Impact of Side Chain Polarity and Symmetry on the Structure and Properties of Acyclic Dioxythiophene Polymers

Published

June 20, 2025

Author(s)

Rinehart Joshua, Zhuang Xu, Anna Österholm, Lucas Flagg, Lee Richter, Shannon Yee, Ying Diao, John Reynolds

Abstract

Conjugated polymer side chains promote solution processability, but also play a crucial role in solution aggregation, solid-state ordering, and determining polymer-electrolyte interactions. Side chains can heavily influence the repeat unit symmetry, polarity, steric bulkiness, and non-covalent interactions that often dictate how polymer chains pack and assemble. A useful structure for redox-active organic mixed ion-electron conductors are acyclic dioxythiophene polymers (PAcDOTs), which have two alkoxy side chains (R1 and R2) directly appended to the thiophene unit. Changing the AcDOT side chain to be symmetric, unsymmetric, non-polar, or amphiphilic had a profound impact on solution and solid-state structures. In this study, a family of PAcDOTs with either non-polar or amphiphilic side chains were designed to control regio-symmetry of the polymer repeat unit. Regio-symmetric PAcDOTs displayed thermotropic liquid crystal phases, while only the amphiphilic, regio-symmetric polymer formed a chiral, lyotropic phase in chloroform solutions. Temperature dependent grazing incidence x-ray scattering and cross-polarized optical microscopy were used to investigate how the solid-state morphology evolved during thermal annealing. The impact of side chain polarity, symmetry, and film annealing significantly affected the achievable optical contrast during electrochemical cycling and electrochemical switching kinetics between the colored, neutral and colorless, doped state.

Citation

(potentially a different journal, still TBD)

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.chemmater.4c03394

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Keywords

Thiophene polymer, x-ray scattering, liquid crystallinity, redox active polymers

Citation

Joshua, R. , Xu, Z. , Österholm, A. , Flagg, L. , Richter, L. , Yee, S. , Diao, Y. and Reynolds, J. (2025), Impact of Side Chain Polarity and Symmetry on the Structure and Properties of Acyclic Dioxythiophene Polymers, (potentially a different journal, still TBD), [online], https://doi.org/10.1021/acs.chemmater.4c03394, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=958726 (Accessed December 11, 2025)