THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

will be held the

DISSERTATION THESIS DEFENSE

for

Joshua M. Rinehart

Advisors: Prof. John R. Reynolds and Prof. Shannon K. Yee
  
“To Cleave or Not to Cleave: Side-Chain Design in Dioxythiophene Polymers”

on

Wednesday, February 5, 2025

at 2:00 PM
in Manufacturing Related Disciplines Complex (MRDC) 4211
and via Teams:

Join the meeting now

  Committee Members:

Prof. John R. Reynolds, CHEM/MSE

Prof. Shannon K. Yee, ME

Prof. Mark Losego, MSE

Prof. Jason Azoulay, CHEM/MSE

Prof. Ying Diao (UIUC), ChBE/MSE

Abstract:

Conjugated polymers are often lightweight, flexible, biocompatible, conductors of both ions and electrons, and solution-processable, making them prime materials for a variety of unique applications. Conjugated polymer side-chains promote solution processability, but also play a crucial role in solution aggregation, solid-state ordering, and determining polymer-electrolyte interactions. This thesis explores side-chain design in dioxythiophene polymers, helping to decipher how polymer design, processing, and electrolyte impact polymer ordering and mixed ionic-electronic transport.

In this thesis defense, I will primarily describe the optimized synthesis of 3,4-propylenedioxythiophene polymers with side-chains that can be chemically removed post-processing. After solution printing, treatment of the films with a basic solution cleaves off the side-chains, resulting in a short alcohol or carboxylic acid functional groups capable of hydrogen-bonding. The mass and electronic transport during aqueous electrochemical doping for the polymers with alcohol or carboxylic acid groups is then compared to polymers with oligoether side-chains, which are more traditionally utilized. 

I will also briefly highlight other thesis work. The synthesis of acyclic dioxythiophene polymers has been improved and used to investigate how side-chain polarity and side-chain substitution symmetry influences solution aggregation and crystallization. A newly developed regio-symmetric, amphiphilic acyclic dioxythiophene polymer is used to study how electrolyte properties impact electrochemical doping and mixed ionic-electronic transport. A recently developed in situ electrochemical X-ray scattering technique is used to understand how the polymer microstructure evolves during electrochemical doping.