Atomic-level order, disorder, and interactions in conjugated polymers and blends

Abstract

The properties of organic optoelectronic materials and devices depend on complicated compositional and structural features of conjugated polymers and intercalated guests that influence their mutual interactions and charge transfer properties. In particular, the presence, causes, and consequences of local order and disorder in such systems are generally subtle and have been challenging to establish. Nevertheless, advances in syntheses and characterization of heterogeneous polymeric materials increasingly enable atomic-level features to be measured and correlated with their macroscopic physicochemical properties. Solid-state NMR spectroscopy, especially two-dimensional techniques, provide improved resolution that yields detailed information on the local environments, interactions, and distributions of backbone, sidechain, and intercalated moieties in conjugated polymer materials and blends. In combination with X-ray scattering, molecular modelling, and macroscopic property measurements, the analyses yield insights on π-π interactions, backbone conformations, sidechain interdigitation, and their influences on structure-function relationships associated with organic photovoltaic or field-effect-transistor materials. Results and opportunities will be discussed for measuring and understanding the molecular interactions and distributions of compositional or structural order and disorder that influence the optoelectronic properties of conjugated polymer materials.

About the speaker

Professor Chmelka received his PhD in chemical engineering from the University of California, Berkeley in 1990 under the supervision of Prof. Clayton Radke and Prof. Eugene Petersen. Prior to graduate studies, he was a plant-startup engineer for two years with Unocal’s Oil Shale Operations in Colorado (U.S.), after receiving his Bachelors of Science degree in chemical engineering from Arizona State University. Following receipt of his PhD, he conducted post-doctoral research in at the University of California-Berkeley with Prof. Alexander Pines in the Department of Chemistry and at the Max-Planck-Institute for Polymer Research in Mainz, Germany with Prof. Hans Spiess.

Professor Chmelka joined the Department of Chemical Engineering at UCSB in 1992 and is currently Distinguished Professor. He is a foreign member of the Royal Swedish Academy of Sciences (2015) and the Royal Swedish Academy of Engineering (2017). His research has been recognized by the 2016 Braskem Award from the Materials Science and Engineering Division of the American Institute of Chemical Engineers, a David and Lucile Packard Foundation Award, a Camille and Henry Dreyfus Teacher-Scholar Award, an Alfred P. Sloan Foundation Research Award. He serves on several industrial and academic advisory boards and holds an honorary doctorate degree from Chalmers University of Technology in Sweden. He has been an invited professor at universities in Sweden, France, Spain, Israel, and Switzerland. Since 2015, he has served as Co-Director of the Institute for Collaborative Biotechnologies, a federally supported university affiliated research center involving research groups at UCSB, MIT, and Caltech. He has authored approximately 200 technical publications and 10 issued patents.