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|Title:||Oxygen as a Mass Transport Probe in Polymer Films (Chronocoulometry, Hydrodynamic)|
|Author(s):||Morris, Susan Elaine|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Techniques for exploration of physical properties of a representative electrocatalysis model (ferricyanide coulombically bound into protonated poly(vinylpyridine)) through diffusion of a mass transport probe (molecular oxygen) have been developed. Detection of oxygen diffusion through several ferricyanide-loaded PVP films on a rotating disk electrode allows evaluation of permeation coefficients. (kD(,S)). A background-subtraction chronocoulometric technique allows the examination of diffusion behavior within such films primarily in a chosen oxidation state. For the system investigated, oxygen diffusion occurs either rapidly or within polymer-enclosed solvent pools and does not reflect viscosity changes in the polymer phase with oxidation state.
A new technique has been tested for simultaneous determination of analyte diffusion coefficient and (n-value-concentration) product, without the need for standards. Hydrodynamic chronocoulometry is easily applied as a single type of measurement in a few steps. Analysis provided results within 10-15% of literature and prepared values for dissolved oxygen and a benzoquinone standard in aqueous solution.
A film-layering method has been used to encapsulate a normally water-soluble polymer with an immobilized fluorophore into a PVP film for use in aqueous solution. Unexpected sensitivity of the polymer immobilized fluorophore to the oxidation state of ferricyanide in the film prevented the use of oxygen quenching of fluorescein isothiocyate for diffusion coefficient determination. Enhancement of polymer-bound FITC luminescence by ferricyanide is documented.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-15|