Physical Sciences and Mathematics Commons^™

Dynamic Metal-Ligand Interactions In Semiconducting Π-Conjugated Materials, Peter Blake Joseph St Onge

Electronic Theses and Dissertations

Over the years, the development of materials has seen a vast amount of expansion into a variety of disciplines which have demonstrated usefulness in a large span of applications. One of these new and developing themes is the use of metals and ligands which are incorporated into polymers to modify their properties, which can enable different desired properties. Incorporation of metal-ligand complexes in materials chemistry has proven to be an area of rising interest, however, many of these interactions and systems remained completely unexplored. Understanding the key fundamental principles of how these materials can be changed and modified through metal-ligand …

Exploring Soybean Oil-Based Polyol And Effect Of Non-Halogenated Flame Retardants In Rigid Polyurethane Foam, Sahithi Kondaveeti

Electronic Theses & Dissertations

To address the increasing demand for sustainable biomaterials due to the depletion of fossil fuel resources and growing environmental concerns, a new type of biodegradable and environmentally friendly rigid polyurethane foam (RPUF) has been synthesized. These foams are derived from chemically modified soybean oil-based polyol obtained from soybean oil by epoxidation followed by a ring-opening reaction. Polyurethane foam is generally used in construction, furniture, and automobile industries but is highly flammable and releases toxic gases and smoke during combustion. In this study, a highly efficient synergistic effect halogen-free flame-retardant (FR) melamine salt, 2-carboxyethyl(phenyl)phosphinic acid melamine salt (CMA) was synthesized from …

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …

Precise Determination Of Charge Distributions In Electron Irradiated Polymers Via Pulsed Electroacoustic Measurements With Applications To Spacecraft Charging, Zachary Gibson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Understanding how charge builds up and moves around in materials that are highly insulating, such as dielectrics, is important for many applications from power transmission to spacecraft charging. The leading cause of issues in spacecraft due to interactions with the space environment is spacecraft charging. That is, the accumulation of charge on insulating materials leads to arcing and sparking aboard the spacecraft. The most critical charging occurs due to electrons in a particular energy range of 10-50 keV. Electrons with these energies can travel 1’s to 10’s of microns into relevant materials. To measure where the charge is embedded and …

Development Of Biomolecule Nanoparticle Conjugate For Targeted Delivery Of Therapeutics, Peidong Wu

Doctoral Dissertations

Delivery of therapeutics specifically to the disease site is the final goal for the field of drug discovery. Considerable efforts in understanding disease biology have contributed to identifying novel therapeutics such as small molecules, proteolysis targeting chimeras (PROTACs), peptides, proteins, and nucleic acids. However, improving their efficacy as well as minimizing their off-target toxicity remains challenging. Developing vectors that could not only efficiently encapsulate these therapeutics but also direct these therapeutics to the target site is a potential solution to address these challenges. In this dissertation, a block-copolymer-based nanoparticle platform has been developed optimized, and decorated with various kinds of …

Designing Polymers With Stimuli-Responsive Degradation For Biomedical Applications, Chuanfeng Li, Zhengyu Deng, Elizabeth R. Gillies

Chemistry Publications

Early biomedical applications of polymers were in areas such as joint replacements and often involved durable polymers. However, biodegradable polymers are increasingly being used to perform temporary functions such as drug delivery or supporting cells, after which they can break down and be eliminated from the body. Polymers that degrade specifically in response to stimuli offer additional opportunities to control when and where this degradation occurs, enabling enhanced functions such as site-specific drug release and the early detection of disease. In this article, we will discuss recent advancements in the design, preparation, and application of stimuli-responsive polymer degradation. In …

Expanding The Polymer Zwitterion Library – Novel Phosphonium-Based Polymer Zwitterions And Analogous Structures, Marcel U. Brown

Doctoral Dissertations

This dissertation encompasses the synthesis, characterization and application of novel polymer zwitterions that significantly expand the library of available zwitterionic polymers. Their facile synthesis is facilitated by the preparation of a novel functional sultone precursor molecule, which can be ring-opened by commercially available phosphine, amine and sulfide nucleophiles, affording phosphonium, ammonium or sulfonium sulfonate monomers, respectively. Most notably, this work describes the invention of phosphonium-based polymer zwitterions, establishing a new class of zwitterionic polymer structures with unique solution and interfacial properties. Furthermore, the incorporation of these phosphonium sulfonates into block copolymer architectures with conventional polymer zwitterions, and the resulting switchable …

