BrianBeckinham “Structure-property relationships in polymer materials” Dr. Bryan S. Beckingham, Postdoctoral Fellow Lawrence Berkeley National Laboratory, Berkeley, CA

Tuesday, May 12, 2015 @ 1:30 PM (3147 MEB)

Polymer materials are ubiquitous in our daily lives and lie at the heart of many of today’s advanced technologies. A close inspection of our surroundings at any given time yields a wide variety of polymer materials that make life as we live it possible. Yet, there remains tremendous potential for improving our fundamental understanding of the interplay between polymer chemistry, polymer architecture and the resulting material properties and to thereby facilitate the design of new materials with tailored properties. One important polymer structural motif is copolymerization, or the polymerization of multiple monomers into the same polymer chain. Through precise control over the distribution of monomers along the polymer chain, a wide variety of polymer architectures (block, random, gradient etc.) can be achieved with consequently varying and tunable physical properties. This seminar will highlight how utilizing various copolymerization strategies can lead to fundamental insights into structure-property relationships in polymer materials. Polymer mixing thermodynamics will be discussed through the lens of microphase-separated block copolymers wherein one of the blocks is a random copolymer, so-called block-random copolymers. This polymer architecture facilitates the decoupling of the order-disorder transition temperature from the characteristic domain spacing of the phase-separated morphology. Additional discussion will focus on the relationships between solid-state structure—semi-crystallinity and crystal structure— and the optoelectronic properties of semiconducting poly(alkylthiophene)s. Namely, the ability to tune the crystallite size/perfection of poly(3-(2’-ethyl)hexylthiophene) through crystallization conditions and the relationships between copolymer composition in poly[(3-ethylhexylthiophene)-co-(3-(2’-ethyl)hexylthiophene)]s, their adopted crystal structure and resulting optoelectronic properties.