The morphological evolution due to coarsening is analyzed for two distinctive types of microstructure. First, the feasibility of characterizing spatial correlations of interfacial curvature in topologically complex structures is demonstrated with the analysis of bicontinuous two-phase mixtures produced using phase field modeling. For structures produced with both conserved and nonconserved...
This thesis demonstrates the use of dual-beam focused ion beam - scanning electron microscopy (FIB-SEM) for making complete three-dimensional reconstructions of SOFC electrodes in order to better understand the links between processing and performance with respect to microstructure. Sufficient compositional contrast, with nano-scale resolution, between Ni and LSM with respect...
This dissertation examines growth of platinum nanoparticles from vapor deposition on SrTiO3 using a characterization approach that combines imaging techniques and X-ray methods. The primary suite of characterization probes includes atomic force microscopy (AFM), grazing-incidence small-angle X-ray scattering (GISAXS), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and X-ray absorption spectroscopy...
ZnO is a member of the unique class of materials known as transparent conducting oxides (TCOs). TCOs are currently used for many applications including flat panel displays, solar cells, and energy efficient windows. Of particular interest is the possibility of developing materials that have high electron mobilities, such that conductivities...
Wood-derived ceramics and composites have been of interest in recent years due to their unique microstructures, which lead to tailorable properties. The porosity and pore size distribution of each wood type is different, which yields variations in properties in the resultant materials. The thermal properties of silicon carbide ceramics and...
Subsolidus phase relationships within the ZnO-In<sub>2</sub>O<sub>3</sub>-SnO<sub>2</sub> system at 1275 <sup>o</sup>C were established by conventional solid state reaction methods. No new compounds or structures were observed within the ternary diagram. Equilibrium in the ZnO-corner, between the homologous compounds and the spinel phase, was found difficult to achieve. This problem was overcome...
Characterizing the interaction of light and matter has become increasingly important in recent decades, as devices scale down, data transfer speeds up, and the use of photon-based technology (photonics and optoelectronics) becomes widespread. Copper chloride (CuCl) thin films and zinc oxide (ZnO) inverse opal photonic crystals are the two material...
Recent assessment of material property requirements for blast resistant applications, especially for the naval ship hulls, has defined the need to design steels with high stretch ductility and fragment penetration resistance, along with high strength and adequate toughness. Using a system based computational materials design approach, two series of austenitic...
A multicomponent bimodal poly(vinyl acetate) (PVAc) polymer composite has been scientifically designed to increase biaxial plastic flow stabilization for the achievement of large biaxial deformations. For this, a systems-based approach was used for the computational materials design of a high performance bubblegum whose mean in-vivo bubble diameter exceeds that of...
In this work, electron beam induced current (EBIC) and scanning photocurrent microscopy (SPCM) were used to quantitatively investigate the electronic properties of silicon nanowire devices. For the first time, it was shown that minority carrier diffusion lengths in phosphorous-doped silicon nanowires are significantly reduced from their bulk values because of...
Increasing interest in long-life bone implants with reduced mechanical properties reducing the stress-shielding effect and a structure mimicking bone porous architecture has encouraged study and development of fabrication methods for porous NiTi. The main objective of this work was to advance these goals by developing new processing procedures for porous...
Motivated by performance requirements of future medical stent applications, experimental research addresses the design of novel TiNi-based, superelastic shape-memory alloys employing nanoscale precipitation strengthening to minimize accommodation slip for cyclic stability and to increase output stress capability for smaller devices. Using a thermodynamic database describing the B2 and L21 phases...
In recent years, research has expanded the uses of triblock copolymer gels to a wide variety of applications including everything from ceramics processing to regenerative medicine and drug delivery. The research presented in this dissertation focuses on a physically crosslinked, block copolymers gel system in a selective solvent. This system...
Liquid metal melt-lubrication of high-power and high-speed sliding electrical contacts improves electrical current collection and reduces friction. However, armature material loss may cause transition to arcing or plasma contact. Boundary lubrication of the sliding contact with low melting-point alloys can provide comparable improvement in current collection at reduced temperatures. Bismuth,...
The measurement of weak adhesive energies has previously been difficult to obtain. To measure these energies, I designed a technique that uses the combined sensitivities of both a quartz crystal resonator and the inflation of an elastomeric polymer membrane. The surfaces of the quartz crystal and/or the membrane are modified...
The use of composites is increasing as they afford scientists and engineers the ability to combine the advantageous properties of each constituent phase, e.g. metal ductility and ceramic stiffness. With respect to materials design, biomimetics is garnering increasing attention due to the complex, yet efficient, natural microstructures. One such biomimetic,...
The current trend of ceramic nanotechnology has motivated an ever-increasing need to achieve exquisite control over size, shape, and spatial confinement for functional oxide architectures, in an equivalent manner demonstrated for semiconductors. However, the unique nature of ceramics has posed major challenges for most traditional nanofabrication technologies, putting the development...
Metal nanoparticles in polymeric matrices are of particular scientific interest due to their useful ability to self-assemble into complex nanocomposites. Recent examples involve using ultrathin diblock copolymers coupled with metal nanoparticles in the fabrication of novel electronic, magnetic and photonic devices. As this ordering process takes place far from equilibrium...
Two main topics are addressed in this dissertation: (1) adhesion in hydrogels; (2) interfacial interactions between model glassy polymers. A self-assembly technique for the formation of hydrogels from acrylic triblock copolymer solutions was developed, based on vapor phase solvent exchange. Structure formation in the gels was characterized by small angle...
A novel cryogenic variable temperature UHV STM has been constructed and utilized to investigate the dynamical behavior of isolated organic molecules covalently bound to silicon surfaces.
The microscope can be operated from 8-300 K, and exhibits extremely low drift rates. A new design has been implemented for the rails (used...