Chemistry Commons^™

Cyclodextrin-Based Supramolecular Drug-Delivery Nanomaterials And Shear-Thinning Hydrogels Using Ring-Opening Metathesis Polymerization, Ruihan Li

Arts & Sciences Electronic Theses and Dissertations

Cyclodextrins (CD) are a family of oligosaccharides that can non-covalently and precisely bind small hydrophobic drug molecules, such as antibiotics and anticancer drugs, through well-defined host-guest interactions inside the inner cavity of the macrocycle. Ring-opening metathesis polymerization (ROMP) is a versatile, functional group tolerant method of polymerization that is underexplored in biomedical applications relative to the more common controlled chain-growth polymerizations. In this dissertation, I describe my efforts to combine the supramolecular chemistry of CDs with that of ROMP using specialized functional monomers to synthesize several CD-based polymeric drug delivery nanomaterials. For example, in Chapter 2, a new type of …

Corn Oil-Based Highly Flame Retardant Rigid Polyurethane Foams For Industrial Application, Muhammad Rizwan Sulaiman

Electronic Theses & Dissertations

The synthesis of flame retardant polyurethane (PU) foam was carried out using two different flame retardants, such as triethyl phosphate (TEP) and triphenyl phosphate (TPP). The thermal and mechanical characteristics of the foam were analyzed. The obtained TGA results confirmed that the flame retardant acts in the gaseous form to stop the fire. All the prepared samples displayed excellent closed cell content, which was above 90 %. The burning time were reduced from 80 s to 7.5 s with the weight loss 3.2% of for sample E-12 (19.29 % TEP) and from 80 s to 11 s with the weight …

Application Of Single-Ion Conducting Polymer Electrolytes (Sicpes), Sheng Zhao

Doctoral Dissertations

Polymer electrolytes have been widely studied as a potential candidate for next generation batterie with improved safety and higher energy density. Especially, single-ion conducting polymer electrolytes (SICPEs) have attracted significant attention due to their almost unity lithium-ion transport number, which is believed to help suppress lithium dendrite growth and extend battery cycle life. However, there is still a long way to go before they can be practically applied in batteries, due to their relatively low ionic conductivity at ambient temperature. Therefore, the main goal of this work is to explore various methods that can improve the ionic conductivity of SICPEs …

Interfaces And Dynamics In Polymeric 3d Printing And Crystalline Polymer Blends, Stevenson C. Perryman

Doctoral Dissertations

This dissertation presents experimental work that provide a foundation to rationally improve fused filament fabrication (FFF) and immiscible blend compatibilization. Objects generated from additive manufacturing processes, such as FFF, have intrinsic structural weaknesses which include two project specific examples: structural anisotropy and irreversible thermal strain. Due to low adhesion between individual print layers that results in macroscopic defects, the mechanical strength of printed objects when force is applied perpendicular to the build orientation is drastically reduced. In the first dissertation chapter, we present a protocol to produce interlayer covalent bonds by depositing multi-amine additives between individual layers of a print …

Synthesis Of Polyethylene Glycol-Based Hydrogels And Silver/Gold Nanostructures For Biomedical Applications, Isabelle Ishimwe Niyonshuti

Graduate Theses and Dissertations

This work focuses on the synthesis of biocompatible polyethylene glycol (PEG)-based hydrogels, silver nanoparticles (AgNPs), and silver-gold nanocages (Ag-AuNCs) for biomedical applications. The dissertation includes two parts with Part I on the work of PEG-based hydrogel for wound healing applications and Part II on the work of Ag/Au nanostructures for antimicrobial applications. Part I studies PEG-based hydrogel for the delivery of fibroblast growth factors (FGFs) for wound healing applications, aiming to overcome the challenge of designing hydrogels capable of the sustained release of bioactive FGFs. This research develops new biocompatible anionic injectable hydrogel formulations based on Poly (Oligo Ethylene Glycol …

Functional Material Systems For Stimuli-Responsive Interference Coloration, Milad Momtaz

Theses and Dissertations

Part I: Responsive Interference Coloration (RIC) Systems for High-Performance Humidity Sensing

