Surface-relief, submicron period transmission gratings are fabricated in fused silica. A rigorous vector diffraction code, based on the coupled-wave analysis technique, is used to design and analyze the surface relief gratings. When light with wavelength greater than the grating period encounters such element, only zeroth order transmitted and reflected beams propagate, all other diffracted orders are evanescent. These surface-relief gratings act as homogeneous thin film layers of equivalent refractive indices. The equivalent refractive indices depend on grating characteristics, angle of incidence, and incident light polarization. These gratings can be used as equivalent anti-reflection coatings and as polarization elements. Since the grating structures are etched into the substrate material, these optical elements are durable and chemically resistant compared to resist gratings. Subwavelength elements may play a critical role in high power laser systems where damage resistant antireflection and birefringent materials may not exist. By gaining an understanding and being able to control the many variables involved in the grating fabrication process, one-dimensional and two-dimensional submicron period surface-relief resist gratings with rectangular profiles and precisely controlled dimensions are generated. Subsequent pattern transfer etch into underlying substrate layer resulted in one and two-dimensional gratings in fused silica. One-dimensional gratings fabricated in fused silica behaves as polarization elements, giving a maximum measured phase retardation of 50 degrees. To create a polarization insensitive antireflection structure, two-dimensional surface relief gratings are fabricated. These elements exhibited reflectivities near zero percent. The AR structures also showed broadband performance. Application of two-dimensional AR structures on a 16-level diffractive phase plate reduces the surface reflectance of the multilevel phase plate to 0.2%, from 3.3% of that of a bare fused silica surface. Subwavelength grating elements were found to damage when exposed to 45 mJ/cm² and 13 mJ/cm² of laser radiation at 1064 nm and 351 nm wavelength, respectively. The subwavelength gratings have laser damage thresholds comparable to that of bare fused silica. Initial effort on replicating the subwavelength grating structures in polymers yielded promising results, demonstrating the potential for mass production. Replicated elements exhibited no stress birefringence.

The work contained within this document discusses the polymerization and subsequent characterization of Polypyrrole based electrodes for lithium batteries. Polypyrrole and Polypyrrole/polyethyloxy copolymers were compared and contrasted in an attempt to show the superior kinetics of the copolymer electrode. It was found that the diffusion of dopant ions across the electrode and electrolyte interface was increased by on order of magnitude in the copolymer sample. It was also found that the reversibility of the Polypyrrole electrode was greater than that of the copolymer electrode. While the diffusion coefficient of the copolymer electrode was altered to be comparable to that of the transition metal oxide cathodes in production today, the capacity of the copolymer material is still too low to be considered as an alternative cathode material in the lithium battery industry.

The synthesis, structure, and properties of a number of new octasubstituted phthalocyanines, were investigated in this work. Substituent functionality and design has a profound influence on the film forming, and hence, chemical/physical properties of these model molecular electronic materials. Highly ordered thin films, of the benzyl terminated Pc, (2,3,9,10,16,17,23,24-octa(2-benzyloxyethoxy) phthalocyaninato) copper, CuPc(OC₂OBz)₈ and its di-hydrogen analogue were prepared and characterized. These materials form ordered Langmuir films composed of close packed columnar assemblies. Full compression of these materials produces thin films of stable bilayers that show remarkable mechanical stability, and can be transferred with high efficiency to substrates using a horizontal transfer protocol. The physical, spectroscopic, spectroelectrochemical, electrochemical, and electronic properties of these materials were characterized. These properties are strongly dependent on film morphology and structure. The conductivity of these materials relative to the Pc column axis, is highly anisotropic, and with electrochemical doping, the conductivity along the column axis is ca. 10⁻⁶ S/cm. 2,3,9,10,16,17,23,24-Octa(2-benzyloxytriethoxy) phthalocyaninato) copper, and di-hydrogen materials were prepared and characterized. These Pc derivatives did not exhibit the extraordinary properties of their shorter chained analogues. Film preparation efforts with these materials produced poorly ordered isotropic films. Chain length and benzyl termination are combined, in CuPc(OC₂OBz)₈, to produce a unique self assembling material with properties comparable to that reported previously for rigid-rod polymeric Pc materials.

