Dilute Al-Sc-Zr-Si-based aluminum alloys retain their strength for long periods of time at elevated temperatures due to a dispersion of nanometric, coherent, and coarsening-resistant Al3(Sc,Zr) (L12 structure) nanoprecipitates that are formed upon aging. These alloys are attractive for replacement of dense steels and costly Ti alloys in the 250–400 °C...
Water vapor condenses into liquid water when it encounters a cold surface. If the surface temperature is sufficiently low, freezing follows the condensation step, and the process is holistically referred to as condensation frosting. Both phase change processes are fundamental to many industries ranging from water harvesting, thermal management, solar...
Two-dimensional (2D) materials and heterostructures have attracted significant attention for a variety of nanoelectronic and optoelectronic applications. At the atomically thin limit, the material characteristics and functionalities are dominated by surface chemistry and interface coupling. Therefore, methods for comprehensively characterizing and precisely controlling surfaces and interfaces are required to realize...
Deformation in materials with a hierarchical microstructure is expected to be complex because of the interaction between the units that form such a microstructure. The complexity of deformation would be even higher when additional inelastic deformation modes are active in such materials, apart from traditional elastic and plastic deformation modes....
Semiconductor nanowires, such as group IV and III-V nanowires, shows distinct electrical, optical and mechanical properties from their bulk counterparts due to their nanoscale size and 1-D morphology. For example, the quantum confinement effect modulates the band gap of a semiconductor nanowire when its diameter approaches or below the exciton...
Connecting structure and function in nanoscale engineered materials and devices relies on the analysis of the fundamental arrangement of matter, frequently under dynamic conditions. The demand to image structures at fundamental length scales has touched inorganic materials, biology, and frequently hybrid hard/soft materials with unique phenomena driven by heterogeneous components....
The Controlled, Site-Isolated Synthesis of Polyelemental Nanostructures in Polymer Nanoreactors Pengcheng Chen Polyelemental nanoparticles are an attractive class of materials due to their potential applications, which span the fields of catalysis, plasmonics, electronics, magnetics, targeted drug delivery, and bio-imaging. However, conventional synthetic methods for such structures are limited, especially when...
Increasing industrialization and the resulting negative environmental impacts highlight the need to develop alternative renewable energy sources. The Sun is a massive source and organic solar cells are a growing field of study. As new materials are synthesized, the efficiencies of organic solar cells continue to grow, but without an...
Electrostatic interactions mediated by ionic environments play a central role in physical processes across materials science, chemistry and biology. Key biological phenomena, such as the condensation and packaging of DNA, ion transport across cellular membranes and the enzymatic action of proteins, rely on the complex interplay between nanoscale electrostatic, osmotic...
To relate the mechanical responses of hard-soft copolymer systems with their microstructures, a coarse-grained molecular dynamics (CGMD) approach is employed. With the generic bead-spring polymer model mapped from atomistic simulations, this dissertation first studies the morphology of structures with various hard-soft compositions and interactions between hard beads. Following that, this...