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dc.contributor.author Priyantha, Namal en_US
dc.date.accessioned 2009-07-15T17:25:06Z en_US
dc.date.available 2009-07-15T17:25:06Z en_US
dc.date.issued 1990 en_US
dc.identifier.uri http://hdl.handle.net/10125/9495 en_US
dc.description Typescript. en_US
dc.description Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. en_US
dc.description Includes bibliographical references (leaves 154-163) en_US
dc.description Microfiche. en_US
dc.description xvi, 163 leaves, bound ill. 29 cm en_US
dc.description.abstract Platinum electrodes coated with a mixture of poly(4vinylpyridine- co-styrene) [PVPCS] and hexadecyl methanesulfonate [HDMS] show novel voltammetric features in aqueous solution. Platinum oxide and platinum-pyridyl complexes formed at anodic potentials are reduced at different potentials. The platinum-pyridyl complex is also formed in aqueous pyridine solutions. The formation of this complex competes with the adsorption of small polar organic molecules from solution. The diffusion of metal ions such as cu^2+/cu^+, Fe^3+/Fe^2+, and Co^2+/Co^0 through PVPCS+HDMS polymer coatings is complicated and cannot be explained by simple diffusion phenomena. The rate of diffusion at the polymer coated electrode is much slower than that at a bare electrode. The estimated apparent diffusion coefficients show a reciprocal relationship with the bulk concentration which is due to the formation of metal-pyridyl complexes. Metal ions in anionic form such as Fe(CN)6^3-/Fe(CN)6^4- do not form complexes and show only restricted diffusion. Adsorption of acetate onto platinum surfaces to form a platinum-acetate complex is apparent voltammetrically. The equilibrium between platinum-acetate and platinum-hydroxide complexes formed at anodic potentials has an equilibrium constant of 1.3X10^10. The apparent number of acetate ions adsorbed per adsorption site is 1.6. Adsorption of acetate is mimicked in studies of zinc acetate-coatings on platinum in aqueous solution. Metal acetate coatings on platinum electrodes are unusually stable due to the adsorption of acetate. Moreover, platinum electrodes with thick zinc acetate coatings behave as zinc electrodes which show the reduction of Zn2+ in aqueous solution. The voltammetry of zinc acetate and zinc acetate+HDMS coatings show a dramatic change in the presence of methanol. The sensitivity of organic molecules to PVPCS and metal acetate electrode coatings points toward the development of a new class of analytical sensors. en_US
dc.language.iso en-US en_US
dc.relation Theses for the degree of Doctor of Philosophy (University of Hawaii at Manoa). Chemistry; no. 2481 en_US
dc.rights All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner. en_US
dc.subject Surface chemistry en_US
dc.subject Voltammetry en_US
dc.subject Metals -- Absorption and adsorption en_US
dc.subject Diffusion processes en_US
dc.title Interfacial behavior and charge transfer reactions at chemically modified electrodes en_US
dc.type Thesis en_US
dc.type.dcmi Text en_US

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