This work aims at expanding the applicability of photon density wave spectroscopy (PDWS) to in-situ characterization of dispersed aggregates of spherical primary particles. For this purpose, an approximate optical model within the Rayleigh-Debye-Gans-theory was developed that links the experimentally determined reduced scattering coefficients with the fractal dimension and the radius of gyration of the dispersed aggregates. The model includes an analytical expression for the anisotropy factor of fractal aggregates that has not been suggested before to our best knowledge. PDWS measurements of suspensions of aggregated amorphous silica and titania nanoparticles were performed and the obtained and were used to calculate the hydrodynamic radii of the investigated aggregates. The latter were referenced by dynamic light scattering experiments. In contrast to the other reference techniques, PDWS and gravimetric analyses were performed without dilution of the investigated samples. The samples differed in solvent, primary particle size, aggregate size, and aggregate density.

中文翻译：

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表达分形聚集体的各向异性因子，以便使用光子密度波谱对其进行表征


这项工作旨在扩大光子密度波谱（PDWS）在球形初级粒子分散聚集体的原位表征中的适用性。为此，开发了瑞利-德拜-甘斯理论中的近似光学模型，该模型将实验确定的降低散射系数与分散聚集体的分形维数和回转半径联系起来。该模型包括分形聚合各向异性因子的分析表达式，据我们所知，此前尚未提出过该表达式。对聚集的无定形二氧化硅和二氧化钛纳米颗粒的悬浮液进行 PDWS 测量，并将所得结果用于计算所研究聚集体的流体动力学半径。后者被动态光散射实验引用。与其他参考技术相比，PDWS 和重量分析是在不稀释所研究样品的情况下进行的。样品的溶剂、初级粒径、聚集体尺寸和聚集体密度不同。