On A Novel Approach To The Thermogravimetric Analysis Of Polymers: Polystyrene, Mircea Chipara, Karen Lozano, Dorina M. Chipara, Carlos Delgado, Victoria Padilla

Physics and Astronomy Faculty Publications and Presentations

A novel equation that describes the temperature dependence of the residual mass fraction (as determined by thermogravimetric analysis) is derived, assuming that the dependence of the residual mass fraction on temperature has a sigmoidal shape. The equation allows the estimation of the sigmoidal activation energy solely from the experimental data at a single heating rate. The consistency with the isoconversional approach and the relationship between the Ozawa and sigmoidal activation energies are reported. The equation was successfully tested by the thermal degradation of atactic polystyrene at various heating rates. Both the thermograms and their derivatives are analyzed in detail.

Functional Bottlebrush Polymer Additives For Thin Films And Coatings, Travis S. Laws

Doctoral Dissertations

Bottlebrush polymers are a class of highly branched polymers consisting of polymeric side chains that are densely grafted to a linear backbone. Their highly branched architecture results in surface enrichment across a broad range of materials. The goal of my research has been centered around the design of functional bottlebrush polymers and their use as surface active additives in blend films and coatings.

In the first chapter, we examine the segregation behavior of polystyrene bottlebrushes that are blended with linear polystyrene. We systematically vary the lengths of the bottlebrush backbone (Nb), side-chain (Nsc), and the linear matrix (Nm) in order …

Synthesis Of Fluorinated Monomers And Polymers For Various Applications, Cassandra J. Hager

All Dissertations

The world of industry utilizes a variety of polymers for various applications in many prominent fields. From electronics to food storage, the versatility of this class of chemistry has been widely proven. The Thrasher research group undertook a program dedicated towards the development of a library of fluorinated materials that focused on the synthesis and characterization of perfluoroalkoxy (PFA) copolymers of tetrafluoroethylene (TFE) and perfluoroalkyl trifluorovinyl ethers. One aim of the project was to improve upon the mechanical strength and wearability of commercial PFA resins by incorporating bulkier perfluoroalkoxy trifluorovinyl ether monomers into these copolymers. In addition to focusing on …

Functionalized 𝜹-Hexalactones (Fdhls): Bio-Derivable Monomers To Synthesize Renewable Polyester Thermoplastics, Atik Faysal

Electronic Theses and Dissertations

Most thermoplastics are made from limited fossil-fuel sources and these plastics have very deleterious impacts on the environment. Finding a renewable source to synthesize new thermoplastic polymers with tunable properties like biodegradability, heat resistance, and moisture resistance are ongoing research interests. Lignocellulosic biomass is a promising renewable feedstock for biobased monomers and polymers production. In this work, functionalized 𝛿-hexalactone (FDHL) monomers are hypothesized to be synthesizable from lignocellulosic sourced hydroxymethyl furfural (HMF) and lignin-derived pendant groups, generating a variety of aliphatic polyesters and potentially overcome current polymer challenges. Achieving a higher glass transition temperature (T_g) is one of …

Developing Injectable And Implantable Polymer Zwitterion Platforms For Glioblastoma Treatment, Sarah Ward

Doctoral Dissertations

This dissertation describes the synthesis, characterization, and application of novel polymer zwitterion-drug conjugates intended for treating glioblastoma, with a particular focus on phosphorylcholine (PC) and temozolomide (TMZ). Using versatile TMZ-containing monomers, injectable polymer prodrugs and implantable polymeric hydrogels were prepared over a broad range of drug incorporations with tunable properties, making them ideally suited for further in vivo and clinical evaluations. The work presented here greatly expands the knowledge base of TMZ formulations and gives rise to several routes which circumvent the challenges associated with its use. Chapter 2 describes the incorporation of a novel TMZ-methacrylate monomer into random and …

Synthesis Of Functional Chalcone Library For Use In Aza- Dipyrromethene Dye Systems, Kendal Crawley

Murray State Theses and Dissertations

Over the past decade, Aza-Bodipy dyes (ADPs), a derivative of the extensively studied BF₂-dipyrromethene (BODIPY), have become a growing field of research due to their unique photophysical properties, high yielding synthesis, and relative stability. They possess a unique spectral window of 600 to 750 nm which is the red to near-IR region, evidenced by the blue color of many of these dyes. Increasing interest in these dyes is due to this near-IR window which is important for many applications.^1-4 ADP chromophores also have a common core motif to that of phthalocyanines which allow for coordination at their …

