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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
Subject(s):Chemistry, Analytical
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.
Issue Date:1986
Description:154 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
Other Identifier(s):(UMI)AAI8701571
Date Available in IDEALS:2014-12-15
Date Deposited:1986

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