(653c) Structure-Processing-Property Relationships of 3-Hexylthiophene-Containing Statistical Copolymers

As the strain on the energy generation sector of the U.S.A. continues to increase, the need for enhanced energy recovery devices also grows. Conductive polymers such as polythiophene and its derivatives present the opportunity to realize devices with tunable properties to aid in the recovery of the wasted heat from the generation sector. Copolymers containing 3-hexylthiophene have been widely studied for this application due to their well-controlled synthesis and favorable optoelectronic and solid-state properties. It is well known that small changes to polythiophene microstructure, either by 3-position substitution or by copolymerization of thiophene derivatives, yields polymers with tunable properties and favorable combinations of homopolymer properties to enhance resulting device performance. In this work we synthesize a broad range of statistical copolymers composed of 3-hexylthiophene and other various thiophene derivatives. Properties such as monomer reactivity ratios and the resulting copolymer regioregularities are characterized via ¹H NMR spectroscopy. Relative molecular weight and dispersity are characterized with gel-permeation chromatography. Crystallization behavior, thermal properties, and crystal structures are determined via differential scanning calorimetry and thin-film X-ray diffraction. The optoelectronic properties such as optical absorbance and optical band gap are determined using UV/Vis spectroscopy with the Spano Model. This work provides insights into the microstructure-property-processing relationship of polythiophene and its derivatives.