Poly(Β-Gal-Thr): A New Scalable Synthetic Mucin, Manuel A. Lema

Dissertations and Theses

A method for the preparation of glycosylated polypeptides via the nucleophilic ring-opening polymerization of a glycosylated N-carboxyanhydride (NCA) monomer is reported. The synthesis of 2,3,4,6-tetraacetyl-β-galactose-threonine N-carboxyanhydride (β-AcO-Gal-Thr-NCA) monomer in 5 steps with an 8 % overall yield is described, and the single-crystal X-ray structure is provided. The effect of a series of Ni⁰-based organometallic initiators, nucleophilic amine initiators, co-catalysts, and solvents on the polymerization were explored. The kinetics of the three most promising conditions were studied in greater detail. The conditions that provided the highest yield, low polydispersity (Ð), and …

Single-Variable Porous Nanomaterial Series From Polymer Structure-Directing Agents, Morgan Stefik

Faculty Publications

Block polymer structure-directing agents (SDA) enable the production of porous nanoscale materials. Most strategies rely upon polymer equilibration where diverse morphologies are realized in porous functional materials. This review details how solvent selectivity determines the polymer SDA behaviors, spanning from bulk-type to solution-type. Equilibrating behavior of either type, however, obscures nanostructure cause-and-effect since the resulting sample series convolve multiple spatial variations. Solution-type SDA behaviors include both dynamic and persistent micelles. Persistent micelle templates (PMT) use high solvent selectivity for kinetic entrapment. PMTs enable independent wall thickness control with demonstrated 2 Å precision alterations. Unimodal PMT pore size distributions have spanned …

Controlling Degradation With Force And Light, Brad Davis

Dissertations

Stimuli-responsive polymers respond to changes in their environment by altering their physical and chemical properties. Their responsiveness allows them to be used as sensors, mechanical actuators, delivery systems, and can yield either elongated lifetimes through healing mechanisms or shortened lifetimes through triggered degradation. Still a growing field in polymer science, researchers seek to expand the capabilities of these materials by improving their specificity, range, and mechanisms of both the stimuli and the response. The work presented explores stimuli-responsive materials, focusing on mechanical and light stimuli, and how to gain control of the response by specific changes in the polymeric material. …

Behavioral Modulation Of Supramolecular Assemblies Via Covalent And Non-Covalent Interfacial Transformations, Ann Fernandez

Doctoral Dissertations

There are several molecular level mechanisms at the origin of biological functions that serve as inspiration for the development of the “next generation” of materials that display adaptive and interactive properties. However, it will take time for synthetic materials to approach the level of complexity, robustness, and adaptability of biological systems. Although there are switchable platforms that respond via sensitized molecular components, there are currently no examples of materials that truly possess the type of autonomous behavior seen in biological systems. Even though these concepts are common in living organisms, their translation into a synthetic platform remains challenging to this …

Synthesis, Self-Assembly, And Material Applications Of Unimolecular Polyviologens, Abigail Delawder

Arts & Sciences Electronic Theses and Dissertations

Intellectual Gaps: Synthesis of high molecular weight, unimolecular, and sequence-defined polyviologens; spatiotemporal control over mechanical properties of materials using visible and near-IR light; on-demand, post hoc manipulation of materials

Intellectual Merit: Robust method for synthesizing higher-order polyviologens of distinct molecular weight; control the change in the mechanical properties of polymer-based, crosslinked materials using a wide range of wavelengths of light; degradation of viologen-crosslinked hydrogels

To understand fundamentally how viologens behave within a polymer chain, we needed a better and more efficient way of synthesizing these long chains of polyviologens. As simple as this process looks on paper, the synthesis is …

Electrochemical Studies Of Poly 3-(4-Methoxyphenyl)[5] Ferrocenophane-1,5-Dimethylene And Copolymers With Styrene And N-Phenylmaleimide, Niyati Arora

Electronic Theses & Dissertations

Ferrocene is an organometallic compound in which an iron atom is sandwiched between two cyclopentadienyl rings. Ferrocene containing polymers receive a considerable amount of research because of their known chemistry, stable redox reactions and useful electrical systems. Noteworthy are their uses as electrode coatings, electro-catalysts and as an anode in battery applications. In this research, the synthesis and polymerization of a ferrocenophane diene is reported. Using a Wittig reaction 3-(4-methoxyphenyl)[5]ferrocenophane-1,5-dimethylene was synthesized from 3-(4-methoxyphenyl)[5]ferrocenophane-1,5-dione. The homopolymer and copolymers with styrene and N-phenylmaleimide were synthesized via free radical polymerization from 3-(4-methoxyphenyl)[5]ferrocenophane-1,5-dimethylene using AIBN as the initiator. These polymers were characterized using …