Anode passivation can decrease productivity and quality while increasing costs in modern copper electrorefineries. This investigation utilized electrochemical techniques to characterize the passivation behavior of anode samples from ten different operating companies. It is believed that this collection of anodes is the most diverse set ever to be assembled to study the effect of anode composition on passivation. Chronopotentiometry was the main electrochemical technique, employing a current density of 3820 A m⁻². From statistical analysis of the passivation characteristics, increasing selenium, tellurium, silver, lead and nickel were shown to accelerate passivation. Arsenic was the only anode impurity that inhibited passivation. Oxygen was shown to accelerate passivation when increased from 500 to 1500 ppm, but further increases did not adversely affect passivation. Nine electrolyte variables were also examined. Increasing the copper, sulfuric acid or sulfate concentration of the electrolyte accelerated passivation. Arsenic in the electrolyte had no effect on passivation. Chloride and optimal concentrations of thiourea and glue delayed passivation. Linear sweep voltammetry, cyclic voltammetry, and impedance spectroscopy provided complementary information. Analysis of the electrochemical results led to the development of a unified passivation mechanism. Anode passivation results from the formation of inhibiting films. Careful examination of the potential details, especially those found in the oscillations just prior to passivation, demonstrated the importance of slimes, copper sulfate and copper oxide. Slimes confine dissolution to their pores and inhibit diffusion. This can lead to copper sulfate precipitation, which blocks more of the surface area. Copper oxide forms because of the resulting increase in potential at the interface between the copper sulfate and anode. Ultimate passivation occurs when the anode potential is high enough to stabilize the oxide film in the bulk electrolyte. The effect of anode impurities or electrolyte concentrations can be related to the formation of one of these films. Reactions occurring after passivation have also been examined. Post-passivation reactions are believed to include silver dissolution, transformation of lead sulfate to lead oxide, and oxygen evolution. Following the sharp potential increase caused by the passivation, silver that has accumulated on the anode surface will dissolve into the electrolyte at a potential between 1.0 and 1.3 V. After the silver has dissolved, the potential increases again at which point the oxidation of lead sulfate to lead oxide occurs. The formation of lead oxide provides a surface with a lower oxygen evolution overpotential. The presence of kupferglimmer also results in a stable lower oxygen evolution potential occurring at approximately 2.0 V.

Composites are known for their unique blend of modulus, strength, and toughness. This study focuses on two types of composites; organic-inorganic hybrids and the mineralization of highly swollen polymer gels. Both of these composite systems mimic the biological process of composite formation, known as biomineralization. Biomineralization allows for the control of the precipitating phase through an interaction with the organic matrix. This allows higher volume fractions of inorganic material than can be achieved by many traditional processing techniques. Solid freeform fabrication is a processing method that builds materials by the sequential addition of thin layers. As long as the material can easily be converted from a liquid to a solid, it should be amenable for this processing technique. Freeform fabrication has three distinctions from traditional processing techniques that may enable the formation of composite materials with improved mechanical properties. These are the sequential addition of layers, which allows a layer by layer influence of chemistry, the ability to form complex geometries, and finally, extrusion freeform fabrication has been shown to align fibers due to the extrusion of the slurry through a needle. Cracking and shrinkage still play a major role in forming solid parts. The use of an open mesh structure in combination with proper materials selection allowed the formation of highly loaded composite materials without cracking. The modulus values of these materials ranged from 0.1 GPa to 6.0 GPa. The mechanical properties of these materials were modeled.

The advanced casting modeler requires accurate viscosity and diffusivity data of liquid metals and their alloys. The present work discusses the use of equilibrium and non-equilibrium molecular dynamics techniques to obtain such data without having to rely on oversimplified phenomenological expressions or difficult and expensive experiments. Utilizing the embedded atom method (EAM), the viscosities and diffusivities for a series of equilibrium and non-equilibrium molecular dynamics simulations of nickel, aluminum, and nickel-aluminum alloys are presented. A critical comparison between the equilibrium and non-equilibrium methods is presented. Besides the transport properties, structural data for the liquids are also evaluated. EAM does a poor job of describing the transport properties of nickel-aluminum alloys, particularly near the equiatomic concentration. It has been suggested that charge transfer between nickel and aluminum atoms is responsible for the discrepancy between numerical calculations and available experimental data. A modified electronic distribution function has been developed to simulate the charge transfer associated with compound formation. The effects of such a "charge transfer" modification to the embedded atom method are evaluated. The results of these simulations indicate that the embedded atom method combined with molecular dynamics may be used as a method to predict reasonably the transport properties.

