Physical Sciences and Mathematics Commons^™

Multiscale Modeling Of Morphology And Proton/Ion Transport In Electrolytes, Zhenghao Zhu

Doctoral Dissertations

Understanding structure-function relationships in electrolytes is essential for advancing energy conversion and storage. This dissertation employs multiscale modeling and simulations to study the morphology and proton/ion transport in various electrolytes for electrochemical systems, including anion exchange membranes (AEMs), protic ionic liquids (PILs), pure phosphoric acid (PA) and aqueous acid solutions, ionic liquids (ILs), and polymerized ionic liquids (polyILs).

Mesoscale dissipative particle dynamics (DPD) simulations were employed to study the hydrated morphology of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS)-based AEMs. The results indicate that the choice of the functional group moderately affects the water distribution and has little influence on the …

Utilizing Phylogenetic And Geochemical Techniques To Examine Echinoderms Through Time, Maggie Ryan Limbeck

Doctoral Dissertations

Understanding biotic changes through Earth’s history has been the goal of paleobiology since the inception of the field. Advances in science and technology have progressed allowing us to reassess old questions and new questions that could have not been addressed without these new methods. Echinoderms (sea stars, sea urchins, etc.) appear in the fossil record during the early Cambrian and are still abundant in marine ecosystems today. This persistence through time has made echinoderms model organisms to answer questions about Earth’s past and present. Despite this role as a model organism there are many questions that remain with respect to …

Late Paleozoic Ophiuroid Biodiversity Based On A Diverse Fauna From The Indian Springs Shale Member Of The Big Clifty Formation, Sulphur, Indiana, Usa, Nicholas Scott Smith

Masters Theses

Ophiuroids (brittle stars and basket stars) are a diverse echinoderm group (i.e. star fish, sea urchins, and sea lilies) found in almost all marine environments and often major components of seafloor communities. Originating in the early to middle Devonian, the group quickly diversified and is today the most species rich echinoderm clade. Unfortunately, our knowledge of their diversity and evolutionary pathways during the Late Paleozoic has been understudied leaving a large gap in our understanding of their true biodiversity. This can be attributed to study methods and a poor understanding of Paleozoic ophiuroid skeletal morphology. Ophiuroid skeletons are composed of …

Preparation And Characterization Of Thermodynamically Controlled Polymer Nanocomposites, Jiadi Hou

Masters Theses

The mechanical and physical properties of polymeric materials can be greatly improved by adding nanoscale additives. To mediate the dispersion of nanoparticles in polymers, it is often necessary to modify their surfaces to prevent aggregation. While polymer nanocomposites system consisting of homopolymer-grafted nanoparticles are well understood, copolymer-functionalized nanoparticles are less well understood but provide additional ways to alter dispersion through the use of chemically different comonomers. In this thesis, polystyrene nanocomposites blended with copolymer-grafted nanoparticles were prepared and studied. The particular comonomers used were methyl methacrylate and cyclohexyl methacrylate, which provides miscibility with polystyrene. Polymers with varying comonomer ratios were …

Correlating Morphology To Performance In Conjugated Polymer Nanocomposite Thin Films, Siddharth Pradhan

Masters Theses

The morphology and performance of thin films that consist of conjugated polymers and nanoparticles are investigated in this thesis. In the first system, the morphology of the nanocomposite that consists of low band gap alternating copolymers with a methano-fullerene are determined by neutron scattering and correlated to their photovoltaic performance as polymer solar cells. These results show that the conjugated alternating copolymers have high miscibility relative to other conjugated polymers. The analysis of the scattering data shows that the morphology of the conjugated polymer-fullerene bulk heterojunction can be described as the formation of aggregates on two length scales. Important parameters …

The Role Of Non-Bonding Interactions And Bonding Schemes In The Structure And Properties Of Multi-Component Polymer Systems, Caleb Will Dyer

Doctoral Dissertations

This dissertation addresses three aspects of multi-component polymer systems. Chapter 2 details work on understanding the effect of precise polymeric structure on the phase behavior of blends containing cellulose acetate chains with different levels of acetate substitution. The difference in degree substitution (Delta DS) between the two components in the blend is systematically changed from .06 to .63, where each blend is found to be partially miscible. The samples containing higher acetate content demonstrate decreased miscibility as Delta DS increases. The sample with the most hydroxyl groups, however, has greater miscibility than samples of similar Delta DS, but fewer hydroxyl …

Synthesis, Characterization And Self-Assembly Of Amphiphilic Block Copolymers, Xiaojun Wang

Doctoral Dissertations

This dissertation presents a review on state-of-the-art research of well-defined charged block copolymers, including synthesis, characterization, bulk morphology and self-assembly in aqueous solution of amphiphilic block polyelectrolytes. In Chapter 1, as a general introduction, experimental observations and theoretical calculations devoted towards understanding morphological behavior in charged block copolymer systems are reviewed along with some of the new emerging research directions. Further investigation of charged systems is urged in order to fully understand their morphological behavior and to directly target structures for the tremendous potential in technological applications. Following this background, in Chapters 2, 3, 4 and 5 are presented the …