Structural Investigation of Electrically Conducting Polymer Composites for Organic Electronic Applications
Date of Completion
PEDOT:PSS, DNA, XRD, SEM, TEM, XPS
Field of Study
Doctor of Philosophy
The fundamental theme of this thesis is microstructure and electronic structure characterization on conducting polymers and biopolymers such as PEDOT:PSS, a polymer that consists of a conducting poly(3,4-ethylenedioxythiophene) polycation (PEDOT) and an insulating poly(styrenesulfonate) polyanion (PSS) and Deoxyribonucleic acid (DNA).
Beginning of the thesis will discuss the properties of DNA when cast from, Hexafluoroisopropanol (HFIP). HFIP was found to induce ordering in the orthogonal direction relative to the film surface in DNA-CTMA (CTMA-Cetyltrimethylammonium) when cast under very controlled conditions using HFIP. The ordering facilitated improved charge transport properties through the π-π base pair stacking within the DNA double helix. As a result, dielectric constant was increased by ~60% thereby improving the overall performance of varactors. In addition, when combined with low molecular weight poly(aniline) (PANI) film cast from the same “orthogonal alignment solvent” a miscible blend formed and resulted in a lower dielectric constant and higher dissipation factor as compared to DNA-CTMA cast from HFIP thereby making these properties tunable.
A separate study investigates PEDOT:PSS when introduced into commercial PET fabric containing silica nanoparticles. SEM, TEM, and XPS characterization revealed a possibly new mechanism for orders of magnitude improvement in current throughput, conductivity, and thermal properties. Microstructure and electronic structure was successfully reproduced including film formation and phase segregation between PEDOT and PSS. Charge transport properties revealed charge mobility, concentration, and conductivity was significantly higher as compared to PEDOT:PSS on commercial PET.
Santana, Jose L., "Structural Investigation of Electrically Conducting Polymer Composites for Organic Electronic Applications" (2015). Doctoral Dissertations. 679.