Investigation of the structure and properties of thin liquid films at bare and organically-modified metal substrates using a novel emersion approach

The interfacial structure and properties of thin liquid films at bare and organically-modified metal substrates are investigated using a novel emersion approach. Since essentially no bulk solution remains after emersion, this approach provides a method by which a variety of surface spectroscopic techniques can be applied to investigate the solid-liquid interface with interfacial selectivity.; The effect of emersion velocity on the emersed layer thickness of water, methanol, acetonitrile, chloroform, 1-butanol and 1-pentanol at 11-mercapto-1-undecanol-modified Ag substrates is studied using manual-null ellipsometry. It was found that the emersed layer thicknesses were sensitive to changes in emersion velocity. A simple Newtonian fluid model was used to describe the emersion process in terms of the interplay between hydrodynamic and intermolecular forces. From this model, it is proposed that a shear plane develops at some distance away from the solid surface when the hydrodynamic forces are great enough to overcome the intermolecular forces between the liquid layers.; Ag surfaces modified with undecanethiol, 11-mercapto-1-undecanol and 11-mercaptoundecanoic acid self-assembled monolayers (SAMs) are emersed from water, methanol, acetonitrile and chloroform, and the thicknesses of the resulting emersed interfaces measured by manual-null ellipsometry. As the terminal group of the SAM-modified Ag surface becomes more polar (−CH₃ < −OH < −COOH), the emersed water, methanol, acetonitrile and chloroform thickness changes. These results suggest that the thickness of the emersed solvent layer is sensitive to the chemical nature of the solid interface.; Surface Raman spectroscopy was used to elucidate the interfacial structure before and after the emersion of organically-modified Ag surfaces from water, acetonitrile and methanol. The results from this study indicate that the structure of the emersed layer is different from that of the bulk liquid and that the chemical nature of the interface can influence the resulting structure.; Finally, a novel emersion infrared reflectance absorbance spectroscopy technique was developed and used to investigate the interfacial structure resulting from the emersion of bare Ag and Pt substrates from a variety of aqueous solutions.*; *This dissertation is multimedia (contains text and other applications not available in printed format). The CD requires the following system applications: QuickTime; Windows MediaPlayer or RealPlayer.