The role of the medium in the effective-sphere interpretation of holographic particle characterization data
The role of the medium in the effective-sphere interpretation of holographic particle characterization data
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DOI：
10.1039/c9sm01916b
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发表时间：
2020-01-28
期刊：
影响因子：
3.4
通讯作者：
Grier, David G.
中科院分区：
文献类型：
--
作者：
Odete, Mary Ann;Cheong, Fook Chiong;Grier, David G.
用Lorenz-Mie光散射理论分析微米级胶体球体的同轴全息图，可以得到球体直径和折射率的精确测量。同样的技术也可以用来表征多孔性和不规则形状的胶体颗粒，只要用有效介质理论解释提取的参数来表示等效有效球的性质。在这里，我们证明了有效球模型一致地解释了当介质填充多孔颗粒的孔隙时介质的折射率的变化，从而得到关于这种颗粒的结构和组成的定量信息。除了样本平均孔隙度外，全息灌注法还可以测量孔隙度的多分散性。我们通过对介孔球体、分形蛋白质聚集体和不规则纳米粒子聚集体的测量，展示了这些能力，所有这些都值得注意，因为它们具有工业意义。
The in-line hologram of a micrometer-scale colloidal sphere can be analyzed with the Lorenz-Mie theory of light scattering to obtain precise measurements of the sphere's diameter and refractive index. The same technique also can be used to characterize porous and irregularly shaped colloidal particles provided that the extracted parameters are interpreted with effective-medium theory to represent the properties of an equivalent effective sphere. Here, we demonstrate that the effective-sphere model consistently accounts for changes in the refractive index of the medium as it fills the pores of porous particles and therefore yields quantitative information about such particles' structure and composition. In addition to the sample-averaged porosity, holographic perfusion porosimetry gauges the polydispersity of the porosity. We demonstrate these capabilities through measurements on mesoporous spheres, fractal protein aggregates and irregular nanoparticle agglomerates, all of which are noteworthy for their industrial significance.