Chemistry Commons^™

Using Two Different Approaches For The Creation Of Poly(3-Hexylthiophene)-Functionalized Siloxane Nanoparticles For Organic-Based Solar Cells, Nicholas A. Wright

Mahurin Honors College Capstone Experience/Thesis Projects

Poly(3-hexylthiophene)-functionalized silsesquioxane nanoparticles were prepared from direct hydrolysis and condensation of P3HT-silane precursor using “grafting from” and “grafting to” methods. The size, shape, and surface morphology of these polymer grafts particles were visualized using transmission electron microscopy and scanning electron microscopy. Their compositions confirmed by FTIR, thermogravimetric analysis and elemental analysis. The XRD analysis revealed the polymer orientation and packing pattern of the nanocomposites, indicating the highly ordered lamella stacks of P3HT polymer chains. The photovoltaic performance of the blends of P3HT-nanohybrid with the C60 derivative PCBM was evaluated upon annealation in different temperatures, ranging from 50°C to 150 °C. …

New Dual Initiators For Polyisobutylene-Based Block And Star Polymers, Yaling Zhu

Dissertations

Polyisobutylene (PIB), available solely by living carbocationic polymerization (LCP), is a commercially important polymer with excellent thermal stability, good flexibility and extraordinary impermeability to gases. Due to these attractive properties, coupling PIB to other polymer blocks is expected to result in new and useful products. Two types of new dual initiators possessing initiating sites for both LCP and atom transfer radical polymerization (ATRP), have been designed for the preparation of AB linear and A2B miktoarm star copolymers, where A is PIB-based block copolymer that grows cationically and B is polyacrylate or other radically-derived polymer block, without intermediate modification.

Mono-cationic mono-radical …

Surface Modifications Of Capillary-Channeled Polymer (C-Cp) Fibers For Applications In Highly Selective Separations, Jennifer Pittman

All Dissertations

High Performance Liquid Chromatography (HPLC) is a key component in the purification and separation of biological samples. Stationary phases in HPLC are generally silica based porous particles or monoliths designed with high surface area and high capacities in mind. However, in the field of macromolecule separations, specifically proteins, the porous based stationary phases have inherent issues that include slow mass transfer, high operating back pressures, and analyte carryover. Recent research has looked to non-porous polymeric materials as stationary phases in HPLC to overcome these challenges. Specifically, fibrous based polymer stationary phases exhibit significant benefits for macromolecules that include improved mass …

1. Improving The Yield Of Biodiesel From Microalgae And Other Lipids. 2. Studies Of The Wax Ester Biosynthetic Pathway And Potential Biotechnological Application, Bradley D. Wahlen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The production of biofuels and oleochemicals from renewable sources offers an opportunity to reduce our dependence on fossil fuels. The work contained in this dissertation has focused on developing and improving methods for the production of biodiesel from non-traditional feedstocks and understanding biosynthetic pathways that result in the production of oleochemicals and fuels.

Pure vegetable oil can account for 70-80% of the total cost of biodiesel production. Many low-cost oils contain high amounts of free fatty acids, which are unsuitable for base-catalyzed transesterification. Herein an approach is described that efficiently accomplishes the simultaneous esterification and transesterification of both free fatty …

Ph-Responsive Polymers For Biosurfaces: An Investigation Of Solution Properties And Surface Modifying Performance, Yuhong Wei

Master's Theses

Gantrez® copolymers are used widely in the personal care industry, but their mechanisms of interaction with dental surfaces are poorly understood. In this study, we determined a number of the solution and polymer properties that control deposition, adsorption and adhesion in Gantrez® polymer aqueous solutions to model dental surfaces. QCM studies specifically showed that polymer adsorption to model hydroxyapatite surfaces occurred only in solutions with polymer concentration above c*. Adsorption and adhesion was greater in solutions of higher pH, where greater charge density along the polymer backbone was expected. For films prepared via spin-coating onto mica surfaces, addition of surfactants …

Challenging Disciplinary Boundaries In The First Year: A New Introductory Integrated Science Course For Stem Majors, Lisa Gentile, Lester Caudill, Mirela Fetea, April L. Hill, Kathy Hoke, Barry Lawson, Ovidiu Z. Lipan, Michael Kerckhove, Carol A. Parish, Krista J. Stenger, Doug Szajda

Department of Math & Statistics Faculty Publications

To help undergraduates make connections among disciplines so they are able to approach, evaluate, and contribute to the solutions of important global problems, our campus has been focused on interdisciplinary research and education opportunities across the science, technology, engineering, and mathematics (STEM) disciplines. This paper describes the mobilization, planning, and implementation of a first-year interdisciplinary course for STEM majors that integrates key concepts found in traditional first-semester biology, chemistry, computer science, mathematics, and physics courses. This team-taught course, Integrated Quantitative Science (IQS), is half of a first-year student’s schedule in both semesters and is composed of a double lecture and …

