With the discovery of near metallic conductivity in films of polyacetylene in the late 1970s, the field of “Conducting Polymers” was initiated.  After further development to polypyrroles, polyanilines, and the ultimate development of PEDOT/PSS as a commercial material, extension of work into semiconducting properties for light emission, photovoltaic light harvesting, transport for field effect transistors became dominant.  All the while, redox doping remained important to many applications including charge storage (batteries and supercapacitors), chemical/bio sensing, and electrochromism.  With the advent of more mature conjugated polymer structures, has come solubility for effective processing and printing, along with controlled oxidation and reduction potentials needed for stable, charged and conducting materials.  In this presentation, we detail synthetic developments in the preparation of dioxythiophene-based polymers and copolymers using direct heteroarylation polymerization methods to yield low-oxidation potential polymers that are easily doped to highly electrically conducting states.  Combining 3,4-propylenedioxythiophene (ProDOT) monomers disubstituted at the 2-position of the propylene bridge with nonpolar (e.g. alkyl) and polar (e.g. ester, oligoether, etc.) substituents, we control solubility to allow environmentally-benign solvent processing.  Copolymerization of these functional ProDOTs with dimethyl ProDOT, EDOT, and biEDOT provide increasingly electron rich conjugated backbones which, upon careful oxidative doping, reach conductivities up to 250 – 400 S/cm.  Potential-dependent conductivity profiles are monitored in situ to determine the breadth of the windows of high conductivity.  Using chemically cleavable side chains, the electroactive fraction of the conjugated polymer is increased and has yielded doped compositions with conductivities in excess of 450 S/cm.  These high and reversibly switchable conductivities provide opportunities for new thermoelectric materials, switches for flexible/printable circuits, and controlled modulation of infrared absorption.

Putting “conductivity” back into conducting polymer research

ACS Spring Meeting 2021

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