SGER: Structure and Phase Behavior of Charged and Polymer-Containing Colloidal Dispersions

吴建中，加州滨江大学“SGER：带电聚合物胶体分散体的结构和相行为“胶体分散体广泛应用于光子晶体、催化剂、膜、多孔电极和先进陶瓷等现代材料的制造。这些应用需要理论指导来理解界面和热力学现象，如胶体稳定性，结构特性和相行为，这些现象取决于多个参数，包括粒度和浓度，电荷密度，离子强度，溶剂和溶解聚合物的性质，以及限制几何形状。为了满足这一要求，本研究结合统计力学的理论方法和小角中子散射（SANS）实验，建立一个统一的分子框架定量描述带电和含聚合物的胶体体系的结构和热力学性质。该探索性研究项目包括四个主要部分：1）胶体分散体微观结构的密度泛函理论; 2）计算对和多体胶体力和胶体结构，重点是含多价盐离子和聚合物的胶体; 3）计算胶体相行为，包括结构有序和亚稳流体-流体平衡; 4）聚-N-异丙基丙烯酰胺（PNIPAM）分散体的实验，用于校正计算结果。热响应性PNIPAM分散体被选择在这个探索性研究中，因为颗粒的物理化学性质和胶体力可以通过调节制备条件和水溶液的组成来容易地控制。胶体相图，结构因子，离子分布，渗透第二维里系数，将使用小角中子散射（SANS）和常规的静态和动态光散射研究带电以及含聚合物的PNIPAM分散体的粒径分布（SLS和DLS）这项探索性的研究具有显着的智力价值，其协同结合新的理论，用SANS表示复杂体系的界面结构和热力学性质。在这项工作中开发的分子模型将是有用的，软凝聚态物质的许多其他应用中，为开发理论指导方针，在选择的解决方案的条件下，在制造新一代的纳米结构材料使用亚微米building blocks.Broader ImpactsThis SGER研究项目可以导致一些广泛的影响。首先，这项工作的结果将提供胶体自组装的理论和实验，将是感兴趣的本科生和研究生在相关领域工作的新课程的基本基础。在该领域接受培训的学生将非常有市场，并将能够在纳米技术领域追求高效的职业生涯。其次，这项工作将为加州大学滨江分校的社会经济弱势学生提供支持，使他们能够参与研究，并获得理论建模和中子散射等尖端实验技术方面的跨学科技能。最后，这一探索性工作产生的出版物将对界面材料相关的基础研究和技术应用产生重大影响。

Wu, JianzhongU of Cal - Riverside "SGER: Structure and Phase Behavior of Charged Polymer-Containing Colloidal Dispersions"Colloidal dispersions are broadly applied in the fabrication of modern materials such as photonic crystals, catalysts, membranes, porous electrodes, and advanced ceramics. These applications require theoretical guidelines for understanding interfacial and thermodynamic phenomena such as colloidal stability, structural properties, and phase behavior that depend on multiple parameters, including particle size and concentration, charge density, ionic strength, properties of solvent and dissolved polymers, and confining geometry. To meet this requirement, the present research combines theoretical methods from statistical mechanics with small angle neutron scattering (SANS) experiments to establish a unified molecular framework for quantitative description of structural and thermodynamic properties of charged and polymer-containing colloidal systems. This exploratory research project consists of four major components: 1) a density functional theory for the microscopic structures of colloidal dispersions; 2) calculating pair and multibody colloidal forces and colloidal structure with an emphasis on those containing multivalent salt ions and polymers; 3) calculating colloidal phase behavior including structural ordering and metastable fluid-fluid equilibrium; 4) Experiments on poly-N-isopropylacrylamide (PNIPAM) dispersions for the calibration of calculated results. Thermally responsive PNIPAM dispersion is selected in this exploratory research because the physiochemical properties of the particles and the colloidal forces can be easily controlled by tuning the preparation conditions and the composition of the aqueous solution. The colloidal phase diagrams, structure factors, ionic distributions, osmotic second virial coefficients, and particle size distributions of charged as well as polymer-containing PNIPAM dispersions will be studied using small-angle neutron scattering (SANS) and conventional static and dynamic light scattering (SLS and DLS) measurements.Intellectual MeritsThis exploratory research holds significant intellectual merits for its synergetic combination of novel theoretical approaches with SANS to represent the interfacial structural and thermodynamic properties of complex systems. The molecular models developed in this work will be useful, among numerous other applications of soft condensed matter, for developing theoretical guidelines in the selection of solution conditions during the fabrication of a new generation of nanostructured materials using submicron building blocks.Broader ImpactsThis SGER research project can lead to a number of broad impacts. First, results from this work will provide the essential basis for new courses on theory and experiment of colloidal self-assembly that will be of interest to both undergraduate and graduate students working in related fields. Students trained in this area will be highly marketable and will be able to pursue highly productive careers in nanotechnology. Second, this work will provide support for socioeconomically disadvantaged students from the University of California at Riverside to participate in research and gain interdisciplinary skills in theoretical modeling and cutting edge experimental techniques such as neutron scattering. Finally, the publications resulting from this exploratory work will have significant impacts on both fundamental research and technological applications related to materials at the interface.