Specific Interactions In Polymer Systems

技术总结本研究涉及对聚合物体系中特定相互作用的研究。拟议工作的一部分试图从根本上了解氢键聚合物共混物中微结构和同链接触或自浓缩的比例之间的相互作用。对这些混合物中氢键基团比例的测量也将被用来确定氢键对流变性的影响。这项工作将得到拟议研究的第二部分的补充，该部分涉及研究这些强相互作用系统中带的形状和宽度，以及这些形状和宽度如何受到相互作用和弛豫过程的影响。红外波段和拉曼线对局域环境和皮秒尺度的动力学非常敏感。通过将谱带形状分析的结果与应用超快二维红外光谱(2D-IR)技术获得的结果进行比较，将评估从聚合物的光谱中获得有用信息的程度。非技术总结控制聚合物材料混合和所谓的松弛现象(控制其机械和流变行为)的因素具有相当重要的实际意义。寻找在分子水平上混合的聚合物(大多数不是)可以产生具有新性能的材料。即使是相分离的聚合物也可以具有重要的性能，例如增强的抗冲击性，前提是相分离结构域的大小得到控制。这项研究将使用红外光谱来研究聚合物及其混合物中的特定相互作用和松弛行为。这项工作还将通过让本科生和研究生参与实验室工作的机制来促进教育，从而向他们传授光谱和其他技术的基础知识。更独特的是，以前的NSF奖项所支持的工作产生了基于CD的专著，并配有动画和互动程序，将扩大到制作可在网络上免费访问的讲座集。

TECHNICAL SUMMARYThis research involves studies of specific interactions in polymer systems. One part of the proposed work seeks to obtain a fundamental understanding of the interplay between microstructure and the fraction of same chain contacts, or self-concentration, in hydrogen bonded polymer blends. Measurements of the fraction of hydrogen-bonded groups in these mixtures will also be used to determine the effect of hydrogen bonding on rheological properties. This work will be complemented by the second part of the proposed research, which involves studies of the shapes and widths of bands in these strongly interacting systems and how these are affected by interactions and relaxation processes. Infrared bands and Raman lines are sensitive to local environment and picosecond scale dynamics. The extent to which useful information can be obtained from the spectra of polymers will be evaluated by comparing the results of band shape analysis to those obtained by applying ultrafast two-dimensional infrared spectroscopic (2D-IR) techniques. NON-TECHNICAL SUMMARYThe factors that govern both the mixing of polymer materials and so-called relaxation phenomena (which govern their mechanical and rheological behavior) is of considerable practical importance. Finding polymers that mix at the molecular level (most do not) can lead to materials with novel properties. Even polymers that phase-separate can have important properties, such as enhanced impact resistance, providing that the size of the phase separated domains are controlled. This research will use infrared spectroscopy to study both specific interactions and relaxation behavior in polymers and their mixtures. The work will also contribute to education through the mechanism of involving both undergraduate and graduate students in laboratory work, thus teaching them the fundamentals of spectroscopic and other techniques. More uniquely, work supported on previous NSF awards that resulted in CD based monographs, complete with animations and interactive programs, will be extended to produce sets of lectures that will be freely accessible over the web.