Acquisition of Analytical Ultracentrifuge for the Study of Interaction of Surfactants and Polymers

自然界和商业上的大量水基和非水基体系在同一溶液或悬浮液中含有一种或多种聚合物和表面活性剂。 在这样的系统中，聚合物和表面活性剂之间的相互作用，以及由这种相互作用形成的任何“复合物”赋予的性质的变化，在生物系统如膜和载体（脂质转运），以及食品、药物、化妆品、洗涤剂和各种其他化学系统的商业系统中可能是相当重要的。 含有这种混合物的许多商业产品已广泛用于不同领域，但这些产品的配制主要依赖于试验和误差测试。 显然，充分了解相关聚合物和表面活性剂的相互作用特性将大大有助于开发高效产品。 为此目的，我们建议获得一个分析超浓度计，包括两个光学系统，用于确定浓度分布。 两种重要类型的实验可以用分析超离心进行：在沉降平衡实验中，允许发展一种稳态条件，其中样品在离心场中沉降的趋势被其逆着如此建立的浓度梯度扩散的趋势所抵消。 在沉降速度实验中，测定分子向细胞底部移动的速度。 这产生沉降系数和扩散系数D，其可以与分子量和摩擦系数相关的形状的大分子的大小范围从几千到数千万道尔顿。 使用这种技术可以对溶液中聚合物和表面活性剂相互作用的动力学进行研究，这将为我们对表面活性剂，聚合物及其混合物的行为的认识提供一个飞跃。 我们将能够在表面活性剂混合物的研究中使用分析超滤，以了解表面活性剂类型，混合比和混合胶束的形状，组成和结构之间的关系。 另一个应用将是在我们的工作上的涂层和凝聚的纳米颗粒制备纳米复合材料，可能会导致显着的进步，在复合材料制造。 最近，我们已经扩大了我们的表面吸附现象的研究领域的聚合物（蛋白质）-表面活性剂的混合物系统。 分析型超滤仪提供聚合物（蛋白质）-表面活性剂复合物分子量分布的直接信息的独特能力在纳米级聚合物-表面活性剂域和这些域的溶解度的研究中是非常宝贵的。 因此，收购分析超浓缩系统将大大增强哥伦比亚大学NSF IUCR新型表面活性剂高级研究中心的能力，并使我们能够探索表面活性剂和聚合物应用的快速扩展前沿。

ABSTRACTCTS-9905217Somasundaran, P.Columbia UniversityA large number of aqueous and non-aqueous based systems in the nature and commerce contains one or more polymer and surfactants in the same solution or suspension. In such systems, interactions between polymers and surfactants, as well as changes resultant in properties conferred by any "complex" formed by such interactions, can be of considerable importance in biological systems such as membranes and carriers (lipid transport), and commercial systems of foods, pharmaceutics, cosmetics, detergents and various other chemical systems. Many commercial products containing such mixtures has been widely used in different areas, but formulation of these products has mainly depended on trial and error tests. Clearly a full knowledge of the interaction characteristics of relevant polymers and surfactants will greatly aid the development of efficient products. Toward this purpose we propose to acquire an analytical ultracentrifuge comprising two optical systems for determining concentration distribution. Two important types of experiments can be performed with the analytical ultracentrifuge: in the sedimentation equilibrium experiments, a steady state condition is allowed to develop in which the tendency of a sample to sediment in the centrifugal field is counterbalanced by its tendency to diffuse against the concentration gradient so established. In the sedimentation velocity experiment, the speed with which a molecule moves toward the bottom of the cell is determined. This yields the sedimentation coefficients, and the diffusion coefficient D, which can be related to the molecular weight and the frictional coefficient related to the shape of macromolecules ranging in size from several thousand to tens of millions of dolton. Studies that can be conducted on the dynamics of interactions of polymers and surfactants in solutions using this technique would provide a quantum leap in our knowledge of the behavior of surfactants, polymers and their mixtures. We will be able to use analytical ultracentrifuge also in our study of surfactant, mixtures to understand the relationship between surfactant type, mixing ration and the shape, composition and structure of mixed micelles. Another application will be in our work on coating and coagulation of nanosized particles for preparation of nanocomposites that could lead to significant advance in composite fabrication. Recently, we have expanded our studies of surface adsorption phenomena into the area of polymer (protein)-surfactant mixture systems. The unique capability of the Analytical Ultracentrifuge to provide direst information on the molecular weight distribution of polymer (protein)-surfactant complexes is invaluable in the study of Nan-size polymer-surfactant domains and the solubility of these domains. The acquisition of an Analytical Ultracentrifuge System will thus great enhance the capabilities of Columbia University NSF IUCR Center for Advanced Studies in Novel Surfactants, and will enable us to explore the rapidly expanding frontiers of surfactant and polymer applications.