GOALI: "Dynamically Responsive Polymeric Additives for Process Improvements an Environmental Compability"

CTS-9817048该计划旨在为聚合物添加剂的定制设计制定规则，这将使几个工业部门更接近环境兼容性：涂料配方（用水性配方代替有机配方）、废水处理（对强曝气低固体污泥有效的絮凝剂）、造纸（增加白水循环和降低废物流体积）、水性润滑和采油（与砂岩地层相容的可生物降解添加剂）。在这些情况下，环境相容取决于对聚合物吸附和胶体现象的瞬态动力学方面的基本理解。特别是，该程序针对特定聚合物化学和结构如何决定(1)吸附速率和(2)界面松弛的问题。然后，该程序解决了(3)在不同松弛阶段的吸附层如何介导胶体相互作用并引起稳定或絮凝。这个程序的结果，除了允许人们定制对特定过程的时间尺度动态响应的分子的设计规则之外，还包括关于瞬态胶体势的信息，这将促进特定过程的絮凝和稳定模型。利哈伊的核心科学项目辅以涉及4家公司的联络项目、合作项目和5年硕士课程，以最有效的技术转移，将基础知识带到具体的工业情况。采用模型窄分子标准水溶性聚合物（聚乙烯氧化物和基于普鲁兰的聚合物）和受控化学底物（通过沉积自组装单层）的实验程序将允许在吸附、界面松弛和界面胶体演化研究中相关化学和结构参数的系统变化。这些模型系统的使用对动力学行为理论的发展至关重要。吸附，松弛和胶体力的问题将通过独特的技术组合进行探讨。聚合物吸附和弛豫动力学将通过全内反射荧光（TIRF）和近布鲁斯特反射率的协同组合来测量，这是在国家科学基金会的支持下由PI实验室开发的。这两种方法一起测量不断变化的表面质量，不断变化的层厚度和密度，以及荧光标记的界面种群的动力学行为。界面弛豫将通过TIRF自交换研究进一步探讨。这些研究将建立层的演化时间尺度，并提供哪些层的特征演化的一些想法。根据研究启动奖开发的模型将被修改，以对观察到的动力学给出定量解释。下一阶段的工作将这种不断发展的层结构与胶体行为联系起来。胶体力的动态测量将使用“MASIF”进行测量，类似于表面力装置，但专为动态数据采集而设计。最后，撞击射流胶体沉积研究将用于测量界面松弛和成对胶体力测量如何在强剪切和水动力碰撞力的情况下转化为絮凝或稳定。黏附能力作为瞬态界面状态和水动力条件的函数，可用于现有絮凝模型，使其更适合废水、纸张、涂料和采油等应用。

ABSTRACT CTS-9817048 Santore, Maria/Lehigh U. This program targets the generation of rules for the custom design of polymeric additives that will bring several industrial sectors closer to environmental compatibility: coatings formulation (replacement of organic formulations with aqueous ones), waste water treatment (flocculants effective for aggressively aerated low solids sludges), paper making (increased white water recycle and lower waste stream volume), aqueous lubrication, and oil recovery (biodegradable additives compatible with sandstone formations). In these instances environmental compatibilization depends on a fundamental understanding of the transient dynamic aspects of polymer adsorption and colloidal phenomena. In particular, the program targets the questions of how specific polymer chemistry and architecture determine (1) adsorption rates and (2) interfacial relaxations. The program then addresses (3) how adsorbed layers in different stages of relaxation mediate colloidal interactions and cause stabilization or flocculation. The outcome from this program, in addition to design rules that allow one to tailor molecules that are dynamically responsive to the timescales of particular processes, includes information about transient colloidal potentials that will facilitate process-specific flocculation and stabilization models. The core scientific program at Lehigh is supplemented with liaison projects involving 4 companies, coop programs, and 5th year masters programs, for the most effective technology transfer to bring the fundamentals to the specific industrial situations. An experimental program employing model narrow molecular standard water soluble polymers (polyethylene oxide and pullulan - based) and substrates of controlled chemistry (through the deposition of self assembled monolayers) will allow systematic variations in the relevant chemical and architectural parameters in studies of adsorption, interfacial relaxation, and the evolution interfacial colloidal for ces. Use of these model systems is critical to the development of theory for dynamic behavior. The issues of adsorption, relaxation, and colloidal forces will be probed through a unique combination of techniques. Polymer adsorption and relaxation kinetics will be measured with a synergistic combination of total internal reflectance fluorescence (TIRF) and near-Brewster reflectivity, developed in the PI's lab under prior NSF support. Together the two methods measure the evolving surface mass, the evolving layer thickness and density, and the kinetic behavior of fluorescently-tagged interfacial populations. Interfacial relaxations will be further probed through self exchange studies using TIRF. These studies will establish the evolutionary timescales of the layers and provide some idea of which layer features evolve. Models developed under a Research Initiation Award will be modified to give quantitative explanation of the observed dynamics. The next phase of work relates this evolving layer structure to colloidal behavior. Dynamic measurements of colloidal forces will be measured using 'MASIF," similar to the surface forces apparatus, but designed for dynamic data acquisition. Finally impinging jet colloidal deposition studies will be employed to measure how interfacial relaxations and pairwise colloidal force measurements translate to flocculation or stabilization in situations of strong shear and hydrodynamic collision forces. The sticking ability, as a function of the transient interfacial state and hydrodynamic conditions can be used in existing flocculation models to make them more process-specific for wastewater, paper, coatings, and oil recovery applications.