Biologically-Derived Dye-Sensitized Solar Cells: A Cleaner Alternative For Solar Energy, Erika S. Falsgraf

Pomona Senior Theses

This project employs the biological compounds hemin, melanin, and retinoic acid as photoactive dyes in dye-sensitized solar cells (DSSCs). These dyes are environmentally and economically superior to the standard ruthenium-based dyes currently used in DSSCs because they are nontoxic and widely available. Characterization by linear sweep voltammetry yielded averaged maximum overall conversion efficiency values of 0.059% for retinoic acid, 0.023% for melanin, and 0.015% for hemin. Absorption spectra of hemin and retinoic acid suggest that they would complement each other well when used in tandem in one cell because hemin has a secondary maximum absorption peak at 613nm and retinoic …

Development Of An Assay To Screen For Novel Proteins From Bacillus Thuringiensis With Antibacterial Activity, Auriole T. Tamegnon

Theses and Dissertations - UTB/UTPA

Bacillus thuringiensis (Bt) produces the non specific Cyt protein and the specific Cry protein. Past research has shown these proteins are toxic to insects, red blood cells, cancer cells, and some bacteria. While many antibacterial substances are known to exist, efforts to find new ones still continue. In this project we used Bt 6-2-56 (containing a novel filament associated parasporal body which appears non-toxic to insects and protozoan) and Bt 4Q13 (which has been shown to have activity against E. coli and S. aureus) to develop a simple, easy, scalable assay in a 96 well Microtitre plate to look for …

Modern Approaches For Multifunctional Hydrolyzying Thiol-Ene Networks, Nicole Marie Mackey

Dissertations

Marine fouling has been an expensive and time-consuming process for navies and fishermen by the accumulation of marine algae and animals on artificial surfaces. Many coatings have been proposed to combat marine fouling in efforts to extend the lifetime of objects immersed in sea water. However, all coatings tested have either failed to resist fouling for a significant length of time or have released toxins into the environment. We have investigated an environmentally friendly approach to address the problem of marine fouling through the synthesis and preparation of a biocidal and a self-polishing coating. Both novel monomers were prepared containing …

Molecular Network Development Of A Thermosetting Epoxy-Amine Polymer, Christopher Michael Sahagun

Dissertations

i ABSTRACT MOLECULAR NETWORK DEVELOPMENT OF A THERMOSETTING EPOXY-AMINE POLYMER by Christopher Michael Sahagun May 2012 Epoxy-amine resins find wide application as the matrix material of high performance polymer composites due to their favorable mechanical properties, thermal properties and solvent stability. These properties are derived from the complicated, highly crosslinked molecular network that is characteristic of these thermoset polymers. The connectivity of the molecular network has a strong influence on the physical performance of the finished part. Non-homogeneity in the network structure can degrade these favorable properties through the introduction of low-energy pathways for solvent penetration or fracture propagation. This …

Surface, Bulk, And Rheological Properties Of Polyhedral Oligomeric Silsesquioxane/High Density Polyethylene Nanocomposites, Robert Douglas Cook Jr.

Dissertations

In the formulation of high performance nanocomposites, control of miscibility and dispersion of filler material through a polymer matrix is of utmost importance. Due to their inorganic nature most nanofillers are insoluble in polymers, leading to costly/complicated surface modification as a primary means of increasing miscibility and interaction with organic matrices. Polyhedral oligomeric silsesquioxane (POSS) nanostructured chemicals offer an attractive alternative to conventional nanofillers. Due to their hybrid organic-inorganic nature, POSS has the potential to be tailored for miscibility in a wide range of organic matrices not by chemical surface modification but through modification of the molecular structure of the …

A Bisphenol-A-Based Resin System That Cures Via Triazole Ring Formation For Marine Composite Applications, Irene Elizabeth Gorman

Dissertations

Large composite panels, such as those utilized in marine applications, cannot be economically cured in an autoclave. For these structures the elevated temperatures necessary to achieve high crosslink density must come from the curing reaction itself. We are developing a resin system that cures via triazole ring formation (cycloaddition reaction of azides with terminal alkynes) instead of the traditional oxirane/amine reaction. The high exothermicity of the azido/alkyne reaction is expected to yield higher extents of reaction under ambient-cure conditions, making the resin system potentially suitable for "out-of-autoclave" curing processes. This work was conducted through a multi-tiered approach involving synthesis, kinetic …