There are three fundamental mechanisms in optical systems that contribute to image degradation: aperture diffraction, geometrical aberrations caused by residual design errors, and scattering effects due to optical fabrication errors. Diffraction effects, as well as optical design errors and fabrication errors that are laterally large in nature (generally referred to as figure errors), are accurately modeled using conventional ray trace analysis codes. However, these ray-trace codes fall short of providing a complete picture of image degradation; they routinely ignore fabrication-induced errors with spatial periods that are too small to be considered figure errors. These errors are typically referred to as mid-spatial-frequency (ripple) and high-spatial-frequency (micro-roughness) surface errors. These overlooked, but relevant, fabrication-induced errors affect image quality in different ways. Mid-spatial-frequency errors produce small-angle scatter that tends to widen the diffraction-limited image core (i.e. for a system with a circular exit pupil, this is the central lobe of the Airy pattern), and in doing so, reduces the optical resolution of a system. High-spatial-frequency errors tend to scatter energy out of the image core into a wide-angle halo, causing a reduction in image contrast. Micro-roughness and ripple are inherent aspects of the less conventional, small-tool-based optical fabrication approaches. It is especially important in these cases to specify these errors accurately during the design phase of a project, and deterministically monitor and control them during the fabrication phase of a project. Surprisingly, most current approaches to this issue employ some guessing and "gut feel" based on past experience, because accurate theories and analysis tools are not readily available. This dissertation takes the first step towards solving this problem by describing a Fourier-based approach for classifying and quantifying surface errors that can be present in a fabricated optical surface. Classical scalar diffraction theories and scatter theories are reviewed and their strengths, weaknesses and misuses are discussed. Then, this dissertation focuses on the development of more accurate surface scatter theories. Modified surface scatter theories are presented that do not exhibit the small angle or smooth surface limitations that are inherent in other theories. These improvements are especially critical for surfaces considered rough with respect to the test wavelength or for systems where large scatter and/or incidence angles are present. Predictions from these modified theories are then compared to and shown to be in excellent agreement with experimental measurements.

The safe disposal of arsenic-containing waste has been a difficult problem for the mining and metallurgical industry. One of the solutions to the arsenic problem is the precipitation of scorodite, an arsenic-containing mineral. Scorodite is reported to be relatively stable over a wide range of pH, and therefore may be a preferred disposal option. The effect of organic complexing agents on scorodite stability, however, is largely unknown. The present study is a phenomenological investigation into the dissolution kinetics of scorodite in the presence of oxalic acid under varying conditions of pH, oxalic acid concentration and temperature. The effect of scorodite particle size was also investigated. The morphological changes accompanying the dissolution process were examined by SEM and TEM analyses. Dissolution curves were divided into a linear induction period and a post-induction period. Activation energies were determined. Complete dissolution data were fit to the Prout-Tompkins/Austin-Rickett model. Dissolution data are indicative of auto-accelerated processes. The rapid increase in dissolution rate following the induction period is believed to be associated with an increase in the effective surface area. Pitting was observed on the surface of scorodite in the early stages of dissolution. In the later stages of dissolution, these pits were observed to grow and coalesce, in many cases resulting in the formation of dissolution holes.

This study investigates various properties of titanium oxide thin films. The samples are prepared by electron-beam evaporation of the Ti₂O₃ material in an oxygen environment. Papers about the vaporization study of the titanium-oxygen system are reviewed; special attention is paid to the congruent vaporization in the titanium-oxygen system. The occurrence of congruent vaporization in our coating system is discussed. The compositions of the films are identified by Rutherford Backscattering Spectrometry. The effect of water vapor and the substrate temperature on the oxygen contents in RBS measurements is discussed. The optical properties of the samples are measured. With the spectrophotometric measurements, the methods for deriving the optical constants of transparent and opaque films are developed. The absorption of the TiO₂ film is investigated, and the corresponding mechanisms are discussed. The envelope method is employed to find the optical band gap of the TiO₂ film. The electrical resistivity of the titanium oxide films are measured with the four-point probe method, and the phenomenon of metal to insulator transition is demonstrated. The tensile stresses in our titanium oxide films are examined with a Nomarski microscope. The grain boundary model is adopted to explain the influence of thickness and oxygen content on the stresses development in thin film. Molecular dynamics simulation is used to study the structure and the thermal expansion of titanium dioxide rutile.

A general dynamic wetting model is presented in which surface and gravitational driving energies are balanced against energy lost through bulk viscous dissipation. Behavior is described in terms only of independently measurable quantities, with no adjustable parameters. Additionally, the model can be expressed so as to predict liquid viscosity as a function of dynamic wetting behavior. Application of the model to a lead-silicate liquid on a gold substrate demonstrate excellent agreement of the model with experiment. The general framework of the model is especially amenable to the incorporation of other physico-chemical processes which may impact dynamic wetting phenomena. Examples are given which extend the model to specific cases where substrate roughness and/or substrate dissolution are important. Additionally, the dynamic wetting model is extended to porous substrates, accounting for the effects of composite interface formation and depletion of the liquid via capillary flow.