Max Eggersdorfer
Institute of Process of Engineering, Swiss Federal Institute of Technology, ETH Zurich
June 22, 2012 | 11:00 to 12:00 | 540 Cory Hall, DOP Center Conference Room
Host: Niels Quack
My research focuses on the simulation of nanoparticle growth by coagulation and sintering and real-time characterization methods of the former in the gas-phase. Although models exist to characterize agglomerates of spherical particles, up to now the primary particle size was obtained ex-situ from electron microscopy, nitrogen adsorption or extracted by small-angle X-ray scattering. This diameter is one of the key characteristics of nanomaterials as it frequently determines their catalytic, sensing, superparamagnetic, plasmonic, thermal and other properties. A new method is presented for extraction of the average primary particle diameter of fractal-like particles from nearly in-situ mass-mobility measurements. So, zirconia (ZrO₂) nanoparticles are generated by scalable spray combustion and their mobility diameter and mass are obtained by differential mobility analyzer (DMA) and aerosol particle mass (APM) analyzer measurements. Using this data, the density of zirconia and a power law extracted from our simulations, the structure and diameter of fractal-like particles is determined. This primary particle diameter is in good agreement with those obtained by ex-situ nitrogen adsorption and microscopic analysis. That way the effect of flame spray process parameters (e.g., precursor solution and oxygen flow rate as well as zirconium concentration) on fractal-like particle structure characteristics is investigated in detail during particle synthesis.
www.ptl.ethz.ch/people/phd_students/eggersdm
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