Experimental Tools For Investigating Nanoparticles

1. MECHANICAL & AEROSPACE SEMINAR November 30, 2004 - 3:30 p.m. – 4:30 p.m. Room 214 Mechanical Engineering Annex CO-SPONSORED BY ISC Experimental Tools For Investigating Nanoparticles Dr. Da-Ren Chen Washington University – St. Louis, MO Abstract Nanotechnology, one of ongoing international initiatives, will be a strategic branch of science and engineering for the 21st century. Nanoparticles are considered as the building blocks in nanotechnology. Experimental tools play an important role in developing the nanoscale science and engineering. These tools bring together researchers from multiple disciplines, e.g., material scientists, engineers, biologists and chemists, to pursue the common goal of investigating nanoscale phenomena. In the aerosol field, several tools have been developed to generate, measure, classify and manipulate nanoparticles in the diameters ranging from 3 to 100 nm. Several recently developed experimental and numerical tools will be discussed in this presentation. We have developed a nanometer differential mobility analyzer (Nano-DMA) to measure and classify 3 to 100 nm nanoparticles. Based on the DMA technique a fast-scan electrical nanoparticle sizer has demonstrated the high resolution and fast response capability to measure bimodal nanoparticle distributions in jet and diesel engine emissions as well as the particle formation in the laser ablation process. To further enhance the sensitivity of detecting nanoparticles we have successfully developed a high efficiency nanoparticle charger. We have further developed a stackable DMA, which is capable of classifying monodisperse particles of different sizes simultaneously and having a particle size scan rate at the fraction of a second. Using the particle inertia effect we have demonstrated the virtual impactor and coaxial cyclone able to separate particles in nanometer diameter range. An electrospray system has also been developed to produce monodisperse nanoparticles in the 2 nm to 2 µm size range. Finally, the development of a continuous gene-gun based on the electrospray principle, illustrates the importance of multidisciplinary approach in nanotechnology ________________________________________________________________________ Da-Ren Chen, Ph.D., is now an assistant professor at Department of Mechanical and Aerospace Engineering, joint program in Environmental Engineering, Washington University in St. Louis. He received his MS (1993) and Ph. D. (1997) degrees from the Particle Technology Laboratory, University of Minnesota. He is the principal inventor of electrospray monodisperse nanoparticle generator, Nano-DMA (for nanoparticle sizing), high-through nanoparticle charger, fast scan aerosol size analyzer, continuous gene transfector and other aerosol tools. He holds ten US and two international patents in the aerosol technology. He receives Sheldon K. Friedlander Award (1997) and Smoluchowski Award (2002) for his significant contribution on nanoparticle Instrumentation. He has also intensive experience on atmospheric aerosol, computational fluid and aerosol dynamics, aerosol sampling and measurements, aerosol filtration, micro-contamination control in semiconductor processing equipments, and nanoparticle synthesis for bio- and medical applications. Department of Mechanical & Aerospace Engineering (Refreshments Served at 3:15 p.m.)