In support of a scientific foundation for the predictive design of composition and processing of quench and partition (Q&P) martensite/austenite TRIP steels, theory of coupled diffusional/displacive transformation is experimentally calibrated to control austenite carbon content and its associated mechanical stability. Under paraequilibrium constraint, the calibration quantifies an effective BCC stored...
In polymer nanocomposites (PNCs), the physical and chemical interactions at the polymer matrix-filler interface lead to local variations in polymer properties, creating a substantial interphaseregion in the vicinity of the interface. Quantifying the significance of the interphase effect in the presence of substrates or nanoparticles is of essential importance in...
Intermolecular charge transfer between electron-rich donor and electron-poor acceptor molecules offer great promise in the development of novel, low-cost electronic materials. It is hypothesized that control over the intermolecular interactions and supramolecular self-assembly of these systems could tune electronic properties and discover new functions. To that end, a series of...
The use of polymeric membranes have become ubiquitous in our daily lives. From simple chip bags to million-dollar cockpits, these membranes find diverse applications in packaging, protective coating, electronic device, gas and liquid separation, and medicine. The 2-dimentional geometry of the membranes offered unique mechanical and interfacial properties that often...
Perovskite oxide materials for the wide array of properties that make them candidate materials for application ranging from catalysis, to electronics, to beyond-Moore computation. As many of these oxides share similar structures they can be combined in a seemingly-endless number of ways to produce the desired properties for a given...
The assembly of nanoscale building blocks into larger ensembles with well-defined architecture has the potential to create entirely new classes of designer photonic and plasmonic metamaterials with unique properties not found in nature. Electromagnetic metasurfaces, or 2D metamaterials, operating at optical wavelengths are of particular interest due to ease of...
This dissertation presents research on solid oxide fuel cell (SOFC) cathodes. It specifically covers two main topics: the electrochemical performance of porous two-phase composite cathodes, and the degradation mechanisms of porous single-phase mixed conducting cathodes. Current-voltage measurement and electrochemical impedance spectroscopy were used extensively to evaluate the cell performance. The...
Self-assembly is an important process in biological system to build various bioactive structures from small amphiphilic molecules. The structural versatility of amphiphile self- assembly also provides a unique platform for the design of functional soft materials with controllable structural features. However, little is known about the correlation between external stimuli,...
Patterning hierarchical structures in three-dimension (3D) has created nature-inspired functional surfaces. Gecko feet structures have been mimicked for reversible adhesive properties, shark skin for reduced drag, and lotus leaves for self-cleaning surfaces. Rational design of out-of-plane patterns across multiple length scales is crucial because each micro- and nano-feature has different...
Sparked by the isolation of graphene in 2004, the research community has developed a family of 2D materials with distinct functionalities, enabling rapid demonstrations of entirely 2D devices with applications in energy, electronics, sensors and medicine. The desire to capitalize on the fantastic properties of 2D materials motivates ongoing efforts...
Complex oxides show great potential for future devices as they offer functionalities beyond what can be delivered by conventional semiconductors. Among the complex oxides, the ABO$_{3}$ perovskite oxides are the most studied and engineered in the form of thin films and heterostructures. This thesis applies powerful synchrotron-based X-ray characterization tools,...
Plasmonic nanostructures are capable of trapping and confining light at the nanoscale, leading to interesting optical phenomena involving enhanced light-matter interactions. These responses arise in two forms: surface plasmon polaritons propagating on the surface of metal films and localized surface plasmons confined to the surface of metal nanoparticles. Plasmonic modes...
Two-dimensional materials’ “all-surface” architecture presents a new paradigm for investigations into electron confinement effects and surface phenomena. However, synthesizing, characterizing, and ultimately engineering the properties of 2D materials represents a formidable challenge. This thesis presents several cases of isolating novel 2D materials via vapor-based syntheses. Vapor-based syntheses allow for reproducible...
Lithium ion batteries (LIBs) have been the most prominent electrochemical energy storage technology over the past decades and enabled the wireless evolution of portable electronic devices. Yet the expanded use of renewable but intermittent energy sources coupled with increasing demand for electric transportation vehicles put forward requirements to electrochemical energy...
Porous metal structures exhibit numerous advantages over dense materials due to their high specific stiffness, strength, damping, energy absorption, and surface areas, making them suitable for applications ranging from actuators to medical implants. However, traditional foam manufacturing methods do not provide sufficient control of the foam micro-architectures, and the creation...
Gels are three-dimensional polymer networks capable of absorbing a large amount of solvent molecules subject to various external stimuli (pH, temperature, light, etc.). They exhibit a rich mechanical behavior and prominent nonlinearity owing to their high flexibility, stimuli-responsiveness and superabsorbency. More compelling are the intriguing morphologies and novel functionalities achieved...
Electromagnetic metamaterials composed of colloidally synthesized plasmonic metal nanoparticles offer new opportunities to probe light-matter interactions. The properties of these structures largely depend on the spatial arrangement of nanoparticles within them. Therefore, new assembly strategies that afford a high level of structural control are expected to enable a broad range...
While synthesis and transformation processes to produce monodisperse nanoparticles are empirically well-developed, the pathways for these reactions as well as the exact role of synthetic agents and binding characteristics of surface moieties remain poorly understood. This lack of understanding is primarily due to the paucity of information about nanoparticle structural...
Technology has advanced rapidly, especially in the twenty-first century, influencing our day-to-day life on unprecedented levels. Most such advances in technology are closely linked to, and often driven by, the discovery and design of new materials. It follows that the discovery of new materials can not only improve existing technologies...
Microkinetic modeling is a powerful tool for creating dynamic and quantitative descriptions of complex systems. These detailed mechanistic models compliment experimental techniques and provide an ability to achieve deeper insights into chemical processes where numerous intermediates are highly reactive and difficult to quantify in the laboratory. This thesis discusses the...