High-humidity conditions (85−100% relative humidity) have a variety of effects on many aspects of our daily lives. In spite of significant progress in the development of structural coloration-based humidity sensors, enhancing the sensitivity and visual humidity resolution of these sensors at high-humidity environment remains a big challenge. In this work, high-performance colorimetric humidity sensors based on environment-friendly konjac glucomannan (KGM) are introduced. These sensors are fabricated via thin-film interference and prepared using a simple, affordable, and scalable method. An effective approach is shown for markedly improving the sensitivity and …

Synthesis, Characterization, And Direct-Ink-Writing Of Syntactic Foams, Andrea Irigoyen

Open Access Theses & Dissertations

This project encompasses three different methods to fabricate syntactic foams using a PDMS matrix i.e., hollow spheres inclusion, pore generator leaching by solvent, and emulsion. The foam formation by using polysiloxane hollow spheres is done in a 3-step process. The first step is to create a core of polystyrene following a dispersion polymerization process. The goal for the size of the pore is to monodisperse and have an average diameter of 5-10 μm, so the polystyrene core must be as well within that range. After that, the cores are coated with a polysiloxane shell by following a polymerization by condensation …

Designing Polymer Materials For Improved Additive Manufacturing, Kaizhong Guan

Masters Theses

Currently, two of the most used additive manufacturing methods for polymers are selective laser sintering (SLS) and fused filament fabrication (FFF). Although at high market size, they both have imperfections. The materials for SLS are limited and the objects manufactured by FFF existing anisotropic behavior. Targeting on these drawbacks, this thesis has proposed a novel method to prepare polypropylene (PP) microsphere which is suitable for SLS with low cost and scalable potential; and a novel material with polycarbonate as matrix that has shown a decrease in anisotropy after FFF printing.

The PP microsphere in this thesis was prepared via liquid-liquid …

Fast & Efficient Simulation For Long Polymeric Chains, Naeyma N. Islam

University of New Orleans Theses and Dissertations

No abstract provided.

Synthesis And Characterization Of Pyridine-Based Diimide Ligands And Metal Phosphonate Coordination Polymers, Juan Pinedo

Honors Program Theses and Research Projects

Coordination polymers have been a topic of interest because of the large variety of applications these materials have. in particular Metal-Organic Frameworks (MOFs) have been researched due to their porosity and simple synthetic pathways. Structurally a MOF is composed of one or more organic ligands serving as the backbone of the structure. These ligands are complexed with metal ions coordinating into the desired structure. It is this structure that gives way to a variable porosity useful for proton conductivity and material transport. By varying backbone size a framework can be customized for use in specific conditions. This is due not …

The Synthesis And Application Of Polyglyoxylamides, Quinton Ea Sirianni

Electronic Thesis and Dissertation Repository

Self-immolative polymers (SIPs) are a subset of degradable polymers that can be triggered to fully depolymerize with a single stimulus event. This amplifying behaviour makes them ideal for real-world applications including sensors, recyclable plastics, and drug delivery vehicles. Polyglyoxylates (PGs) are a class of SIPs that can be synthesized in a one-pot reaction and designed to respond to different stimuli including light, heat, reduction, and oxidation. However, with the exception of poly(ethyl glyoxylate) (PEtG), the various glyoxylate monomers must be prepared and purified before polymerization, which can be difficult. Furthermore, PGs typically possess properties such as water-insolubility and low glass …

Advanced Materials Design Using Application-Based Processing Techniques, Daniel S. Camarda

Doctoral Dissertations

This dissertation pertains to generating advanced materials using application-based processing techniques. First, billets consisting of PTFE sintering powders are evaluated using Thermomechancal Analysis. It was found that both shape change and volume change are associated with enthalpic and entropic recoil, respectively. These phenomena, due to melting and stored energy during the powder compaction process, were found to be molecular weight dependent. Additionally, kinetics of the recovery and sintering process were found to be slower in blended specimens than pure samples. Next, the creation of graft copolymers by selectively grafting a second polymer to the amorphous fraction of a semi-crystalline polymer …

Chitosan Graphene Composite Fabrication And Characterization For Treatment Of Harmful Algal Blooms And Toxins, Sarah Zetterholm

Master's Theses

Chitosan graphene composites were fabricated and characterized as a management strategy for harmful algal blooms (HABs) caused by various species of cyanobacteria. These chitosan graphene materials were compared to previously studied chitosan graphene-oxide composites in both material properties and HAB treatment. In previous studies, adsorption of the cyanobacteria onto the surface of the composite materials has been observed. Investigations of the pure materials for these composites are also included in this study to determine whether removal is a result of charge interactions with the composite, or as an inherent property of the graphene or graphene oxide. Initial results suggest that …