Conducting Materials As Building Blocks For Electronic Textiles, Anja Lund, Yunyun Wu, Benji Fenech-Salerno, Felice Torrisi, Tricia Breen Carmichael, Christian Müller

Chemistry and Biochemistry Publications

Abstract: To realize the full gamut of functions that are envisaged for electronic textiles (e-textiles) a range of semiconducting, conducting and electrochemically active materials are needed. This article will discuss how metals, conducting polymers, carbon nanotubes, and two-dimensional (2D) materials, including graphene and MXenes, can be used in concert to create e-textile materials, from fibers and yarns to patterned fabrics. Many of the most promising architectures utilize several classes of materials (e.g., elastic fibers composed of a conducting material and a stretchable polymer, or textile devices constructed with conducting polymers or 2D materials and metal electrodes). While an increasing number …

A Conductivity Analysis Of A Newly Synthesized Poly(Ethylene Glycol) Methyl Ether Hydroxide Electrolyte, Sarah Marie Peterson

Honors Theses

This thesis investigates the synthesis and conductive properties of a Poly (ethylene glycol) methyl ether-based polymer electrolyte. The goal of the synthesis is to enhance the hydroxide ion conduction properties of the polymer with its cationic groups attached. The MePEG backbone contained seven ethylene glycol groups and was modified to substitute the hydroxide group in the MePEG with trimethylamine. In addition, the bromide added in the synthesis was exchanged for hydroxide ions to allow for the transportation of hydroxide ions in polymeric electrolytes that can be used in Anion Exchange Membrane Fuel Cells. The newly synthesized polymer was compared to …

Stretching The Applications Of Biomass: Development Of Lignin Based Thermoplastic Elastomers And Composite Materials, Anthony Stephen Bova

Doctoral Dissertations

Bio-based plastics and composites have seen increased industry adoption in recent years due to growing demand for materials with a low carbon footprint. The use of lignin as a feedstock for polymers has seen growing interest as the concept of an integrated cellulosic biorefinery gains traction and advances the need to use all components of separated biomass for value-added applications. Historically, use of lignin in thermoplastic and elastomeric copolymers and blends has been bottlenecked by the inability to introduce lignin content above 30 weight percent due to difficulties with interfacial adhesion of lignin with other soft segments. Efforts to overcome …

Development Of Biomaterials For Drug Delivery, Raquel De Castro

Graduate Theses and Dissertations

Drug delivery systems (DDS) have highly evolved in the last decades with the development of hydrogels and nanoparticles. However, high systemic uptake, side effects, low bioavailability, and encapsulation efficiency continue to be a major hurdle faced by such DDSs.

Nanoparticles and hydrogels can be specifically designed for targeted DDSs to mitigate some of the problems. This dissertation aimed to design two DDSs for ocular drug delivery and one for cancer treatment. The first project sought to develop chitosan nanoparticles (Cs-NP) using PEGDA as a copolymer to encapsulate gentamicin (GtS) for ocular drug delivery. Cs-NPs contain positive charges that can interact …

Effect Of Precise Control Of Crosslink Density On The Thermal, Mechanical, And Conductive Properties Of Covalently Crosslinked Ionene Networks, Alexander Thome

Honors College Theses

Ionic liquids (ILs), besides being well known as environmentally friendly solvents, have attracted attention for a wide variety of other applications, including gas separation, 3D-printing and electrochemical actuators. However, for many such applications, incorporation of the IL moiety into a polymeric material eliminates the use of mechanically unstable free ILs while maintaining many of their electrochemical benefits. Such polymers can take two basic forms: poly(ionic liquid)s are ion-containing polymers in which the IL group is attached pendant to the polymeric backbone, while ionenes are ion-containing polymers in which the IL group is anchored directly into the backbone of the repeating …

Thermal, Mechanical, And Rehealing Properties Of Cross-Linked Ionene Networks, Katelyn Lindenmeyer

Honors College Theses

Polymers which contain ionic liquid groups have numerous applications in a wide variety of fields. Past research from our group has shown that IL-containing polymers which exist in covalently crosslinked networks can exhibit good ionic conductivities despite the hindrance in polymer chain mobility and relaxation. In part one of this thesis, efforts to create ionic networks which have the capability of being rehealed after exposure to an external stimulus are discussed. Thermoreversible maleimide-furan chemistry was incorporated into an imidazolium-containing ionene network. Maleimide-terminated, imidazolium-containing monomers were coupled with furan-functionalized monomers, prepared from commercially available multifunctional acrylates. Thermal, mechanical and rheological characterization …

