Polymorphism, Metastability and Structure in Conjugated Polymers

导电聚合物表现出多种多样的有趣的和技术上重要的物理行为。 在理想化的环境中，电荷沿沿着导电聚合物骨架的准一维输运为研究低维物理创造了一个有趣的环境。 事实上，这些材料本质上是聚合物，并且表现出广泛的，有时令人困惑的属性，这些属性与分子长度尺度上存在的结构-性质关系密切相关。 随着越来越复杂的结构和处理步骤的出现，持续需要更好地理解主要的潜在关系，并确定关键的结构属性和相关的结构演变。这项研究代表了一个持续的努力，利用实验方法，使直接和定量测量的局部结构顺序的π和σ共轭聚合物，无论它们是结晶，半结晶和/或无定形。 将利用X射线和中子散射技术。 在有利的情况下，常规散射方法可以通过异常散射技术和光谱学来补充。 这些实验研究将通过生成代表性分子结构的建模计算来进一步补充。 这样，就有可能更全面地评估当地结构环境的性质。 除了这些措施外，还将开发研究现场结构演变的方法，以便识别和分析细微的瞬态效应。通过本研究过程开发的知识和技术将为导电聚合物主体的结构及其演变提供基本和准确的答案。

Conducting polymers exhibit an enormous diversity of interesting and technologically important physical behavior. In an idealized setting the quasi-one-dimensional aspects of charge transport along the conducting polymer skeleton create an intriguing environment for studying low-dimensional physics. The reality is that these materials are polymeric in nature and exhibit a wide, and sometimes bewildering, array of attributes which are intimately tied to structure-property relationships that exist at molecular length scales. With the advent of increasingly more complex architectures and processing steps there is a continuing need to better understand the main underlying relationships and to identify the key structural attributes and the associated structural evolution. This research represents a continuing effort to exploit experimental methods which enable direct and quantitative measures of the local structural order in pi and sigma-conjugated polymers whether they are crystalline, semi-crystalline and/or amorphous. Both x-ray and neutron scattering techniques will be utilized. When advantageous, conventional scattering methods can be supplemented by anomalous scattering techniques and optical spectroscopy. These experimental studies will be further complemented by modeling calculations which generate representative molecular structures. In this way, it will be possible to more completely assess the nature of the local structural environment. In addition to these initiatives, methods will be developed for studying the evolution of structure in situ so that subtle and transient effects can be discerned and analyzed.%%%The knowledge and techniques developed through the course of this research will provide basic and accurate answers of structure and its evolution within conducting polymer hosts.***