Hygroscopic Properties of Microstructured Aerosols

University Of Kentucky Research Foundation, Lexington KY

Investigators

Abstract

During their lifetime, ambient aerosols from various sources coagulate with other aerosols or cloud droplets, in addition to undergoing alteration through heterogeneous processes, such as condensation and chemical reactions. These processes lead to the formation of aerosols with complex microstructures that include solid particles dispersed in liquid droplets, or layered particles. Aerosol microstructures play a significant role in determining their climatic impact by altering their role in atmospheric physical, chemical and radiative processes. Currently, no technique is available for volumetric time and space-resolved physical and chemical characterization of microstructured aerosols. Experiments will be conducted on single nanoparticles manufactured to have various types of microstructures. Different methods will be tested for generating nanoparticles with various chosen properties. One class of these particles, soot particles with surface coatings of various compounds, will be suspended in electrodynamic balances under controlled environments. The particles will be observed as environmental humidity and temperature are varied to evaluate hygroscopic properties of these soot nanoparticles coated with hydrophilic and hydrophobic compounds, and how these properties vary with variation in chemical components and physical arrangements of the various coatings. This project will be conducted in collaboration with Prof. Reinhard Niessner of Technische Universitaet Muenchen. Successful completion of this work will lay the foundation for future exploration of variation of optical properties of these aerosols as environmental conditions vary. The intellectual merits of the project lie in the development of new tools for studying microstructured aerosols that play significant roles in atmospheric processes and climate. A successful outcome of the proposed research will be critically needed understanding of physical and chemical processes associated with microstructured soot aerosols. The research will provide laboratory training for a graduate student in non-traditional chemical engineering aspects, as well as provide him/her with an international research experience. The research knowledge from the project will impact both undergraduate and graduate education. In addition, high school students will be exposed to some aspects of the research.