Melanin is a functional biopolymer most commonly associated with human skin pigmentation, where it serves as a radiation protection agent, shielding us from the harmful effects of UV radiation. However, melanin is also present in human ears, eyes, hair, and brains, serving a variety of functions. In fact, melanin...
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...
Superconductivity is a fascinating manifestation of quantum mechanics on a macroscopic scale that has led to greater insights of the strongly correlated physics of a large number of interacting electrons ever since its discovery $\sim$ 100 years ago in elemental Hg. The unconventional superconductors that are based on uranium offer...
At its core, the purpose of microscopy is to make objects and their underlying structures visible under high magnification. With the remarkable progress of electron microscopy, the sub-micron “high” magnification of light microscopy has been completely refashioned to encompass subatomic length scales. Unfortunately, higher-magnification does little to negate existing interpretability...
Plasmonic nanoparticles have very large absorption cross sections and can concentrate the local density of photon states on the nano scale. When they are coupled to molecules or semiconductor nanocrystals and form different hybrid nanostructures, various light-matter interaction processes can be significantly enhanced or manipulated, including optical responses like fluorescence...
Exploratory phase stability analysis in Materials Science has two primary goals: (a) Characterizing the evolution of the materials single phase field in composition space to identify solubility and electronic dopability limits and (b) Accelerated prediction of new phases of technological importance. In this thesis we reorganize defect theory --- the...
Colloidal crystal engineering with DNA offers new opportunities for materials scientists to build and program the structures of superlattices beyond what can be accomplished in Nature with atomic crystal lattices. Thus far, such materials primarily have been studied for their optical properties due to the insulating nature of the DNA...
The crystal structure of chalcogenides can vary from simple, ubiquitous structures of rock salt and zinc blende to unique structure types from the intricate packing of complex anionic building blocks. Exploratory synthesis and structural studies of novel chalcogenides containing these complex anions will augment the understanding of bonding in chalcogenides....
The era of quantum information science (QIS) can usher revolutionary new capabilities ranging from quantum computation to quantum sensing. At the core of these technologies is the fundamental unit of QIS, the quantum bit or qubit. The power of qubits over their classical counterparts lies in their ability to be...
Two-step, solar thermochemical water splitting using nonstoichiometric oxides has emerged as an attractive approach for large-scale hydrogen production. Perovskite-structured oxides, with their wide tunability, offer the potential for high fuel productivity at moderate operating temperatures. Given the vast chemical space, the materials development effort is carried out here in combination...
The heart of computational materials science lies in providing fundamental insights and understanding of materials behavior and properties across different scales. The significance of this task is highlighted by the Materials Genome Initiative and the emergence of computational tools and frameworks such as materials by design, microstructure sensitive design, and...
The successful isolation of graphene marked the advent of two-dimensional (2D) materials. Their atomically thin structures enable unprecedented electrical, optical, and mechanical properties, which have triggered significant research interests in the past decade. For instance, they are promising candidates for the fabrication of flexible electronics, biological sensors, battery electrodes, and...
Sea urchins are virtuosi of biomineralization, the process by which organisms build mineralized tissues. The embryonic animal exemplifies this with the formation of its endoskeletal spicule. The primary mesenchyme cells (PMCs) undertake spicule synthesis, which involves deposition of the initial granule, elongation of the spicule, and several choreographed changes...
A series of theories and models are developed and used to investigate the growth of protective oxide films on metal and alloy surfaces for cases in which Wagner's classical model of oxidation does not hold. First, irreversible thermodynamics is applied to formulate a model for the outward growth of rocksalt...
Nucleic acids not only are the building blocks of life but also a class of attractive macromolecular therapeutics. However, the delivery of therapeutic oligonucleotides into cells has been a major challenge due to their large size and highly negatively charged backbone. Spherical nucleic acids (SNAs) are a class of emerging...
Part I: Design of Photo-Responsive Molecules towards Biomedical ApplicationsThe use of light to control systems provides numerous advantages such as spatiotemporal precision, non-invasive penetration, and precise energy input. Specifically, molecules that undergo photoinduced cleavage, photoremovable protecting groups (PPGs) have emerged as an active area of research due to their broad...
Non-covalent and ion-specific interactions in the context of charged polymers are ubiquitous in nature and in synthetic applications. For example, mussels utilize metal-coordinate bonds to form tough underwater adhesion to a wide range of substrates. The sandcastle worm uses coacervation of oppositely charged polymers to build robust structures for self-defense....
Surface patterns that can reconfigure under external stimuli are important for tailoring diverse properties such as surface adhesion, optical transmittance, and wettability depending on the feature size and orientation. Wrinkling a stiff skin layer on a pre-strained elastomer substrate has emerged as a method to create responsive structures without using...
The complex structure of typical heterogeneous catalysts, where nanoparticles of active material are dispersed onto the surface of a thermally stable support with a high surface area, complicates the understanding of how the support can affect the resulting catalyst structure and properties. Using well-faceted and shape-controlled oxides as supports would...
The idea that structure determines the properties of a material is a powerful concept in chemistry and in all fields in which chemistry is important, including engineering, medicine, and materials science. My research aims to better understand the structure-property relationships of a class of materials known as metal–organic frameworks (MOFs)....