GOALI: Colliods, Surfactants, and Polyelectrolytes

目标：胶体、表面活性剂和聚电解质

• 批准号: 0625047
• 负责人: Norman Wagner
• 金额: --
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0625047&HistoricalAwards=false
• 关键词: GOALI; Colliods; Surfactants; Polyelectrolytes

ABSTRACTNano-scale self-assembly of polyelectrolyte with surfactant into structured 'complex' fluids is at the heart of many contemporary scientific and commercial endeavors. It is a major emphasis of the specialty chemical industry, and enables advances in personal care products. The same chemistry and physics also dominates the non-specific interactions in biological systems and plays an important role in downstream purification and formulation of proteins and other pharmaceuticals. Despite the obvious importance these mixtures, there are significant gaps in the understanding of how polyelectrolytes and surfactants interact to form specific microstructures and to dictate colloidal-scale properties. The structures are typically on the nanometer-scale and are used to create systems that can be functionalized for specific tasks including drug delivery, materials templating, or catalysis; the colloidal interactions often define properties such as rheology and product stability. This project addresses the science and engineering needed to advance the formulation of polyelectrolytes and surfactants, and combines the resources of an academic laboratory with those of the dominant US industrial laboratory in this field.The basic theme is experimental study of mixtures of polyelectrolyte with either same or oppositely charged surfactants, with two specific aims: 1. Investigate the microstructure and phase behavior of mixtures of mechanically-formed vesicles made from insoluble surfactants (R ~ 15 nm) and same-charged polyelectrolyte (Rg ~ 100 nm), in what is often referred to as the nano-particle limit (i.e., Rg R). Emphasis will be on understanding the role polymer characteristics such as flexibility and inter-polymer interactions (e.g., virial coefficients and specific surfactant-polymer interactions) play in the colloidal-scale structure of these mixtures. There is particular interest in the dilute and semidilute polymer concentration regime, which can be interpreted in the context of the Polymer Reference Interaction Site Model (PRISM), as well as in concentrated regimes that reflectpractical product formulations. 2. Investigate in a methodical and systematic way the interactions of polyelectrolyte and soluble surfactants. With one exception, the project will focus on the study of weak polyelectrolyte (in which the charge groups are weak acids or bases). Features to be explored include binding isotherms, the molecular features of the polyelectrolyte (charge density, backbone rigidity, and molecular weight), configurations of polymer/surfactant aggregates, and the characteristics of resulting gel phases and aggregates. Of particular interest will be documentation of the competition between cationic polymer and cationic surfactant for association with anionic surfactant, and the role of hydrotropes. While these specific aims reflect specific industry needs, this work should also provide a set of rational design rules relevant to all nano-material formulations.Intellectual Merit: The experimental results of the project will provide a motivation for extension and development of PRISM-like theories, while at the same time providing empirical rules for product design. The tandem of cryo-visualization and scattering willprovide new insights into the binding and organization of soluble polyelectrolyte/surfactant complexes heretofore not available for weak polyelectrolytes, and the systematic phase and structure work will enable observation of new patterns. Broader Technical Impact: The commercial value of this work is potentially enormous, with surfactant/polymer industries generating multi-billion dollars in revenue per annum. The scientific aspects of this proposed work will enable discovery of new patterns of colloidal stability and microstructure evolution. This will be significant for both Procter & Gamble as well as the broader colloid community. Broader Social Impact: Undergraduate and graduate students involved in this work will be exposed to a range of characterization tools in preparation for either academic or industrial work. Visualization studies by electron microscopy are especially appealing to K-12 students, who will be exposed to concepts relevant to this work, including surfactant and polymer properties and elements of nanotechnology.

纳米级聚电解质与表面活性剂的自组装成为结构复杂的流体是许多当代科学和商业努力的核心。它是特种化工行业的一个主要重点，并使个人护理产品得以进步。同样的化学和物理也支配着生物系统中的非特异性相互作用，并在蛋白质和其他药物的下游提纯和配方中发挥重要作用。尽管这些混合物显然很重要，但在理解聚电解质和表面活性剂如何相互作用以形成特定的微结构和决定胶体尺度性质方面仍存在重大差距。这些结构通常是纳米级的，用于创建可用于特定任务的功能化系统，包括药物输送、材料模板或催化；胶体相互作用通常定义诸如流变学和产品稳定性等性质。本项目致力于发展聚电解质和表面活性剂配方所需的科学和工程，并结合该领域的学术实验室和美国主要工业实验室的资源。基本主题是聚电解质与相同或相反电荷的表面活性剂的混合物的实验研究，具体目的有两个：1.研究由不溶性表面活性剂(R~15 nm)和相同电荷的聚电解质(Rg~100 nm)制成的机械形成的囊泡的微观结构和相行为，在通常被称为纳米粒子极限(即Rg R)的范围内。重点是了解聚合物的特性，如柔韧性和聚合物间的相互作用(例如，维里系数和特定的表面活性剂-聚合物相互作用)在这些混合物的胶体尺度结构中所起的作用。人们对稀释和半稀释聚合物浓缩制度特别感兴趣，这可以在聚合物参考相互作用部位模型(PRISM)的背景下解释，以及在反映实际产品配方的浓缩制度中解释。2.系统、系统地研究了聚电解质与可溶性表面活性剂的相互作用。除了一个例外，该项目将专注于弱聚电解质(其中电荷基团是弱酸或弱碱)的研究。待探索的特征包括结合等温线、聚电解质的分子特征(电荷密度、主链刚性和分子质量)、聚合物/表面活性剂聚集体的构型以及所产生的凝胶相和聚集体的特征。特别感兴趣的是记录阳离子聚合物和阳离子表面活性剂与阴离子表面活性剂之间的竞争，以及亲水物质的作用。虽然这些特定的目标反映了特定的行业需求，但这项工作也应该提供一套适用于所有纳米材料配方的合理设计规则。智力优势：该项目的实验结果将为类似棱镜的理论的推广和发展提供动力，同时为产品设计提供经验规则。冷冻显影和散射的串联将提供对迄今不适用于弱聚电解质的可溶性聚电解质/表面活性剂络合物的结合和组织的新见解，系统的相和结构工作将使观察到新的模式成为可能。更广泛的技术影响：这项工作的商业价值潜在巨大，表面活性剂/聚合物行业每年产生数十亿美元的收入。这项拟议工作的科学方面将使发现胶体稳定性和微观结构演变的新模式成为可能。这对宝洁和更广泛的胶体群体都将具有重大意义。更广泛的社会影响：参与这项工作的本科生和研究生将接触到一系列表征工具，为学术或工业工作做准备。电子显微镜的可视化研究对K-12年级的学生特别有吸引力，他们将接触到与这项工作相关的概念，包括表面活性剂和聚合物的性质以及纳米技术的元素。