Arsenic Contamination In Groundwater In Vietnam: An Overview And Analysis Of The Historical, Cultural, Economic, And Political Parameters In The Success Of Various Mitigation Options, Thuy M. Ly

Pomona Senior Theses

Although arsenic is naturally present in the environment, 99% of human exposure to arsenic is through ingestion. Throughout history, arsenic is known as “the king of poisons”; it is mutagenic, carcinogenic, and teratogenic. Even in smaller concentrations, it accumulates in the body and takes decades before any physical symptoms of arsenic poisoning shows. According to the World Health Organization (WHO), the safe concentration of arsenic in drinking water is 10 µg/L. However, this limit is often times ignored until it is decades too late and people begin showing symptoms of having been poisoned.

This is the current situation for Vietnam, …

Regioselective Synthesis Of Tetraalkynylarenes By Consecutive Dual Sonogashira Coupling Reactions Of The Bis(Triflate) Of 4,5-Diiodobenzene-1,2-Diol, Thomas J. Fisher, Patrick H. Dussault

Patrick Dussault Publications

Abstract The regioselective synthesis of nonsymmetric tetraalkynylarenes has been readily achieved through consecutive sets of Sonagashira cross-coupling reactions of the bis(triflate) derivative of 4,5-diiodobenzene-1,2-diol. The initial coupling reactions proceeded with nearly complete selectivity for the reaction at the Ar–I linkages. Subsequent coupling reactions at the Ar–OTf linkages were efficiently conducted. The tetraalkynylarene products are of interest as components of organic molecular materials.

Production Of Biodiesel From Oleaginous Organisms Using Underutilized Wastewaters, Valerie Godfrey

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As part of the BioEnergy Team at Utah State Univeristy, my research objectives have been centered around the common theme of innovating new methods and
technology for producing biological compounds and, by means of chemical conversion and/or extraction, isolating new forms of biodiesel available for transportation fuel.
Within the broad scope of this project, I focused on the replacement of freshwater in cultivating such biological systems with wastewaters. If accomplished and correctly
applied, such research would reduce the environmental impact of biodiesel production by reducing the demand for freshwater. It also would reduce production costs by reducing the amount of …

Structural And Mechanistic Investigations Of Phosphothreonine Lyase Class Of Enzymes, Alok Gopalkrishna Shenoy

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Phosphorylation and dephosphorylation are a highly pervasive mechanism in biology that is used by the cell to modulate enzymes and proteins. The presence of a phosphate group can activate or deactivate an enzyme. The phosphate group is linked to a protein by a phosphoester bond that is known to be highly stable in cytoplasmic pH range. Thus the breaking and formation of these bonds need to be effected by enzymes.

Recent discovery of the activity carried out by certain virulence related proteins (OspF released by Shigella and SpvC released by Salmonella) have resulted in a necessity to create a new …

The Kinetics And Mechanisms Of Some Fundamental Organic Reactions Of Nitro Compounds, Zhao Li

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

In chemistry, kinetics is the study of the rates of chemical reactions. A reaction mechanism describes in detail exactly what takes place at each stage of an overall chemical reaction from reactants to products. The work outlined in this dissertation was carried out in order to find out the true mechanisms of some fundamental organic reactions of nitro compounds by means of a series of novel kinetic techniques and analysis methods.

The target reactions include (1) the proton transfer reactions of nitroalkanes and (2) the aromatic nucleophilic reactions of trinitroarenes, both of which are undeniably among the most elementary and …

The Mechanisms Of Hydride Exchange, Organic Combination And Displacement Reactions, Weifang Hao

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The primary aim of this dissertation was to seek the answer to the question: “Is the single transition-state model appropriate for the fundamental reactions in organic chemistry?” The goal was accomplished by performing enormous kinetic data collection and detailed mechanistic analysis on several typical fundamental organic chemical reactions. Three new methodologies for differentiating between a simple one-step and complex multi-step mechanism were developed and extensively confirmed during the application in the kinetic studies of all of the reaction discussed in this dissertation. The three methods consist of (1) half-life dependence of kapp, (2) sequential linear pseudo-first-order correlation, and (3) revised …

Exploration Of The Chemistry Of Alkynes And Selectfluor : Search For Cytotoxic Agents From The Amazonian Rainforest., Zhuang Jin

