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The structure and physical properties of layered oxides and carbon materials were studied. Two layered carbon materials were studied: carbon nanotubes (CNTs) synthesized by electron irradiation from amorphous carbon in situ in a transmission electron microscope (TEM) and a carbon and silver nanocomposite consisting of graphitic carbon nanospheres encapsulating Ag nanoparticles. In the CNT experiments, the effect of electron irradiation in the TEM is shown to alter drastically their structure and properties, even being able to transform amorphous carbon into a CNT. This suggests a possible alternative synthesis technique for the production of CNTs, in addition to providing a method for tailoring their properties. The structure and magnetic properties of the carbon and silver nanocomposite was characterized with x-ray diffraction, scanning and transmission electron microscopy techniques, and magnetic susceptibility measurements with a superconducting quantum interference device (SQUID) magnetometer. While the sp² bonding gives a grapheme sheet its mechanical properties, the p[subscript pi] electrons are responsible for its electronic and magnetic properties. In a flat graphene sheet the p[subscript pi] electrons are itinerant, but in a narrow p[subscript pi] band. The introduction of curvature to the graphene sheets that encapsulate the Ag nanoparticles is demonstrated to narrow the p[subscript pi] band sufficiently to result in "ferromagnetic" behavior. A model that is able to explain spin localization and ferrimagnetic spin-spin interactions in graphitic materials with positive curvature is presented. Layered oxides from the family of the P2 Na[subscript x]CoO₂ structure were synthesized and their properties studied. Na[subscript x]CoO₂ has a rich phase diagram ranging form a promising Na-rich thermoelectric composition to the hydrated Na-poor composition Na[subscript 0.33]CoO₂· 1.3H₂O that is superconductive. Intermediate to these two Na compositions exists an insulating phase with x [approximately equal to] 0.5 that presents a variety of interesting structural, magnetic, thermoelectric, and electronic behavior. Investigations of Na[subscript x]CoO₂ that probe the role of H₂O in the superconductive Na[subscript 0.33]CoO₂· 1.3H₂O are presented and conclude that H₂O plays a more active role than a passive lattice spacer. The relationship between Na ordering and an interesting magnetic behavior observed with [chi](T) measurements of annealed NaxCoO₂ and Sr[subscript x/2]CoO₂ samples is determined and found to correspond to a (2a x 2a) superstructure. The properties of NaxCoO₂ (x [approximately equal to] 0.5) are reviewed and thermoelectric S(T) measurements are made in order to develop a model that is able to explain the salient features of the NaxCoO₂ (x [approximately equal to] 0.5) phase. / text

Label-free detection techniques have an important role in many applications, such as situations where few molecules -- rather than low molarity -- need to be detected, such as in single-cell screening. While surface plasmon resonance (SPR) scattering from metal nanoparticles has been shown to achieve significantly higher sensitivity in gene arrays, such an approach has not been demonstrated for protein arrays. SPR-based sensors could either use simple absorption measurement in a UV-Vis spectrometer or possibly surfaceenhanced Raman spectroscopy as the detection mechanism for molecules of interest. However, non-spherical particles are needed to achieve high sensitivity and field enhancement that is a requirement in both techniques, but these shapes are not easy toproduce reproducibly and preserve for extended periods of time. Here I present a carbonbased template-stripping method combined with nanosphere lithography (NSL). This fabrication allows to preserve the sharp features in atomically flat surfaces which are a composite of a non-spherical metal nano-particle (gold or silver) and a transparent embedding material such as glass. The stripping process is residue-free due to the introduction of a sacrificial carbon layer. The nanometer scale flat surface of our template stripping process is also precious for general protein absorption studies, because an inherent material contrast can resolve binding of layers on the 2 nm scale. These nanocomposite surfaces also allow us to tailor well-defined SPR extinction peaks with locations in the visible or infrared spectrum depending on the metal and the particle size and the degree of non-symmetry. As the particle thickness is reduced and the particle bisector length is increased, the peak position of the resonance shifts to the red. Not only the peak position shifts, but also the sensitivity to environmental changes increases. Therefore, the peak position of the resonance spectrum is dependent on the dielectric environmental changes of each particle, and the particle geometries. The resulting silver or gold nanoparticles in the surface of a glass slide are capable of detecting thiol surface modification, and biotin-streptavidin protein binding events. Since each gold or silver particle principally acts as an independent sensor, on the order of a few thousand molecules can be detected, and the sensor can be miniaturized without loss of sensitivity. UNSL-Au metal nanoparticle (MNP) sensors achieve the sensitivity of close to 300 nm/RIU which is higher than any other report of localized surface plasmon resonance (LSPR) sensors except gold nanocrescents. Finite-difference-time-domain (FDTD) and finite-element-method (FEM) numerical calculations display the influence of the sharp features on the resonance peak position. The maximum near-field intensity is dependent on the polarization direction, the sharpness of the feature, and the near-field confinement from the substrate. 3D FDTD simulation shows the local refractive index sensitivity of the gold truncated tetrahedron, which is in agreement with our experimental result. Both experimental and numerical calculations show that each particle can act as its own sensor.

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Foams have been used successfully in the industry for both drilling and fracturing. These foams usually consist of both an aqueous liquid phase and a gas phase; air, nitrogen, and/or CO2 are the most common. Due to the aqueous liquid component in the foam, drilling and fracturing in shale formations can cause swelling and collapsing of the rock through formation invasion. Sensoy et al.(2009) has shown that the addition of nanoparticle dispersions to water based fluids reduces the amount of water invading the shale and has been used as a kickoff point for this research. Results presented in this thesis show that the addition of nanoparticles to foams enhances the performance of these fluids by reducing their invasion into shale. The use of foams allows for a low concentration of nanoparticles making this technology much more economically feasible for field testing and use. / text

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