xvi, 120 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / The interface between water and an organic liquid is present in a variety of biological, environmental, and chemical processes throughout science and nature. Issues such as environmental remediation and ion transport are governed by the properties of these interfaces, thus the importance of understanding them at the molecular level is apparent. The research in this dissertation shows how the structure and bonding of the liquid-liquid interface changes as the interfacial environment is altered. Vibrational sum-frequency spectroscopy (VSFS), a surface specific, non-linear optical technique, is employed for these interfacial studies. The interfacial OH stretching modes are examined using VSFS under different conditions including organic liquids of varying polarity, as well as addition of acid, base, and salts to the aqueous phase. The effects of these different conditions on the water molecules' interactions both with each other and with the non-aqueous liquid are studied in order to better characterize and understand this important system.
The effect of polarity of the non-aqueous phase is presented first through investigations of different mixed halocarbon liquid-water interfaces and the neat chloroform-water interface. These studies show that as the overall polarity of the organic phase increases, the water molecules exhibit less overall orientation and undergo some weak bonding interactions with the non-aqueous liquid.
Next, the influence of different salts on the water structure at the interface is studied. Examining this system shows that the dissolved ions, specifically the anions, are present within the interface and significantly alter the orientation and bonding of the interfacial water molecules. The charge, size, and polarizability of the anions all play a role in determining how the water orientation is changed within the interface.
Finally, the water-like ions H 3 O + and OH - are examined at the liquid-liquid interface by changing the pH of the aqueous phase through addition of HCl or NaOH. At the extremes of the pH scale, the acid and base have ordering or disordering effects, respectively, on the water structure within the interfacial region. / Adviser: Geraldine Richmond
| Identifer | oai:union.ndltd.org:uoregon.edu/oai:scholarsbank.uoregon.edu:1794/10069 |
| Date | 03 1900 |
| Creators | McFearin, Cathryn LeAn, 1979- |
| Publisher | University of Oregon |
| Source Sets | University of Oregon |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | University of Oregon theses, Dept. of Chemistry, Ph. D., 2009; |
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