Variation of Thermal and Optoelectronic Properties Through Compositional Control of Thiophene-Containing Statistical Copolymers

Conductive polymers are of widespread interest for application to organic-based electronics such as solar panels, thermoelectric generators, and chemical sensors. Polyalkylthiophenes are an important subclass of conjugated polymers that are widely-studied due to their well-controlled synthesis and favorable optoelectronic and solid-state properties. It is known that small changes to the microstructure of 3-substituted polythiophenes can greatly impact material properties, yet a complete understanding of structure-property relationships has remained elusive. By systematically synthesizing a series of statistical copolymers of 3-alkylthiophenes with thiophene, a more complete understanding of the structure-property relationship can be gained. In particular, we synthesize copolymers of 3-hexylthiophene and thiophene of varied comonomer compositions and investigate the resulting material properties. Copolymer molecular weight and dispersity are characterized via 1H NMR spectroscopy and gel-permeation chromatography respectively, the optical absorbance and optical band gaps are characterized with UV/Vis spectroscopy and the Spano Model, and the solid-state properties are evaluated using differential scanning calorimetry and thermogravimetric analysis.