New Measuring Technique for Multi-Dimensional Characterization of Nanoparticles

现有的颗粒表征方法通常测量颗粒的一种特定物理属性的分布。然而，对于非球形粒子，这通常不足以描述其所需的复杂性质。SPP 2045旨在根据不同的颗粒特性进行多维分级。因此，为了对分馏结果进行量化，必须能够全面地表征所涉及的颗粒体系的分散性质，并考虑到多种性质。这项研究计划的目的是发展一种新的测量原理，用于直接对亚微米粒子系统进行二维表征，它允许利用一个紧凑的设备来确定质量的完整的二维频率分布以及迁移率当量直径。从该多维分布可以得到进一步的信息，例如关于颗粒的形状和结构属性的分布。这种测量方法是基于现有的分析分离旋转圆柱形间隙中颗粒的方法，该方法现在扩展为叠加电场。为了对其传递函数进行全面的表征，建立了一个实验室装置。对分类过程中所有相关影响的详细模拟应允许对转移行为进行准确预测。为了从直接确定的关于速度和电压的2D分布中获得关于质量和迁移率直径的期望分布，该模型又是必需的。然而，由于这是一个数学上不适定的问题，因此需要一个合适的求逆算法。因此，这项研究项目还研究了应用新的数据反演策略来重建所需的二维分布。该方法将使用模型粒子和具有特定性质的复杂粒子系统进行连续测试。然后，该方法将用于SPP 2045的各种项目，以证明其评估各自分馏的能力，从而为这些项目做出重要贡献。预计这一研究项目还将在SPP之外，显著改善复杂粒子系统的表征，并将为更好地从根本上了解复杂粒子系统的分散性质做出重要贡献。

Existing particle characterization methods typically measure the distribution of one specific physical property of the particles. However, for non-spherical particles this is often not sufficient to describe their complex properties to the required extent. The SPP 2045 aims for a multi-dimensional fractionation according to different particle characteristics. Therefore, it is essential to be able to characterize the disperse properties of the involved particle systems comprehensively and regarding multiple properties in order to quantify the fractionation results. The aim of this research proposal is the development of a novel measuring principle for the direct 2D characterization of submicron particle systems, which allows to determine the complete, two-dimensional frequency distribution of the mass as well as the mobility equivalent diameter with the help of one compact device. From this multidimensional distribution, further information can be derived, e.g. on the distribution of shape and structural properties of the particles. The measurement method is based on an already existing method for the analytical separation of particles in a rotating cylindrical gap, which is now extended by a superimposed electric field. A laboratory set-up is built in order to characterize its transfer function thoroughly. A detailed simulation of all relevant effects during the classification shall allow a precise prediction of the transfer behaviour. This model is in turn necessary in order to obtain the desired distribution with regard to mass and mobility diameter from the directly determined 2D distribution with regard to speed and voltage. However, since this is a mathematically ill-posed problem, a suitable inversion algorithm is required. Therefore, this research project also addresses the application of novel data inversion strategies to reconstruct the desired two-dimensional distributions. The method is to be successively tested using model particles and complex particle systems with defined properties. The method will then be used in various projects of the SPP 2045 to demonstrate its ability to evaluate the respective fractionation and thus make an important contribution to these projects. It is expected that this research project will also contribute beyond the SPP to significantly improve the characterization of complex particle systems and will make an important contribution to a better fundamental understanding of the disperse properties of complex particle systems.