Date of Award

5-2008

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Chemistry

Advisor

Creager, Stephen

Abstract

In-situ electrochemical methods involving both oxidative and reductive mediators were employed to modify the oxidation state (doping level) of PEDOT polymers in colloidal PEDOT-coated silica core-shell particles that were prepared as a dispersion encapsulated in a hydrogel matrix. The modifications of the redox states of the PEDOT coating induced a change in the absorbance characteristics. A mediated electron transfer system was employed to ferry charge from the electrodes of the cell to the isolated particles. The mediator diffuses between the electrode surface and the PEDOT-coated particles to accomplish (de)doping. The developed system was a fully self-contained and electrically driven device. This allows for the electrochemical tuning of the optical properties of a crystalline colloidal array composed of these core-shell particles.
The synthesis of microstructured glassy carbon was done for possible use as an electrode for electrochemical biosensors and as a potential support for fuel-cell electrodes. Pyrolysis of the glassy carbon precursor poly-furfuryl alcohol (p-FA) was accomplished after polymerization of the precursor in the free space of highly developed porous silica monoliths that was similar to those used for high performance liquid chromatography (HPLC) columns. The porous silica monoliths were formed from the self-assembly of a sol-gel. The subsequent removal of the template material by hydrofluoric acid formed the pores in the glassy carbon. The modifications of the silica skeletal structures did not produce reproducible changes of the surface area of the carbon monolith. Better tuning of the silica monolith porosity would ultimately allow for more control of the porosity of the carbon microstructures.

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