Subtle structural changes in monomeric building blocks serve as a synthetic handle to manipulate the perceived color of conjugated polymers that find applicability in electrochromism. With this in mind, it is paramount to understand the influence of minimal structural alterations, such as isomeric effects, that manipulate optical and electrochemical characteristics. Herein, a family of dialkylthiophene-co-3,4-propylenedioxythiophene (ProDOT) copolymers are synthesized via direct arylation polymerizations, with a key design motif being minimal changes in the structural composition of the ProDOT comonomer. Variation in the substitution pattern on the propylene bridge provides insight into the role of stereo- and compositional isomers on the resulting polymer properties. Specifically, time-dependent density functional theory calculations reveal changes in the number and placement of comonomers with varying composition and stereocenters impacting the calculated absorbance spectra, which ultimately manifests in differences in the calculated color. Experimentally, UV-vis absorbance spectroscopy and colorimetry reveal a dependence on the stereo- and regiospecificity, while electrochromic properties, such as contrast and switching times, are not drastically affected by the substitution patterns. This work highlights how subtle structural changes can manipulate and  be used to optimize optical features without sacrificing electrochromic properties. In addition to fundamental insights into monomeric design of ProDOT building blocks and their optical and redox characteristics, the results provide an additional structural handle for fine-tuning the observed color of electrochromic polymers.

Exploring isomeric effects on optical and electrochemical properties of red/orange electrochromic polymers

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.