could make them just a few years ago.

Objective

This course will introduce this technology and show its accessibility and potential for manufacture of functional nanoparticles. It will go through its history to show how it survived the “death valley” from the laboratory to manufacturing for selected products. The most important theories will be given accompanied with tangible examples so one can approach a specific problem with systematic reasoning and full utilization of the literature. Diverse examples will be given through analyzing and discussing a number of new products and processes using dry technologies in a relaxed atmosphere and through motivating lectures.

Course Contents

nano particle synthesis

1. Overview and History (1h)

Nanoparticles: Origins, Significance and Applications. Is it a Bubble? Health Issues. Cost. The evolution of today’s industry for manufacture of carbon blacks, fumed silica, pigmentary titania, ZnO, filamentary nickel, optical fibers and, most recently, for metallic and ceramic nanoparticles. Pros and Cons of Current Processes: Flame and Hot-Wall reactors.

2. Fundamentals (1h)

Definitions and Particle size Distribution. Brownian Motion and Particle Diffusion. Thermophoretic Sampling and Particle Characterization. Aerosol Coagulation in the Continuum and Free-Molecular Regimes, Self-Preserving Distributions, Agglomeration, Fractal-like Particles. Critical, Kelvin or minimum Particle Size, Condensation and Nucleation.

3. Principles for Process Design and Operation (1.5h)

Controlled flame synthesis of nanoparticles. Chemistry affects particle characteristics. Reactor design by computational fluid and particle dynamics. Process Scale-up and correlations. Hard- and Soft-Agglomerates.

4. Novel Products and Applications (2.5h)

4.1 Flame-made catalysts for DeNOx removal (V2O5/TiO2), polymer synthesis (TiO2/SiO2) and chiral pharmaceuticals (Pt/Al2O3) manufacture, Pt/Ba/Al2O3 for NOx storage, automotive CeO2/ZrO2 as well as photocatalysts (Pt/TiO2 or Ag/ZnO)
4.2 Mixed ceramics: Stable ZnO Quantum Dots for UV-filters by doping with silica, Dental nanocomposites (non-agglomerated SiO2) or Translucent Ta2O5/SiO2 in polymer matrices.
4.3 Hot-wall reactors for metal (Bi, Pd, Al, Zn) and non-oxide (AlN, B4C) nanoparticles and even for co-production of solar H2 with Zn/ZnO nanostructured particles.
4.4 Coatings: Carbon or ceramic oxide films on titania or silica nanoparticles.
4.5 Sensors: Flame synthesis of sensing particles for organics (TiO2) and their direct deposition (Pt/SnO2) on electrodes resulting in highly accessible porous films and sensors.
4.6 Solid or hollow ceramic particles and nanorods by emulsion/solution combustion.

Who Should Attend

The course is aimed for scientists (chemistry and physics) and engineers (chemical -mechanical) in research and development of processes involving fine particles for batteries, films, phosphors, catalysts, polishing, medical and dental nanocomposite materials (prosthetics), pigments, optical fibers, precious metals (Ag, Au, Pt, Pd), sunscreens, cosmetics, fuel cells, solar energy storage.

Instructor

Sotiris Pratsinis Dr. Sotiris E. Pratsinis (PhD UCLA 1985) is Professor of Process Engineering (www.ptl.ethz.ch) at the Swiss Federal Institute of Technology (ETH Zurich), Switzerland since 1998. His research centers on aerosol processing of nanoparticles with applications in catalysts, ceramics, sensors, batteries, dental and food materials. His program has been funded by the U.S. and Swiss National Science Foundations as well as by DuPont, Nestle, Toyota, Ivoclar-Vivadent etc. Prior to this he was Professor and Interim Head of Chemical Engineering at the University of Cincinnati, Ohio (1985-98). Prof. Pratsinis has graduated 16 and currently supervises nine PhD students with whom he has published over 200 refereed articles and book chapters on synthesis of nano-TiO2, SiO2, ZnO, CeO2 as well nanocomposites, lightguides and noble metal — ceramics. He has also six patents licensed to Dow Chemical, Degussa and Hosokawa-Micron. He has received the 1988 Kenneth T. Whitby Award of the American Association for Aerosol Research, the 1989 Presidential Young Investigator Award by the U.S. National Science Foundation and the 1995 Marian Smoluchowski Award by the European Aerosol Association and the 2003 Thomas Baron Award by the American Institute of Chemical Engineers (AIChE). He is European Editor of the Journal of Nanoparticle Research and on the Editorial Boards of the Powder Technology, Journal of Aerosol Science, Advanced Powder Technology, Particle and Particle Systems Characterization and KONA Powder and Particle as well as on the Advisory Board of the Australian Research Council Centre on Functional Nanomaterials and on the Science Advisory Board, Harvard School of Public Health - International Initiative for the Environment and Public Health.

 
 

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