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dc.contributor.advisorBerg, John Cen_US
dc.contributor.authorGacek, Matthewen_US
dc.date.accessioned2015-05-11T20:03:48Z
dc.date.available2015-05-11T20:03:48Z
dc.date.submitted2015en_US
dc.identifier.otherGacek_washington_0250E_14205.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1773/33114
dc.descriptionThesis (Ph.D.)--University of Washington, 2015en_US
dc.description.abstractThe creation and stabilization of electric charge in apolar environments (dielectric constant ≈ 2) has been an area of interest dating back to when an explanation was sought for the occurrence of what are now known as electrokinetic explosions during the pumping of fuels. More recently attention has focused on the charging of suspended particles in such media, underlying such applications as electrophoretic displays (e.g., the Amazon Kindle® reader) and new printing devices (e.g., the HP Indigo® Digital Press). The endeavor has been challenging owing to the complexity of the systems involved and the large number of factors that appear to be important. A number of different, and sometimes conflicting, theories for particle surface charging have been advanced, but most observations obtained in the authors' laboratory, as well as others, appear to be explainable in terms of an acid-base mechanism. Adducts formed between chemical functional groups on the particle surface and monomers of reverse micelle-forming surfactants dissociate, leaving charged groups on the surface, while the counter-charges formed are sequestered in the reverse micelles. For a series of mineral oxides in a given medium with a given surfactant, surface charging (as quantified by the maximum electrophoretic mobility or zeta potential obtained as surfactant concentration is varied) was found to scale linearly with the aqueous PZC (or IEP) values of the oxides. Different surfactants, with the same oxide series, yielded similar behavior, but with different PZC crossover points between negative and positive particle charging, and different slopes of charge vs. PZC. Thus the oxide series could be used as a yardstick to characterize the acid-base properties of the surfactants. This has led directly to the study of other materials, including surface-modified oxides, carbon blacks, pigments (charge transfer complexes), and polymer latices. This dissertation focuses on the acid-base mechanism of particle charging in the context of the many other factors that are important to the phenomenon, including the presence of water, of other components (e.g., synergists, contaminants, etc.), and of electric field effects. The goal is the construction of a road map describing the anticipated particle charging behavior in a wide variety of systems, assisting in the choice or development of materials for specific applications.en_US
dc.format.mimetypeapplication/pdfen_US
dc.language.isoen_USen_US
dc.rightsCopyright is held by the individual authors.en_US
dc.subjectacid-base interaction; apolar media; interfacial phenomena; particle charge; trace wateren_US
dc.subject.otherChemical engineeringen_US
dc.subject.otherchemical engineeringen_US
dc.titleSurfactant mediated acid-base particle charging in apolar mediaen_US
dc.typeThesisen_US
dc.embargo.termsOpen Accessen_US


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