Physical, Chemical and Electromagnetic Wave-induced Processes in Microdroplets

摘要/ ABSTRACT摘要：本研究的目的是研究均匀微液滴和层状微液滴的成核、光化学和化学反应。实验将对悬浮在电动天平中的单个液滴和由振动孔式气溶胶发生器产生的高度单分散的液滴进行实验。弹性和非弹性光散射技术，基于在散射光中观察到的共振（即强度峰），将用于确定均匀和分层液滴的大小和折射率。微液滴中的液固分离过程（即成核）将被研究，以了解控制固体颗粒结构的机制，微液滴层状液滴的形成表明，共振条件下微液滴中的光化学反应速率显着提高。理论分析的结果将用在波长与共振相对应的光照射下的微液滴中发生的光化学反应的实验数据进行检验。在含MnSO4的水溶液液滴中氧化SO2的实验表明，可以得到准确的反应动力学数据。在这个项目中，将研究用于生成固体颗粒的液滴-蒸汽反应，以确定是否可以通过液滴相反应改变平行串联反应中某一产物的选择性。最后，将从理论上和实验上考察包覆惰性不混相层的核心液滴与气相反应物之间的反应，以了解气层界面面积和层的扩散阻力对总反应速率的影响。

ABSTRACT CTS 96-18283 The objectives of the proposed research are to examine nucleation, photochemical and chemical reactions in homogeneous and layered microdroplets. Experiments will be conducted on single droplets suspended in an electrodynamic balance and on highly monodisperse droplets generated by a vibrating orifice aerosol generator. Elastic and inelastic light scattering techniques, based on resonances (i.e., intensity peaks) observes in scattered light, will be used to determine size and refractive indices of homogeneous and layered droplets. Liquid-solid phase separation processes (i.e., nucleation) in microdroplets will be examined to understand the mechanisms that control the structures of solid particles and the formation of layered droplets with microdroplets suggests that photochemical reaction rates in microdroplets under resonance conditions enhance significantly. The results of the theoretical analysis will be tested with experimental data on photochemical reactions occurring in microdroplets illuminated by light whose wavelength corresponds to a resonance. Prior experiments on oxidation of SO2 in aqueous solution droplets containing MnSO4 show that accurate data on reaction kinetics can be obtained. In this project droplet-vapor reactions used for generation of solid particles will be examined to determine whether the selectivity of one of the products in a parallel-series reaction can be altered by the droplet phase reaction. Finally, reactions between core droplets coated with inert immiscible layers and gas phase reactants will be examined theoretically and experimentally to understand the effects of the gas-layer interfacial area and diffusional resistance of the layer on the overall reaction rate.