Polymer Particles For The Intra-Articular Delivery Of Drugs To Treat Osteoarthritis, Xueli Mei, Ian J. Villamagna, Tony Nguyen, Frank Beier, C. Thomas Appleton, Elizabeth R. Gillies

Chemistry Publications

Osteoarthritis (OA) is a leading cause of chronic disability. It is a progressive disease, involving pathological changes to the entire joint, resulting in joint pain, stiffness, swelling, and loss of mobility. There is currently no disease-modifying pharmaceutical treatment for OA, and the treatments that do exist suffer from significant side effects. An increasing understanding of the molecular pathways involved in OA is leading to many potential drug targets. However, both current and new therapies can benefit from a targeted approach that delivers drugs selectively to joints at therapeutic concentrations, while limiting systemic exposure to the drugs. Delivery systems including hydrogels, …

Two-Electron Donating Phenothiazines And Use Thereof, Susan A. Odom, Aman Preet Kaur, Matthew D. Casselman, Nuwan Harsha Attanayake

Chemistry Faculty Patents

Compounds for use as electrolyte in a non-aqueous redox battery are provided, including an N-substituted phenothiazine compound according to the formula: (see patent for formula.)

R' is alkyl and R is selected from alkyl, aryl, alkylaryl, alkoxyaryl, alkylcarboxyl, arylcarbonyl, haloalkyl, perfluo- roalkyl, glycol, polyether, haloaryl, a negative electrolyte, a polymerizable unit, and a polymer.

An Investigation Of Cross-Links On Crystallization And Degradation In A Novel, Photocross-Linkable Poly (Lactic Acid) System, Nicholas Baksh

USF Tampa Graduate Theses and Dissertations

Polymeric molecular structure consists of repeating units bonded together. Mechanicalproperties can be altered without affecting chemical makeup by altering the number of these units. Small molecules can be introduced and/or polymers can be modified to form bonds between molecular chains. Cross-linking, as this is called, also introduces mechanical variation with minimal effects on chemical composition. Lastly, polymer chains reorient themselves in response to intermolecular forces. This temperature dependent response is known as crystallization. Although chemistry is unaltered, mechanical properties can depend highly on the percent of the sample that is crystallized.

Cross-linking is known to enhance the mechanical properties of …

Fabrication And Qualitative Analysis Of An Optical Fibre Efpi-Based Temperature Sensor, Fintan Mcguinness, Aidan Clooney, Mohamed Oubaha, Dinesh Babu Duraibabu, M. Mahmood Ali, Gerald Kilkelly, Emma Tobin, Gabriel Leen

Articles

The following presents a comparison of an extrinsic Fabry–Perot interferometer (EFPI)- based temperature sensor, constructed using a novel diaphragm manufacturing technique, with a reference all-glass EFPI temperature sensor. The novel diaphragm was manufactured using polyvinyl alcohol (PVA). The novel sensor fabrication involved fusing a single-mode fibre (SMF) to a length of fused quartz capillary, which has an inner diameter of 132 µm and a 220 µm outer diameter. The capillary was subsequently polished until the distal face of the capillary extended approximately 60 µm beyond that of the single mode fibre. Upon completion of polishing, the assembly is immersed in …

Polyesters With Main And Side Chain Phosphoesters As Structural Motives For Biocompatible Electrospun Fibres, André E. Polloni, Viviane Chiaradia, Ronaldo José F.C. Do Amaral, Cathal Kearney, Brian Gorey, Débora De Oliveira, José V. De Oliveira, Pedro H.H. De Araújo, Claudia Sayer, Andreas Heise

Articles

Phosphoester containing polymers are promising materials in biomedical applications due to their biocompatibility and biodegradability. Utilising thiol-ene chemistry, the synthesis of two novel structural polymer motives combining polyesters and phophoester groups was explored. The first polymer was obtained by coupling ene-functional poly(thioether-phosphoester) with thiol functional poly(pentadecalactone). While the coupling reaction was successful, yields remained low presumably due to inadequate endgroup stoichiometry. The second polymer comprised phosphoester side groups conjugated to unsaturated poly(globalide). Double bond conversions up to 84% were achieved depending of the type of phosphoester thiol and relative reactant ratios. The resulting polymers transitioned from solid semicrystaline to liquid …