Dielectric spectroscopy and SAXS investigations on self-organization mechanism of biologically-originated systems

本研究的主要目的是阐明生物起源的两亲性聚合物在水中的自组织机制，其中静态结构（如颗粒结构和颗粒间相互作用势）与动力学方面（如溶剂的高频动力学和水化行为）之间的相互作用通过精心结合的光谱和散射技术（如介电光谱和小角x射线散射（SAXS））进行了仔细研究。首次阐明了氢键液体介电光谱与拉曼光谱关系的一般规律；集体弛豫过程，即对涉及远距离偶极-偶极相互作用的氢键液体特有的介电谱的主要贡献，实际上不是拉曼活性的。研究结果将为全面理解氢键流体动力学的微观-宏观关系奠定基础。我们研究了更多的纳米组装（特别是胶束）的结构和分子动力学，这些纳米组装是由生物起源的和合成的两亲体在水中形成的。我们发现，利用GIFT（广义间接傅立叶变换）技术进行精确的静态结构因子分析，结合电介质光谱的动态水化数分析，可以定量地解释水化水对胶束排除体积的影响及其对体系等温压缩率的贡献。我们的SAXS和流变学数据清楚地表明，由于自由能优化，糖基表面活性剂微乳的相行为与胶束延伸成棒状或虫状密切相关。此外，我们试图构建一种新的方法来计算径向分布函数（rdf）和/或从实验静态结构因子对相关函数，引入了所谓的SQ-IFT（结构因子间接傅立叶变换）方法，并证实了它的通用适用性。为了从液体衍射数据计算分子液体的rdf，不再需要传统使用的散射矢量加权结构函数。同时，SQ-IFT可以提供溶液中蛋白质-蛋白质空间相关性的潜在无模型真实空间信息。少

The main goal of this study is to clarify self-organization mechanisms of biologically-originated amphiphilic polymers in water, where an interplay between static structures, such as particle structure and interparticle interaction potential, and dynamical aspects like high-frequency dynamics of solvents and hydration behavior has been scrutinized by elaborately combined spectroscopic and scattering techniques, e.g., dielectric spectroscopy and small-angle X-ray scattering (SAXS).A general rule that can consistently explain relation between dielectric and Raman spectra of hydrogen-bond liquids has been for the first time elucidated ; the collective relaxation process, i.e., the main contribution to the dielectric spectrum specific to hydrogen-bond liquids involving a long range dipole-dipole interaction, is virtually not Raman active. The results will lay the foundation for complete understanding microscopic-macroscopic correlation in hydrogen-bond liquid dynamics.We have examined stat … More ic structures and molecular dynamics of a nano-assembly (in particular, a micelle) that is formed by biologically-originated as well as synthetic amphihilie in water. We have found that an accurate static structure factor analysis by GIFT (generalized indirect Fourier transformation) technique combined with dynamic hydration number analysis by dielectric spectroscopy can quantitatively explain the effects of hydrated water on excluded volume of micelles and its contribution to isothermal compressibility of the system. Our SAXS and rheology data clearly demonstrate that phase behavior of sugar-based surfactant microemulsions are closely linked with elongation of a micelle into rodlike or wormlike ones due to free-energy optimization.Furthermore, we have attempted to construct a new approach to the calculation of the radial distribution functions (RDFs) and/or pair correlation functions from experimental static structure factor, introducing the so-called SQ-IFT (structure factor indirect Fourier transformation) method, and confirmed its versatile applicability. To calculate the RDFs of molecular liquids from liquid diffraction data, a conventionally utilized scattering vector-weighted structure function is no longer required. Simultaneously, SQ-IFT can provide potential model-free real space information on protein-protein spatial correlations in solution. Less