Synergistic or Antagonistic Effects of Polymer/Surfactant Supramolecular Assembly on the Colloidal Depletion Force

CBET -1608003 PI：Tilton，Robert当微观“胶体”颗粒悬浮在含有聚合物的溶液中时，聚合物往往被排除在颗粒之间的间隙之外。这种排斥产生了一种称为耗尽力的力，它可以将颗粒吸引到一起形成聚集体。 一些工业过程通过促进污染物颗粒的聚集以将它们从溶液中去除来利用消耗力。 然而，在成分必须保持在溶液中的其他工艺中，例如油漆颜料颗粒或药物中的活性剂，消耗力可能是不期望的。这种液体产品必须配制成防止消耗诱导的聚集。当离子表面活性剂也存在于聚合物溶液中时，它们可以与聚合物结合并以不完全理解的方式改变耗尽力。该项目将研究各种聚合物/表面活性剂混合物，以更好地了解聚合物-表面活性剂结合如何影响悬浮液的消耗力和稳定性。胶体探针原子力显微镜将用于测量聚合物/表面活性剂混合物中的耗尽力。该项目的结果将对制造和加工胶体流体的工程师有用，包括油漆，涂料，局部药物和个人护理产品。该项目将为不同学术水平的学生提供研究机会，包括通过设计实验来检查液体产品配方的物理化学来参加大学物理概念课程的中学生。本项目将研究聚合物/表面活性剂络合对胶体悬浮液中消耗力的作用。聚合物/表面活性剂混合物中的胶体力将通过胶体探针原子力显微镜测量。该项目将揭示离子表面活性剂与非离子聚合物或带相反电荷的聚电解质之间的络合如何放大或抑制耗尽力。实验数据将解释的模型，预测耗尽力的基础上聚合物/表面活性剂复合物的化学计量，电荷和大小。结果将与胶体稳定性相图的一系列系统，代表典型的聚合物/表面活性剂缔合行为的类别。该项目的成果将有利于工业实践，其中络合用于多组分液体混合物，以产生新的材料性能和产品，减少对环境的影响。

CBET - 1608003PI: Tilton, RobertWhen microscopic "colloidal" particles are suspended in a solution containing polymers, the polymers tend to be excluded from the gaps between particles. This exclusion gives rise to a force called the depletion force, which can draw particles together to form aggregates. Some industrial processes take advantage of the depletion force by promoting aggregation of contaminant particles to remove them from solution. However, the depletion force may be undesirable in other processes where ingredients must remain in solution, such as paint pigment particles or active agents in pharmaceuticals. Such liquid products must be formulated to prevent depletion-induced aggregation. When ionic surfactants are also present in the polymer solution, they can bind to the polymers and alter the depletion force in ways that are not completely understood. This project will examine various kinds of polymer/surfactant mixtures to better understand how polymer-surfactant binding influences the depletion force and the stability of the suspension. A colloidal probe atomic force microscope will be used to measure the depletion force in the polymer/surfactant mixtures. The results of the project will be useful to engineers who manufacture and process colloidal fluids, including paints, coatings, topical medications, and personal care products. The project will provide research opportunities for students at various academic levels, including middle school students who participate in the university's Physics Concepts Programs by designing experiments to examine the physical chemistry of liquid product formulations. This project will examine the role of polymer/surfactant complexation on depletion forces in colloidal suspensions. Colloidal forces in polymer/surfactant mixtures will be measured by colloidal probe atomic force microscopy. The project will reveal how complexation between ionic surfactants and either nonionic polymers or oppositely charged polyelectrolytes can amplify or suppress depletion forces. Experimental data will be interpreted in terms of a model that predicts depletion forces based on polymer/surfactant complex stoichiometry, charge and size. Results will be correlated with colloidal stability phase diagrams for a series of systems that represent canonical categories of polymer/surfactant association behavior. The outcomes of the project will benefit industrial practice where complexation is used in multicomponent liquid mixtures to produce novel material properties and products with diminished environmental impacts.