Relating the aerosol particle structure to the particle transport properties using ultra small angle X-ray scattering*

The structure and morphology of airborne particles has a significant effect on its transport properties and deposition characteristics in human respiratory systems. A number of studies have investigated fractal characteristics of aerosol particles and their mobility equivalent diameters, particularly the proportionality between the mobility size and fractal dimension,^1-6 however, the impact of the fractal topology^7,8 that includes the branch content, branch length, aggregate mass, and size have not yet been explored. The objective of this study was to probe the fractal structure of aerosol agglomerates using USAXS and application of the Kirkwood-Riseman theory⁹ using a recently developed monomer-cluster growth simulation¹⁰. For this purpose, size classified nanoaggregates of silver generated in a laboratory and commercial fumed silica with mobility sizes smaller than 200 nm were examined using X-ray scattering. Correlations between the fractal structure from USAXS, the theoretically estimated mobility  size and experimentally measured mobility size will be reported.

1 Wang and Sorensen. Physical Review E 1999, 60, 3036

2 Rogak et al. Aerosol Sci. Technol. 1993, 18, 25–47

3 Tandon and Rosner. Ind. Eng. Chem. Res. 1995, 34, 3265–3277

4 Wiltzius. Phys. Rev. Lett. 1987, 58, 710–713

5 Ku and Kulkarni. Aerosol Sci. Technol. 2018, 52, 597-608

6 Ku et al. Nanotechnology 2006, 17, 3613-3621

7 Beaucage. Phys. Rev. E 2004, 70, 031401

8 Beaucage et al. J. Appl. Crystallogr. 2004, 37, 523−535

9 Kirkwood and Riseman. J. Chem. Phys. 1948, 16, 565–573

10 Mulderig et al. J. Aerosol Sci. 2017, 109, 28−37