Physical Sciences and Mathematics Commons^™

Hierarchical Conjugated Polymer Systems Prepared By Controlled Chain-Growth Polymerization, Chunwa Peter Kei

LSU Doctoral Dissertations

π-Conjugated polymer materials may have a significant economic impact on society by providing means for designing affordable, flexible, and portable organic electronic devices. Their successful commercialization will depend on major scientific advancements, which will challenge human society to seek out ever more detailed and fundamental processes to command. Controlled polymerization affords such a power; allowing for the design of meticulous and precisely defined systems granting detailed insight into structure-property relationships in the polymer materials and bettering understanding of novel physical phenomena.

This dissertation primarily focuses on development and preparation of well-defined hierarchically organized macromolecular systems. The novel chain-growth polymerization methodologies …

Visible Light And Electron Transfer Chemistry For O-Glycosylation And Remote Hydroxylation, Mark Louis Spell

LSU Doctoral Dissertations

This dissertation focuses on the synthesis of dauer pheromone analogs for biological evaluation, the development of visible light promoted O-glycosylation methods and the development of an Ir(ppy)3 catalyzed C-H hydroxylation method. Chapter 1 describes the synthesis of dauer pheromone analogs. C.elegans is a small nematode that enters a dauer stage when encountering unfavorable environmental conditions. The dauer stage is initiated by the nematodes chemosensation of the dauer pheromone caused by the down regulation biochemical pathways TGF-â and IGF-1. These biochemical pathways are also seen in Homo Sapiens and play a role in a number of biological processes. Understanding how these …

Surface Studies Of Organic Thin Films Using Scanning Probe Microscopy And Nanofabrication, Venetia Denae Lyles

LSU Doctoral Dissertations

Porphyrins and metalloporphyrins have unique chemical and electronic properties and thus provide useful model structures for nanoscale studies of the role of chemical structure for electronic properties. Porphyrins have been proposed as viable materials for molecular-based information-storage devices, gas sensors, photovoltaic cells, organic light-emitting diodes and molecular wires. The function and efficiency of porphyrins in devices is largely attributable to molecular architecture and how the molecules are self-organized. Modifications of the porphyrin macrocycle, peripheral groups or bound metal ions can generate a range of electrical, photoelectrical or magnetic properties. The conductive properties are greatly influenced at the molecular level by …

Wet And Dry Aging Of Polymer-Asphalt Blends: Chemistry And Performance, Ionela Chiparus Glover

LSU Doctoral Dissertations

A PG 76-22 Polymer Modified Asphalt Cement composition was subjected in the laboratory to accelerated aging using both a standard Thin Film Oven Test and a Pressure Aging Vessel. Conditions simulating wet atmospheres (PAV in saturated water vapors) as well as very long service terms (multiple dry and wet PAV operations) were studied. A Rotating Cylinder Aging Test has been employed as an alternate asphalt aging technique using the same PMAC composition in order to observe the initial phases of the oxidative aging process. The data provided by this technique was correlated with the actual aging in the field of …

Modeling Longleaf Pine (Pinus Palustris Mill) Wood Properties Using Near Infrared Spectroscopy, Brian Kipling Via

LSU Doctoral Dissertations

This research demonstrated model development for important wood properties using near infrared spectroscopy (NIR); it considered the effect of outside sources of error, and the ability of NIR to measure fiber morphology. Strength, stiffness, and density were successfully modeled from wood samples taken throughout 10 longleaf (Pinus palustris Mill) trees. Principal components and multiple linear regression were compared for performance in prediction of density, strength, and stiffness. I found both modeling techniques to yield similar prediction accuracies. However, I found that density could be estimated through Beer-Lambert’s law since the absorbance at all wavelengths increased with density. Also, 5 of …