Identifying time-dependent changes in the morphology of an individual aerosol particle from its light scattering pattern
Identifying time-dependent changes in the morphology of an individual aerosol particle from its light scattering pattern
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DOI：
10.1080/02786826.2019.1661351
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发表时间：
2019-09-14
影响因子：
5.2
通讯作者：
Reid, Jonathan
中科院分区：
文献类型：
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作者：
Haddrell, Allen;Rovelli, Grazia;Reid, Jonathan
气溶胶液滴/颗粒的物理、化学和生物学性质取决于液滴/颗粒本身的形态;例如，液滴将以与固体颗粒根本不同的方式被气相中的氧化剂处理。另外，考虑到它们的小尺寸，气溶胶液滴可以在毫秒量级的时间尺度上改变相位（例如，潮解或结晶）。因此，能够快速和容易地估计液滴/颗粒的形态是至关重要的，特别是在复杂的气溶胶过程，如喷雾干燥和溶解的解释。这里要报道的是一种新的方法，其使用穿过液滴的前向散射光（类似于32度<θ <类似于58度）来确定液滴/颗粒形态。该算法是通过对各种颗粒形态的一百多万个单独的相函数进行定性分析而开发的。该算法可以区分四种不同的形态：均匀，核/壳，夹杂物，和非球形/不均匀。该算法适用于半径在近似5微米到近似30微米之间的液滴。相分析的速率取决于收集光散射的速率，在这里提供的数据中，每10毫秒报告一次颗粒的形态。在这项工作中提出的算法的相位识别的准确性是非常高的（>90%），其效用是加强了散射光的收集，这使得一个单独的液滴被探测超过每秒100次的高频率。虽然不是绝对的每一个相函数分析时，再加上重复和高通量，这里提出的算法可以是一个有价值的工具，轻松，容易地确定动态气溶胶系统中的颗粒形态。版权所有（c）2019美国气溶胶研究协会
The physical, chemical, and biological properties of an aerosol droplet/particle are dependent on the morphology of the droplet/particle itself; for example, a liquid droplet will be processed by oxidants in the gas phase in a fundamentally different way than a solid particle. Additionally, given their small size, aerosol droplets may change phase over timescales in the order of milliseconds (e.g., deliquescence or crystallisation). Thus, ability to rapidly and easily estimate the morphology of a droplet/particle is critical, especially in the interpretation of complex aerosol processes such as spray drying and dissolution. To be reported here is a novel method that uses the forward scattered light (similar to 32 degrees < theta < similar to 58 degrees) passed through a droplet to determine the droplet/particles morphology. The algorithm was developed through the qualitative analysis of over one million individual phase functions of various particle morphologies. The algorithm can differentiate between four different morphologies: homogeneous, core/shell, with inclusions, and non-spherical/inhomogeneous. The algorithm is applicable to droplets between similar to 5 to similar to 30 microns in radius. The rate of phase analysis is dependent on the rate in which the light scatter can be collected, in the data presented here a particle's morphology is reported every 10 milliseconds. The accuracy of the phase identification with the algorithm proposed in this work is very high (>90%); its utility is strengthened by the high frequency of the collection of scattered light, which allows an individual droplet to be probed upwards of over 100 times per second. Although not absolute on every phase function analysis, when coupled with repetition and high throughput, the algorithm presented here can be a valuable tool to easily and readily determine particle morphology in dynamic aerosol systems. Copyright (c) 2019 American Association for Aerosol Research