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.