Electronic Theses and Dissertations

Vicinal dithioethers and alkenyl thioethers were synthesized under environmentally friendly conditions using alkyne and thiol in water. Alkynes were also used to develop a multibond-fonning reaction that fonned cyclic ketones or ketoesters through a goldcatalyzed intramolecular oxygen transfer isomerization of 2-alkynyl-l ,5-diketones or 2- alkyny 1-5 -ketoesters. The investigation of Selectfluor chemistry yielded a highly stereoselective synthesis of fluoroalky (E)-a,ß-unsaturated ketones from allenyl esters, through a gold-catalyzed rearrangement that produced an intennediate dienyl ester. When Selectfluor was combined with copper, it produced two oxidative systems, F-TEDA-BF4 and F-TEDAPF 6, both of which efficiently converted amides into imides at room temperature …

Challenging Disciplinary Boundaries In The First Year: A New Introductory Integrated Science Course For Stem Majors, Lisa Gentile, Lester Caudill, Mirela Fetea, April L. Hill, Kathy Hoke, Barry Lawson, Ovidiu Z. Lipan, Michael Kerckhove, Carol A. Parish, Krista J. Stenger, Doug Szajda

Biology Faculty Publications

To help undergraduates make connections among disciplines so they are able to approach, evaluate, and contribute to the solutions of important global problems, our campus has been focused on interdisciplinary research and education opportunities across the science, technology, engineering, and mathematics (STEM) disciplines. This paper describes the mobilization, planning, and implementation of a first-year interdisciplinary course for STEM majors that integrates key concepts found in traditional first-semester biology, chemistry, computer science, mathematics, and physics courses. This team-taught course, Integrated Quantitative Science (IQS), is half of a first-year student’s schedule in both semesters and is composed of a double lecture and …

A Fast Response Highly Selective Probe For The Detection Of Glutathione In Human Blood Plasma, Yixing Guo, Xiaofeng Yang, Lovemore Hakuna, Aabha Barve, Jorge O. Escobedo, Mark Lowry, Robert M. Strongin

Chemistry Faculty Publications and Presentations

A fluorescent probe for glutathione (GSH) detection was developed. Our study indicates a possible mechanism which couples a conjugate addition and micelle-catalyzed large membered ring formation/elimination sequence. This method enables excellent selectivity towards GSH over other biological thiols such as cysteine (Cys) and homocysteine (Hcy). The proposed method is precise with a relative standard deviation (R.S.D) lower than 6% (n = 3) and has been successfully applied to determine GSH in human plasma with recoveries between 99.2% and 102.3%.

Cuprate Mediated Allylic Substitutions On Vinylepoxides And Conjugate Additions On 2-Pyridones, Yaxin Huang

All Dissertations

Regioselective control in allylic substitution reactions of vinylepoxides is difficult due to the competition between SN2- substitution and SN2'- allylic substitution pathway. Although excellent SN2'/SN2- and anti/syn- ratios were achieved by CuCN derived organozinc cuprates on 4,5-epoxy-2,3-enoates, application of this methodology to the vinylepoxide, trans-1-(tert-butyldimethylsilyloxy)-2,3-epoxy-4-hexene, is explored. Dialkyzinc reagents mediated by catalytic amounts of CuCN provide excellent regio-(SN2'/SN2) and diastereo-(olefinic E/Z and anti/syn-) selectivity with n-Bu, Et and t-Bu ligands, while reduced E/Z and SN2'/SN2- ratios were achieved with aromatic ligands (e.g., furyl and Ph). The assignment of regio- and stereoisomers were achieved by alternative syntheses of the authentic compounds. …

Generation Of Molecular Complexity From Cyclooctatetraene Using Dienyliron And Olefin Metathesis Methodology, Mohamed F. El-Mansy, Anobick Sar, Subhabrata Chaudhury, Nathaniel J. Wallock, William A. Donaldson

Chemistry Faculty Research and Publications

Transformation of the simple hydrocarbon cyclooctatetraene into a variety of polycyclic skeletons was achieved by sequential coordination to iron, reaction with electrophiles followed by allylated nucleophiles, decomplexation and olefin metathesis.

Co Adsorption On Supported Gold Nanoparticle Catalysts: Application Of The Temkin Model, Christopher J. Pursell, Bert D. Chandler, M. Manzoli, F. Boccuzzi

Chemistry Faculty Research

The adsorption of CO on the supported gold nanoparticle catalysts Au/TiO2, Au/Fe2O3, and Au/ZrO2 was examined using infrared transmission spectroscopy to quantify the isobaric CO coverage as a function of temperature. The Temkin adsorbate interaction model was then applied to account for the adsorption behavior. To test the general applicability of the Temkin model, this treatment was also applied to three data sets from the literature. This included another real-world catalyst and two model catalysts. All data sets were accurately represented by the Temkin adsorbate interaction model. The resulting thermodynamic metrics are consistent with previous determinations and reflect a particle …

