Title

Conducting polymers from processable precursors and their applications to gold surfaces

Date of Completion

January 2007

Keywords

Chemistry, Polymer

Degree

Ph.D.

Abstract

Processability remains to be a significant hurdle towards the implementation of insoluble and infusible conducting polymers, which are synthesized by either chemical (e.g. Lewis acid catalyzed via chemical oxidant (FeCl3)) or electrochemical methods. Despite providing facile control in electrochemical route, relatively poor yields have obviated electrochemical polymerization from being implemented on the industrial scale. Here, we have developed two precursor routes that involve solid-state oxidative conversion to address the processing of solid forms of conductive polymers. The first route to CPs was realized using tethered bis(3,4-ethylenedioxythiophene)thiophene (BEDOT-T) and bis(3,4-ethylenedioxythiophene)benzene (BEDOT-B) off poly(norbornylene) via Ring Opening Methathesis Polymerization (ROMP). Solid-state oxidative conversion of these poly(norbornylene) backbones with pendant monomers provides a crosslinked conductive network. The second route involves the oxidative cleavage of silane units that are bound within a polymeric precursor backbone containing conjugated BEDOT-B and BEDOT-T monomers. The solid-state oxidative conversion process involves the "unzipping" of the precursor and the "zipping" of the conjugated conductive polymer to provide a linear polymer. ^ There has been significant interest in developing methods to prepare polymer functionalized gold nanoparticles (AuNPs) and surfaces. Herein, we report the use of surface-initiated ROMP for the preparation of BEDOT-T containing polynorbornylene brushes on the gold surface and AuNPs, and their solid-state oxidative conversion to conductive polymer networks. These polymer brushes have been microscopically, electrochemically and spectroscopically characterized. Reversibly tunable surface plasmon band of the gold nanoparticles is achieved by electrochemically switching between reduced and oxidized states of the conjugated polymer networks. ^