Interface-Induced Polyelectrolyte Structures

Schlenoff界面诱导的聚电解质结构已知界面有助于形成新颖有用的聚电解质结构。这些包括聚合物刷，用于稳定乳液和分散体。当具有寻找表面的端基或端块的聚合物暴露于固-液或液-固界面时，就会产生电刷。典型的电刷形成大分子包括聚电解质双嵌段共聚物，其中短疏水嵌段将聚合物从水溶液驱动到表面。由于分子的亲水、形成电刷的部分是聚电解质，电刷的构象将是反离子性质和浓度的强烈函数。由于电刷在稳定分散体时将暴露于各种离子中，因此确定这些离子对电刷吸附的影响至关重要。特别关注液/液界面-很少研究但非常普遍-刷子将在这里使用放射性标记的聚电解质生产。该标签允许准确的原位测定吸附在界面上的聚合物的量。使用一套最近开发的辐射测量技术，将在单价和二价反离子以及其他带电聚合物存在的情况下评估表面覆盖率。将解决的基本性质的问题包括聚合物是否以热力学可逆或不可逆（动力学限制）模式吸附。该项目还将重点研究由交替充电的聚电解质逐层沉积而成的超薄聚合物薄膜。这些新发现的聚电解质结构制备简单，在薄膜导体、发光层和生物活性（含酶）薄膜等方面具有潜在的应用前景。电荷在这些薄膜中平衡和分布的机制尚不清楚。在提出的工作中，多层膜内的电荷将使用放射性标记的反离子来探测。使用新型电化学活性聚电解质作为构建块，将建立具有一系列反离子浓度的多层膜的生产条件。这些多紫原将以新方法合成，并将测试其在电致变色和电催化薄膜上的应用。这个项目将增强我们对聚电解质多层、薄膜和界面的理解，这对胶体、粘附、润滑和表面科学具有重要意义。* * *

9727717 Schlenoff Interface-Induced Polyelectrolyte Structures Interfaces are known to assist in the formation of novel and useful polyelectrolyte structures. These include polymer brushes, whcih are employed in stabilizing emulsions and dispersions. A brush is produced when a polymer with a surface- seeking end group or block is exposed to a solid-liquid or liquid- solid interface. Typical brush-forming macromolecules include polyelectrolyte diblock copolymers, where a short hydrophobic block drives the polymer to the surface from aqueous solution. Since the hydrophilic, brush-forming segment of the molecules is a polyelectrolyte, the conformation of the brush will be a strong function of the nature and concentration of the counterion. Since brushes will be exposed to a variety of ions when they are applied to stabilizing dispersions, it is essential to determine the effect of these ions on brush adsorption. Focusing in particular on the liquid/liquid interface - rarely studied yet quite pervasive - brushes will be produced here using radiolabeled polyelectrolytes. The label permits accurate in situ determination of the amount of polymer adsorbed to the interface. Using a suite of recently-developed radiometric techniques, the surface coverage will be evaluated in the presence of monovalent and divalent counterions, as well as other charged polymers. Questions of a fundamental nature that will be addressed include whether the polymer is adsorbed in the thermodynamically reversible, or irreversible (kinetic limited) mode. This project will also focus on ultrathin polymer films made from the layer-by-layer deposition of alternately charged polyelectrolytes. These newly-discovered polyelectrolyte structures are straightforward to prepare and have potential applications as thin film conductors, light-emitting layers and bioactive (enzyme-containing) thin films. The mechanism by which charge is balanced and distributed within these films is not underst ood. In the proposed work, the charge within the multilayer films will be probed using radiolabeled counterions. Conditions for producing multilayers with a range of counterion concentrations will be established using novel electrochemically active polyelectrolytes as building blocks. These polyviologens will be synthesized by a new method and will be tested for application as electrochromic and electrocatalytic thin films. %%% This project will enhance our understanding of polyelectrolyte multilayers, thin films, and interfaces, which have important implications to colloids, adhesion, lubrication, and surface science. ***