Self-Assembled And Flow Induced Nano-Structures In Polymer Nanocomposites, Dilru Ratnaweera

All Dissertations

Distribution of nanoparticles (NPs) in polymers and role of NPs in modifying the structure of the polymeric matrices were studied using X-ray diffraction, neutron scattering, neutron reflectivity and atomic force microscopy techniques. Dispersion of NPs in polymers is challenging due to the aggregation tendency of NPs and inherent mixing challenges of polymer. Several strategies were used to control the NP distribution in polymers, including 'smart blending' and tailoring the interactions of the polymers.
In smart blending chaotic flow fields were used to disperse and orient montmorillonite NPs in homopolymer melt of polyamide 6 (PA6). The roles of duration of chaotic …

Finding A New Continent Versus Mapping All The Rivers: Recognition, Ownership, And The Scientific Epistemological Development Of Practicing Scientists And Engineers, Andrea Verdan

All Dissertations

Maintaining our nation's standing as a leader of innovative and premier science and engineering research requires that those on the trajectory of these careers receive both rigorous and exceptional training. In addition to educating students in the content knowledge of these disciplines, it is also necessary to train them in the professional skills associated with being competent and conscientious scientists and engineers. In the attempts to understand the best strategies to teach these skills, research during the past few decades has shown a steadily increasing interest in improving the scientific literacy of students in science and engineering disciplines. Researchers agree …

On The Electronic Spectroscopy Of Closed Shell Cations Derived From Resonance Stabilized Radicals: Insights From Theory And Franck-Condon Analysis, T. P. Troy, S. H. Kable, T. W. Schmidt, Scott A. Reid

Chemistry Faculty Research and Publications

Context. Recent attention has been directed on closed-shell aromatic cations as potential carriers of the diffuse interstellar bands. The spectra of mass-selected, matrix-isolated benzylium, and tropylium cations were recently reported. The visible spectrum of benzylium exhibits a large Franck-Condon (FC) envelope, inconsistent with diffuse interstellar band carriers.

Aims. We perform a computational analysis of the experimentally studied benzylium spectrum before extending the methods to a range of larger, closed-shell aromatic cations to determine the potential for this class of systems as diffuse interstellar band carriers.

Methods. Density functional theory (DFT), time-dependent ((TD)DFT), and multi-configurational self-consistent field second-order perturbation theory (MRPT2) …

Rationalizing Structure, Stability, And Chemical Bonding Of Pure And Doped Clusters Isolated And Solvated Multiply Charged Anions, And Solid State Materials, Alina P. Sergeeva

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chemistry is the study of materials and the changes that materials undergo. One can tune the properties of the known materials and design the novel materials with desired properties knowing what is responsible for the chemical reactivity, structure, and stability of those materials. The unified chemical bonding theory could address all these questions, but we do not have one available yet. The most accepted general theory of chemical bonding was proposed by Lewis in 1916, though Lewis’s theory fails to explain the bonding in materials with delocalized electron density such as sub-nano and nanoclusters, as well as aromatic organic and …

Structural And Functional Characterization Of The Essential Rna Helicase Mtr4, Ryan N. Jackson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

To insure the integrity of nuclear RNA, the eukaryotic cell employs surveillance systems that identify and degrade RNAs that are detrimental or unneeded. The failure of RNA surveillance systems can lead to neurodegenerative disease states and cancer. The essential RNA helicase Mtr4 is required for the degradation and processing of several nuclear RNAs. To further the understanding of RNA surveillance and processing in eukaryotes, Ryan Jackson of the Department of Chemistry and Biochemistry at Utah State University has determined the molecular structure of Mtr4 and has used this structure to interrogate Mtr4 function biochemically. The structure revealed that Mtr4 contains …

A Density Functional Theory And Laser Flash Photolysis Investigation Of Carbofuran Photodegradation In Aqueous Medium, A. Atifi, M. Talipov, H. Mountacer, Michael D. Ryan, M. Sarakha

Chemistry Faculty Research and Publications

Density functional theory (DFT) approach was used to study the photodegradation of Carbofuran in aqueous medium. This computational method enables us to assign the electronic transitions and interpret the dissociative behavior upon irradiation based on a thermodynamical analysis of the bond dissociation energies (BDE) of Carbofuran. According to these calculations, phenoxy C---O bond appears weaker than the C---N bonds. Hence, it was predicted that the photodegradation of Carbofuran should occur with an initial homolytic dissociation of the C---O bond of the carbamate moiety. Laser Flash Photolysis (LFP) results clearly indicate the formation of the phenoxyl radical, which support the outcome …