Specific Interactions in Polymer Systems

这项研究涉及对聚合物体系中特定相互作用的研究。这项工作的一部分试图从根本上了解聚合物共混物中微观结构、相互作用、构象和相行为之间的相互作用。将全面研究立体规整性对官能团氢键能力的影响。还将通过合成和表征合适的共聚物来研究沿链间隔这些基团对这些基团可及性的影响。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变和驰豫过程的影响。人们普遍认为，红外谱带和拉曼线的形状蕴藏着丰富的分子动力学信息。将通过系统的实验研究来评估从聚合物光谱中获得有关皮秒动力学的有用信息的程度。聚合物共混物的相行为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。因此，了解相互作用在制造可混溶或相容共混物中的作用，这是本研究的重点，对新材料的开发非常重要。这项研究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NSF奖项所支持的工作产生了基于CD的专著，包括动画和互动程序，将扩展到涵盖氢键和聚合物混合物的热力学。

This research involves studies of specific interactions in polymer systems. One part of the work seeks to obtain a fundamental understanding of the interplay between microstructure, interactions, conformation and phase behavior in polymer blends. A comprehensive study the effect of stereoregularity on the ability of functional groups to hydrogen bond will be performed. The effect of spacing these groups along the chain on the accessibility of these groups will also be investigated through the synthesis and characterization of appropriate copolymers. 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 phase changes and relaxation processes. It is widely recognized that a wealth of information on molecular dynamics lies buried in the shapes of infrared bands and Raman lines. The extent to which useful information on picosecond dynamics can be obtained from the spectra of polymers will be evaluated by means of a systematic experimental study. %%%The phase behavior of polymer blends 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. Accordingly, understanding the role of interactions in making miscible or compatible blends, the focus of this research, is important in the development of new materials. This research 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 cover hydrogen bonding and the thermodynamics of polymer mixtures.***