Polymorphism, Metastability and Structure in Conjugated Polymers

导电聚合物表现出各种有趣的、具有重要技术意义的物理行为。在理想的情况下，沿着导电聚合物骨架的电荷传输的准一维方面为研究低维物理创造了一个有趣的环境。现实情况是，这些材料本质上是聚合的，并表现出广泛的、有时令人困惑的属性阵列，这些属性与存在于分子长度尺度上的结构-性质关系密切相关。随着越来越复杂的体系结构和处理步骤的出现，继续需要更好地了解主要的潜在关系，并确定关键的结构属性和相关的结构演变。这项研究代表了开发实验方法的持续努力，这些方法使得能够直接和定量地测量PI和Sigma共轭聚合物的局部结构有序性，无论它们是结晶、半结晶和/或非晶态的。将同时使用X射线和中子散射技术。在有利的情况下，可以用反常散射技术和光学光谱学来补充传统的散射方法。这些实验研究将进一步得到模拟计算的补充，这些计算产生典型的分子结构。这样，就有可能更全面地评估当地结构环境的性质。除了这些举措外，还将开发研究原位结构演化的方法，以便能够识别和分析微妙的和瞬时的影响。%通过本研究过程开发的知识和技术将为导电聚合物主体内的结构及其演化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.***