Hygroscopic Properties of Microstructured Aerosols

在其寿命期间，来自各种来源的环境气溶胶与其他气溶胶或云滴凝结，此外还通过非均相过程（如凝结和化学反应）进行改变。 这些过程导致形成具有复杂微观结构的气溶胶，包括分散在液滴中的固体颗粒或分层颗粒。 气溶胶微结构通过改变其在大气物理、化学和辐射过程中的作用，在确定其气候影响方面发挥着重要作用。 目前，还没有技术可以用于微结构气溶胶的体积时间和空间分辨的物理和化学表征，实验将在具有各种类型微结构的单个纳米颗粒上进行。 将测试不同的方法来生成具有各种选定特性的纳米颗粒。 这些颗粒中的一类，具有各种化合物的表面涂层的烟灰颗粒，将在受控环境下悬浮在电动天平中。 随着环境湿度和温度的变化，将观察颗粒，以评估涂覆有亲水性和疏水性化合物的这些烟灰纳米颗粒的吸湿性能，以及这些性能如何随着各种涂层的化学组分和物理布置的变化而变化。 该项目将与慕尼黑工业大学的Reinhard Niessner教授合作进行。 该项目的成功完成将为今后探索这些气溶胶光学特性随环境条件变化的规律奠定基础，其智力价值在于为研究在大气过程和气候中起重要作用的微结构气溶胶开发新的工具。 一个成功的结果，拟议的研究将迫切需要了解的物理和化学过程与微结构烟尘气溶胶。 该研究将为非传统化学工程方面的研究生提供实验室培训，并为他/她提供国际研究经验。 该项目的研究知识将影响本科和研究生教育。此外，高中生将接触到研究的某些方面。

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.