GOALI: Colloid Stability and Transport in Solutions of Nonadsorbing Polyelectrolytes

abstractcts - 9912098 j。提出的努力是探索非吸附聚电解质对带电粒子分散稳定性的影响。这些知识的应用将是多方面的。例如，不吸附的聚电解质的存在可以增强场流的分馏。本研究的核心是确定粒子间力（与静电和范德华力相比），因为它们控制着聚丙烯-胶体体系的稳定性。研究方向如下：1)提高聚电解质浓度对絮凝现象的影响，在某些情况下，絮凝后再稳定。一个模型有望能够解释实验测量的全面范围。2)多分散性和电荷非均质性将与现有的种间力平衡相关。该模型将在光学技术（如全内反射显微镜）的帮助下建立。3)将特别关注一个重要的工业过程，即氧化钛颗粒与各种稳定剂的相互作用。特别是，表面粒子的力分布将用原子力显微镜来确定。絮凝率将通过声谱法得到。4)棒状几何在粒子相互作用中的作用将被研究。验证将在特征良好的DNA片段上进行测试。5)非吸附聚电解质对表面附近颗粒输运过程的影响将进行测试和建模。多孔介质内或多孔介质附近的流场对工业设计具有重要意义。

AbstractCTS-9912098J. Walz, Yale UniversityThe proposed effort is to explore the effect of nonadsorbing polyelectrolytes on the stability of a dispersion of charged particles. The application of this knowledge would be many. For instance, the fractionation of field flows could be enhanced by the presence of nonadsorbing polyelectrolytes. Central to this study is the determination of interparticle forces (as compared to electrostatic and van der Waals), as they control the stability of polyelctrolyte-colloid systems. Several directions would be investigated:1) The influence of increased polyelectrolyte concentration on the appearance of flocculation followed, in some cases, by restabilization. A model will hopefully be able to account for a comprehensive range of experimental measurements.2) Polydispersity and charge heterogeneity will be correlated with the existing interparticular force balance. This modeling will be established with the help of optical techniques (e.g. total internal reflection microscopy).3) Special attention will be given to an important industrial process, viz. the interaction of titanium oxyde particles with various types of stabilizers. In particular, surface-particle force profiles will be determined with an atomic force microscope. Flocculation rates will be obtained by acoustic spectrometric methods.4) The role of rod-like geometry in particle interaction will be investigated. Validation will be tested on well-characterized DNA segments.5) The effect of nonadsorbing polyelectrolytes on particle transport processes in the vicinity of surfaces will be tested and modeled. Flow fields in or near porous media is of fundamental interest to industrial design.