Effect of Ions on Polymer Properties: Perfluorinated Ionomers, Model Compounds and Ionomer Blends

拟议研究的目的是研究离子基团对全氟离子单体膜、离子单体溶液和离子单体共混物的结构和动力学的影响。计划进行以下实验。首先，他们将研究被极性溶剂膨胀和溶解的膜中聚合物链和反离子的动力学。在膜和溶液之间的过渡中，结构变化的可能性将从研究中推断为离聚体浓度的函数。实验研究将由链动力学的理论模型加以补充。其次，他们将评估基于质子化和氟化表面活性剂的反胶束体系在多大程度上可以用作更复杂的全氟化离聚体的模型化合物。第三，他们建议研究离子单体共混物中的段动力学和相结构，其中特定的相互作用有望改善共混物组分的混相性。我们建议从聚丙烯酸和随机和嵌段苯乙烯丙烯酸共聚物与聚（环氧乙烷）和聚（乙烯基吡咯烷酮）的共混开始。研究了不同的反离子对酸性基团逐渐中和的影响。第四，我们计划开发电子自旋共振（ESR）成像作为一种非破坏性的方法，用于离子和其他复杂聚合物体系中二维和三维的实时扩散过程研究。我们建议使用ESR（包括多频ESR、双共振和成像）方法来观察顺磁反离子和氘化报告分子，19F NMR来观察全氟链，2H NMR用于可视化氘化溶剂的动力学，DSC用于将宏观性质与从光谱测量中获得的局部信息联系起来。离聚物是两亲性聚合物，含有高达10%的离子基团。在有机聚合物中掺入离子基团是改变聚合物性能的重要方法。与没有离子的类似聚合物链相比，这些基团的存在导致聚合物中弹性模量、玻璃化转变温度Tg和各种客体的渗透率发生巨大变化。这些变化大多归因于离子聚体中相分离形态的形成，由电荷集中的离子域和主要包括有机主链的非极性域组成。本研究旨在阐明膜的结构。

The objectives of the proposed research is to study the effect of ionic groups on the structure and dynamics of perfluorinated ionomer membranes, ionomer solutions and ionomer blends. The following experiments are planned. FIRST, they will study the dynamics of the polymer chains and counter ions in membranes swollen by, and dissolved in, polar solvents. The possibility of a structural change in the transition between membranes and solutions will be deduced from studies as a function of ionomer concentration. The experimental studies will be complemented by theoretical modeling of the chain dynamics. SECOND, they will assess to what extend reverse micellar systems based on protonated and fluorinated surfactants can be used as model compounds for the more complex perfluorinated ionomers. THIRD, they propose to study segmental dynamics and phase structure in ionomer blends, where specific interactions are expected to improve the miscibility of the blend components. We propose to start with blends of polyacrylic acid and random and block styreneacrylic acid copolymers with poly(ethylene oxide) and with poly(vinyl pyrrolidone). The effect of gradual neutralization of the acid groups with various counter ions will be investigated. FOURTH, we plan to develop electron-spin-resonance (ESR) imaging as a non- destructive method for the study of diffusion processes in real time in ionomers and other complex polymeric systems, in two and three dimensions. We propose to use ESR (including multifrequency ESR, double resonance and imaging) methods for observing the paramagnetic counter ions and deuteriated reporter molecules, 19F NMR to observe the perfluorinated chains, 2H NMR to visualize the dynamics of deuteriated solvents and DSC to correlate the macroscopic properties with the local information obtained from the spectroscopic measurements. Ionomers are amphiphilic polymers that contain up to 10 mole percent of ionic groups. Incorporation of ionic groups in organic polymers is an important method for modifying polymer properties. The presence of these groups causes dramatic changes in the elastic modulus, glass transition temperature Tg and in the permeability of various guests in the polymers, compared to the analogous polymer chains without ions. Most of these changes have been attributed to the formation of a phase-separated morphology in ionomers, consisting of ionic domains where the charges are concentrated, and nonpolar domains that include mainly the organic backbone. This research aims to elucidate the membranes' structure.