Exploring unconventional hydrocarbon reservoirs and enhancing the recovery of hydrocarbon from conventional reservoirs are necessary for meeting the society's ever-increasing energy demand and requires a thorough understanding of the multiphase interfacial and transport phenomena in these reservoirs. This dissertation performs pore-scale studies of interfacial thermodynamics and multiphase hydrodynamics in shale reservoirs and conventional oil-brine-rock (OBR) systems. In shale gas reservoirs, the imbibition of water through surface hydration into gas-filled mica pores was found to follow the diffusive scaling law, but with an effective diffusivity much larger than the self-diffusivity of water molecules. The invasion of gas into water-filled pores with width down to 2nm occurs at a critical invasion pressure similar to that predicted by the classical capillary theories if effects of disjoining pressure and diffusiveness of water-gas interfaces are considered. The invasion of oil droplets into water-filled pores can face a free energy barrier if the pressure difference along pore is small. The computed free energy profiles are quantitatively captured by continuum theories if capillary and disjoining pressure effects are considered. Small droplets can invade a pore through thermal activation even if an energy barrier exists for its invasion. In conventional oil reservoirs, low-salinity waterflooding is an enhanced oil recovery method that relies on the modification of thin brine films in OBR systems by salinity change. A systematic study of the structure, disjoining pressure, and dynamic properties of these thin brine films was performed. As brine films are squeezed down to sub-nanometer scale, the structure of water-rock and water-oil interfaces changes marginally, but that of the electrical double layers in the films changes greatly. The disjoining pressure in the film and its response to salinity change follow the trend predicted by the DLVO theory, although the hydration and double layer forces are not simple additive as commonly assumed. A notable slip between the brine film and the oil phase can occur. The role of thin liquid films in multiphase transport in hydrocarbon reservoirs revealed here helps lay foundation for manipulating and leveraging these films to enhance hydrocarbon production and to minimize environmental damage during such extraction. / Doctor of Philosophy / Meeting the ever-increasing energy demand requires efficient extraction of hydrocarbons from unconventional reservoirs and enhanced recovery from conventional reservoirs, which necessitate a thorough understanding of the interfacial and transport phenomena involved in the extraction process. Abundant water is found in both conventional oil reservoirs and emerging hydrocarbon reservoirs such as shales. The interfacial behavior and transport of water and hydrocarbon in these systems can largely affect the oil and gas recovery process, but are not well understood, especially at pore scale. To fill in the knowledge gap on these important problems, this dissertation focuses on the pore-scale multiphase interfacial and transport phenomena in hydrocarbon reservoirs. In shales, water is found to imbibe into strongly hydrophilic nanopores even though the pore is filled with highly pressurized methane. Methane gas can invade into water-filled nanopores if its pressure exceeds a threshold value, and the thin residual water films on the pore walls significantly affect the threshold pressure. Oil droplet can invade pores narrower than their diameter, and the energy cost for their invasion can only be computed accurately if the surface forces in the thin film formed between the droplet and pore surface are considered. In conventional reservoirs, thin brine films between oil droplet and rock greatly affect the wettability of oil droplets on the rock surface and thus the effectiveness of low-salinity waterflooding. In brine films with sub-nanometer thickness, the ion distribution differs from that near isolated rock surfaces but the structure of water-brine/rock interfaces is similar to their unconfined counterparts. The disjoining pressure in thin brine films and its response to the salinity change follow the trend predicted by classical theories, but new features are also found. A notable slip between the brine film and the oil phase can occur, which can facilitate the recovery of oil from reservoirs.

