Multidimensional analysis of nanoparticulate structures using analytical ultracentrifugation with integrated multiwavelength detection

本项目的目的是研制分析超速离心机(AUC)中的多波长检测器(MWL检测器)，并将其作为多维粒子分析方法在粒子技术中的应用。利用MWL-AUC同时获得了沉积和消光数据。这些数据可用于确定广泛的多峰颗粒尺寸分布(PSD)以及纳米颗粒(NPs)的形状和光学性质。第一个资助期产生的关键问题将在第二个资助期通过制定新的方法加以补充和完善。借助于动态转子速度斜坡，甚至可以高分辨率地分析从几纳米到几微米的非常宽的多模式PSD。在第一个资助期开发的一个软件包(HDR-MULTIFIT)将得到扩展，以便能够描述复杂的沉积和漂浮系统。由于基于直接边界建模的新分析例程，实现了更大的动态范围。进一步的重点将放在直径小于10 nm的半导体纳米粒子的表征上。新的算法将允许以高分辨率同时确定ZnO、CuInS2、CdSe和CDS纳米粒子的大小和密度。此外，还将研究氧化锌和银纳米管的形状。为此，将调整和推广在第一个供资时期为氧化石墨烯制定的方法。纳米管的厚度和长度分布可以在不需要成像技术的情况下通过使用扫描迁移率颗粒测量仪进行补充实验来确定。首先将通过使用球形NPs的比较研究来验证这两种技术所需的相关性。除了纳米粒子的大小和形状外，还可以使用强大的数据评估技术来获得光学性质。在自由软件包中的实施将与B.Demeler教授(德克萨斯大学)和W.F.Stafford博士(哈佛医学院)密切合作。通过这种方法，半导体NPs的尺寸-带隙关联将可以使用AUC来实现。对于片状颗粒，可以确定银或金在二氧化硅或聚苯乙烯纳米颗粒上的表面覆盖率。此外，颗粒的形态可以与光学性质相关联。此外，还将开发算法，通过MWL-AUC确定颜料等材料的折射率。

Objective of this project is the development of the multiwavelength-detector (MWL-detector) in the analytical ultracentrifuge (AUC) and its application in particle technology as a method for multidimensional particle analysis. Sedimentation and extinction data are obtained simultaneously by means of MWL-AUC. Such data can be used to determine broad multimodal particle size distributions (PSDs) as well as the shape and optical properties of nanoparticles (NPs). The key questions arising from the first funding period will be complemented and completed in the second funding period by the development of new methods. By means of a dynamic rotor speed ramp even very broad multimodal PSDs reaching from a few nanometers to several microns can be analyzed with high resolution. A software package developed in the first funding period (HDR-MULTIFIT) will be extended in such way that complex sedimenting and floating systems can be characterized. An increased dynamic range is accomplished due to a new analysis routine based on direct boundary modelling. Further emphasis will be put on the characterization of semiconductor NPs less than 10 nm in diameter. New algorithms will allow to determine the size and density of ZnO, CuInS2, CdSe and CdS NPs simultaneously and with high resolution. Furthermore, the shape of ZnO- and silver-nanotubes will be investigated. For this purpose, methods developed in the first funding period for graphene oxide will be adapted and extended. The thicknesses and length distributions of the nanotubes can be determined without the necessity of imaging techniques by conducting complementary experiments using a scanning mobility particles sizer. The required correlation of both techniques will first be validated by means of comparative studies using spherical NPs. Besides size and shape of NPs also optical properties become available using strong data evaluation techniques. Implementations in free software packages will be realized in close collaboration with Prof. B. Demeler (U Texas) and Dr. W. F. Stafford (Harvard Medical School). By means of this the size - band gap correlation of semiconductor NPs will become accessible using AUC. For patchy particles the surface coverage of silver or gold on SiO2 or polystyrene NPs can be determined. Moreover, the particle morphology can be correlated with the optical properties. In addition, algorithms will be developed to determine the refractive indices of materials such as pigments by means of MWL-AUC.