Polymorphism, Metastability and Structure in Conjugated Polymers

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

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. ***