In the first part of this two part thesis, interaction parameters of nitrocellulose with various solvent systems were investigated by Inverse Gas Chromatography. From these data, the solubility parameters of nitrocellulose were determined at a series of nitration levels which were used to guide the selection of suitable plasticizers for nitrocellulose films. Subsequent dynamic mechanical experiments were then used to evaluate the effectiveness of the blend formulations in broadening the glass transition dispersion of the nitrocellulose blended films; in addition, stress-strain experiments were done in order to evaluate the tensile modulus of the nitrocellulose blends. In the second part of this thesis, both dynamic mechanical thermal analysis and dielectric thermal analysis were used to evaluate the relaxation properties of thin film polysulfone coatings and the effect of substrate surface topography on these properties. Both dynamic mechanical and dielectric thermal analysis revealed that the topographical nature of the substrate influenced the linear viscoelastic properties of the thin film coatings and that the extent of this influence was dependent on the coating thickness. / Master of Science

Seebeck and resistivity measurements are made on thin film CdS and Zn_xCd_1-xS samples in an apparatus of original design over a temperature range from near liquid nitrogen temperature to room temperature. The temperature dependence of mobility and carrier concentration is studied in CdS films of varying thicknesses (3 µm to 14.0 µm) and in Zn_xCd_1-xS films of varying zinc content (0 ≤ x ≤ .35) . Scattering is found to be grain boundary dependent in all films except the thinest CdS film measured (3.0 µm) in which lattice scattering dominates. The grain boundary barrier height increases with film thickness in CdS films due to a decrease in carrier concentration as film thickness increases making electron traps at the grain boundary influential. As the zinc concentration is increased the carrier concentration decreases and the grain boundary barrier height increases as seen in the CdS films. / Master of Science

The resistivity-size effect has emerged as an obstacle in our pursuit of ever shrinking electronic devices. Interconnects and vias are the nanoscale copper conductors connecting within and between layers of a CPU, respectively. New materials and methods are required to address this problem. In particular, there is a critical need for a theoretical framework which can evaluate the properties of new materials in a way that reflects real-world performance. To this end, a computational methodology is developed by introducing an ab initio parameterized tight-binding model to accurately calculate electronic structure and simulating electronic transport via the calculation of the Kubo-Greenwood conductivity tensor. Transport properties are computed using the kernel polynomial method, a highly scalable approach wherein physical quantities can be represented as a weighted sum of Chebyshev polynomials. Using this combined approach, it is possible to simulate mesoscale electronic transport for systems with over 10^6 sites containing various forms of realistic disorder. Through the use of ensemble calculations, an examination of resistivity due to surface disorder and disorder due to realistic phonon fields is presented.

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A novel in-situ stress measurement technique to study the formation kinetics of multi component oxide thin films was developed and was applied to PbTiO₃. Single phase PbTi 0₃ thin films were formed from the reaction between films in the deposited PbO ITi0₂ multilayer. The film stoichiometry was accurately controlled by depositing individual layers of the required thickness. Development of film stresses associated with the formation of the product layer at the PbO/Ti0₂ interface of the multilayers was used to monitor growth rate of the PbTiO₃ layer. It was found that growth of the PbTiO₃ phase obeyed the parabolic law and the effective activation energy was estimated to be 108 kJ/mole. It is believed that the mechanism of this reaction was dominated by grain boundary diffusion of the participating cations. / Ph. D.

High precision electronics are particularly susceptible to swings in resistance that occur in most materials when temperatures change. To make electronics with consistent performance across a wide range of temperatures, near-zero temperature coefficient of resistivity (nz-TCR) materials are needed. Further, as technology shrinks and we approach the angstrom era, methods of depositing nz-TCR materials of sufficient thinness are also necessary. This study demonstrates the design and deposition of such thin films using atomic layer deposition (ALD). Precise composition control is possible due to the self-limiting and highly conformal nature of ALD. Films made include, firstly, a conducting form of titania (TiOx) – typically an insulator, known as black titania, with a conductivity 108 times higher than TiO2. Next, metallic, nanocrystalline ruthenium film was deposited via plasma-enhanced ALD. Then, composites of black titania - ruthenium were made to explore how composition and structure impact TCR. Lastly, films of silicon-doped titanium nitride were also deposited with varying at% silicon. This set of films produced an extreme near-zero temperature coefficient over a wide temperature range. The films were characterized with many methods, including scanning and tunneling electron microscopy, x-ray photoelectron spectroscopy, x-ray diffractometry, spectroscopic ellipsometry, van der Pauw resistivity measurements, and Hall measurements to obtain carrier concentration and carrier mobility. This comprehensive investigation thus reveals the relationship between structure, composition, and TCR, facilitating the future design of nz-TCR materials.