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...
Atrial fibrillation (AF) is the most common supraventricular tachyarrhythmia and its prevalence is expected to increase with the aging population. However, the mechanisms AF initiation, maintenance and termination are not completely understood. The surface electrocardiogram (ECG) characteristics are a direct reflection of pathophysiologic events in the atria and can be...
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...
This dissertation demonstrates how self-assembly can direct nanoscale ordering and optimize electronic properties of organic semiconductors, as well as organic-inorganic hybrids. In excitonic solar cells, controlling the ordering and interfaces between electron-transporting (n-type) and hole-transporting (p-type) domains is crucial. In addressing this challenge, hybrid nanostructures were designed by mineralization of...
Granular matter and living cells represent two extremes of what have come to be regarded as complex systems - systems characterized by a richness in global behavior that is not easily deduced from the interactions of their individual parts, even when those interactions are simple and well understood. On the...
The work presented in this dissertation focuses on ceramic anode materials for solid oxide fuel cells (SOFCs). The primary goal was to characterize the anode and relate the electrochemical behavior to the microstructure. The anode that was most extensively studied in this work was a composite of Gd0.10Ce0.90O1.95 (GDC) and...
The self-assembly of quantum dots (QDs) in thin solid films is an important area of nanotechnology with many relevant applications. In the present thesis, three problems related to the growth and self-assembly of QDs are investigated.
In Chapter 1, a new instability mechanism for the formation of QDs associated with...
Living organisms grow precisely controlled assemblies of inorganic crystals using organic substrates. This observation has inspired the strategy of using synthetic organic templates for the growth of tailored inorganic thin films. It has been previously shown that monomolecular organic layers floating on supersaturated aqueous subphases (Langmuir monolayers) select the structure...
Structural dynamics in three polymer blend systems, differing largely with respect to morphology, have been investigated. The first system, composed of two immiscible homopolymers, exhibits a microstructure of micron-sized droplets dispersed in a matrix phase. We have examined small-angle x-ray scattering (SAXS) as a new approach for conducting in situ...
Oxide surface structures play a key role in many technological processes, including catalysis, thin film growth, and layered structures, and a thorough understanding of surface structures and surface structure dynamics is required in order to better engineer materials systems for these processes. This research works towards understanding these fundamental principles...