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Full-Text Articles in Physical Sciences and Mathematics
Controlling Degradation With Force And Light, Brad Davis
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. …
Synthesis, Self-Assembly, And Material Applications Of Unimolecular Polyviologens, Abigail Delawder
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 …
Stretching The Applications Of Biomass: Development Of Lignin Based Thermoplastic Elastomers And Composite Materials, Anthony Stephen Bova
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
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 …
A Conductivity Analysis Of A Newly Synthesized Poly(Ethylene Glycol) Methyl Ether Hydroxide Electrolyte, Sarah Marie Peterson
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 …
Thermal, Mechanical, And Rehealing Properties Of Cross-Linked Ionene Networks, Katelyn Lindenmeyer
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 …
Effect Of Precise Control Of Crosslink Density On The Thermal, Mechanical, And Conductive Properties Of Covalently Crosslinked Ionene Networks, Alexander Thome
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 …
An Investigation Of Cross-Links On Crystallization And Degradation In A Novel, Photocross-Linkable Poly (Lactic Acid) System, Nicholas Baksh
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 …
Reversible Addition-Fragmentation Chain-Transfer Emulsion Polymerization And Its Application To Waterborne Coatings, Andrew Balgeman
Reversible Addition-Fragmentation Chain-Transfer Emulsion Polymerization And Its Application To Waterborne Coatings, Andrew Balgeman
Graduate Research Theses & Dissertations
Waterborne acrylic latex makes up a vast majority of the architectural coatings market, including most of the paints sold in retail stores. Most, if not all, of these latex formulations are prepared using radical polymerization of acrylic monomers. Reversible addition-fragmentation chain-transfer (RAFT) polymerization has been researched for over two decades, but to this point has made very little progress finding success in commercial applications. Indeed, a majority of RAFT research has been dedicated to successfully polymerizing different monomers with good degree of polymerization control, and very little research has been directed toward actual coating applications. In this study, we focused …
Multi-Level Analysis Of Atomic Layer Deposition Barrier Coatings On Additively Manufactured Plastics For High Vacuum Applications, Nupur Bihari
Dissertations, Master's Theses and Master's Reports
While hardware innovations in micro/nano electronics and photonics are heavily patented, the rise of the open-source movement has significantly shifted focus to the importance of obtaining low-cost, functional and easily modifiable research equipment. This thesis provides a foundation of open source development of equipment to aid in the micro/nano electronics and photonics fields.
First, the massive acceptance of the open source Arduino microcontroller has aided in the development of control systems with a wide variety of uses. Here it is used for the development of an open-source dual axis gimbal system. This system is used to characterize optoelectronic properties of …
Proto-Rna Synthesis Using Glycerol And Phosphate Anion, Noah Parker
Proto-Rna Synthesis Using Glycerol And Phosphate Anion, Noah Parker
Williams Honors College, Honors Research Projects
Nucleic acids are important molecules for all life, serving as the primary molecules for information storage and reproduction. RNA has long been thought to be the molecule that initiated protein synthesis. However, RNA has recently been thought to be too complex to synthesize prebiotically. Through a 1:1 mole ratio condensation of glycerol and phosphoric acid, I generated glycerol-phosphate oligomers that resemble a primitive form of the carbon-phosphate backbone of RNA. 75 mmol MgCl2 was added to some samples to see if the Mg cation could stabilize the reaction intermediates and further promote longer proto-RNA oligomers. These samples were all heated …
Advancements In Bio-Based Novel (Co)Monomers For Polymeric Materials, Khristal Anne Monroe
Advancements In Bio-Based Novel (Co)Monomers For Polymeric Materials, Khristal Anne Monroe
Electronic Theses and Dissertations
Most current research in the area of sustainable and environmentally friendly materials relate to the use of renewable sources for the fabrication of bio-based polymers and composites. Using plant-based derivatives is a common strategy. Pine sap can be distilled into turpentines (light fraction) and pine rosin (heavy fraction). Pine rosin is obtained as a brittle solid and its major component is abietic acid. This project aims at investigating a synthetic approach for the synthesis of a pine rosin-based polymer that can be potentially used for manufacturing a collection device for pine sap. The synthetic strategy consisted in the preparation of …
Design, Synthesis And Applications Of Nanoparticles In Suppression Of Mosquito-Born Flaviviridae Viruses, Maria R. Blahove
Design, Synthesis And Applications Of Nanoparticles In Suppression Of Mosquito-Born Flaviviridae Viruses, Maria R. Blahove
Electronic Theses and Dissertations
Recently, nanoparticles have become an origin of exploration in the chemistry field due to their unique medical uses. The current drug delivery models of nanoparticles often include a metal base with a drug conjugated to its surface. However this raises concerns regarding toxicity. A novel approach to solving this dilemma is the development of nanosized biocompatible polymer-based micelles, created from PEG-PCL-PEG triblock polymer, and formed around a drug of choice. The goal is to create a drug carrier nanoparticle system that is labile at a specific intracellular pH, without undue toxicity to the cell. This creates a drug-loaded nanoparticle that …