Analytical Ultracentrifuge

分析超离心法（AUC）是一种胶体分析方法，可对分散体系进行全面表征。分散在溶剂中的纳米颗粒或大分子在离心场中分离，而吸收或干涉光学器件允许在样品池中观察该过程。 数据评估分别从沉积边界速度和加宽产生沉积和扩散系数及其分布。通过这些参数和测量，可以获得颗粒尺寸、形状以及分子量和样品密度。相互作用系统也可以通过AUC进行分析;沉降-扩散-平衡实验产生化学平衡的化学计量和平衡常数。AUC是一种绝对方法。 由于整个系统的分离和光学检测，获得了具有高统计意义的数据。实际上，AUC是一种高分辨率技术，可以分辨出粒径范围内的差异。使用现代瑞利干涉光学，非常稀和集中的色散都可以分析。光吸收样品可以使用多波长吸光度（MWA）检测器进行表征，这允许识别复杂混合物中的不同组分。对于金属和半导体纳米颗粒，MWA探测器可以详细表征尺寸相关的光学特性（分别归因于等离子体共振和量子尺寸效应）。在本项目中，分析型超吸收光谱仪将用于解决各种问题。一方面，它将用于研究从溶液形成固体的早期阶段，即，表征最小的簇、核和中间体，以及它们与添加剂的相互作用，从简单分子到蛋白质。另一方面，该设备将用于回答半导体纳米结构，多功能两亲物，多孔有机-无机固体，复杂的纳米颗粒和纳米颗粒超结构，以及合成聚合物等领域的各种问题，为生物材料的使用量身定制。所要求的设备对于分析固体形成的早期阶段是不可或缺的，并且将对回答上述化学材料科学领域中的各种问题做出至关重要的贡献。

Analytical Ultracentrifugation (AUC) is a method of colloid analytics, which enables a complete characterization of dispersed systems. Nanoparticles or macromolecules, dispersed in a solvent, are separated in a centrifugal field, while absorption or interference optics allow observing this process in the sample cell. The data evaluation yields the sedimentation and diffusion coefficients, and their distributions, from the sedimenting boundary velocity and broadening, respectively. From these parameters and measurements, particle size, shape as well as molecular weight and sample density are accessible. Interacting systems can also be analyzed by means of AUC; sedimentation-diffusion-equilibrium experiments yield the stoichiometry and equilibrium constant of chemical equilibria.AUC is an absolute method. Due to the fractionation and optical detection of the entire system, data with high statistical significance are obtained. Indeed, AUC is a high-resolution technique, which can resolve differences between particle sizes in the Ångström range. Using modern Rayleigh interference optics, both very dilute and concentrated dispersions can be analyzed. Light absorbing samples can be characterized using multiwavelength absorbance (MWA) detectors, which allows identifying distinct components in complex mixtures. In case of metal and semiconductor nanoparticles, the MWA detector allows characterizing size dependent optical properties (due to plasmon resonance and quantum size effects, respectively) in detail.In this project, the Analytical Ultracentrifuge will be used to address various questions. On one hand, it will serve to study the early stages of the formation of solids from solution, i.e., to characterize smallest clusters, nuclei and intermediates, as well as their interactions with additives, ranging from simple molecules to proteins. On the other hand, the device will be used to answer various questions in the areas of semiconductor nanostructures, multifunctional amphiphiles, porous organic-inorganic solids, complex nanoparticles and nanoparticle superstructures, as well as synthetic polymers, tailor-made for the use in biomaterials. The requested device is literally indispensable for the analyses of the early stages of the formation of solids, and will crucially contribute to answering various questions in the above mentioned fields of chemical materials science.