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. …

Emergence Of Non-Hexagonal Crystal Packing Of Deswollen And Deformed Ultra-Soft Microgels Under Osmotic Pressure Control, Molla R. Islam, Rachel Nguyen, L. Andrew Lyon

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Highly solvent swollen poly(N-isopropylacrylamide-co-acrylic acid) microgels are synthesized without exogenous crosslinker, making them extremely soft and deformable. These ultralow crosslinked microgels (ULC) are incubated under controlled osmotic pressure to provide a slow (and presumably thermodynamically controlled) approach to higher packing densities. It is found that ULC microgels show stable colloidal packing over a very wide range of osmotic pressures and thus packing densities. Surprising observation of co-existence between hexagonal and square lattices is also made over the lower range of studied osmotic pressures, with microgels apparently changing shape from spheres to cubes in defects or grain boundaries. It is proposed …

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 …

Tools And Strategies For The Patterning Of Bioactive Molecules And Macromolecules, Daniel J. Valles

Dissertations, Theses, and Capstone Projects

Hypersurface Photolithography (HP) is a printing method for fabricating structures and patterns composed of soft materials bound to solid surfaces and with ~1 micrometer resolution in the x, y, and z dimensions. This platform leverages benign, low intensity light to perform photochemical surface reactions with spatial and temporal control of irradiation, and, as a result, is particularly useful for patterning delicate organic and biological material. In particular, surface- initiated controlled radical polymerizations can be leveraged to create arbitrary polymer and block- copolymer brush patterns. Chapter 1 will review the advances in instrumentation architectures from our group that have made these …

Enhanced Platinum (Ii) Drug Delivery For Anti-Cancer Therapy, Marek T. Wlodarczyk

Dissertations, Theses, and Capstone Projects

Over the years, anti-cancer therapies have improved the overall survival rate of patients. Nevertheless, the traditional free drug therapies still suffer from side effects and systemic toxicity, resulting in low drug dosages in the clinic. This often leads to suboptimal drug concentrations reaching cancer cells, contributing to treatment failure and drug resistance. Among available anti-cancer therapies, metallodrugs are of great interest. Platinum (II)-based agents are highly potent and are used to treat many cancers, including ovarian cancer (OC). Cisplatin (cis-diaminedichloroplatinum (II)) is the first Food and Drug Administration (FDA)-approved metallodrug for treatment of solid tumors, and its mechanism …

Design Of Resposive Oligomeric And Polymeric Interfaces For Sensing And Controlled Release Applications, . Manisha

Doctoral Dissertations

Nature has designed magnificent responsive systems by constructing several interacting molecular level networks for the recognition and propagation of chemical and biochemical information. One of the eminent characteristics of these systems is their capability to quickly transduce molecular scale recognition events into macroscopic or visually observable responses. Inspired by these systems present in nature, we became interested in developing artificial responsive systems with similar capabilities. This dissertation will feature four such systems that employ amphiphilic oligomers and polymers which were chosen as the scaffolds because of their high thermodynamic stability, low critical aggregation concentrations, convenient handles to incorporate functional group …

Immobilized-Enzyme Reactors Integrated Into Analytical Platforms: Recent Advances And Challenges, Bert Wouters Dr, Sinead Currivan, Noor Abdulhussain, T. Hankemeier, Peter J. Schoenmakers

Articles

Immobilized-enzyme reactors (IMERs) are flow-through devices containing enzymes that are physically confined or localized with retention of their catalytic activities. IMERs can be used repeatedly and continuously and have been applied for (bio)polymer degradation, proteomics, biomarker discovery, inhibitor screening, and detection. Online integration of IMERs with analytical instrumentation, such as high-performance liquid chromatography (HPLC) systems, reduces the time needed for multi-step workflows, reduces the need for sample handling, and enables automation. However, online integration can also be challenging, as reaching its full potential requires complex instrumental setups and experienced users. This review aims to provide an assessment of recent advances …

Development Of Catalysts For The Ring-Opening Polymerization Of Cyclic Esters And The Coordination-Insertion Polymerization Of Olefins, Alicia Doerr

Doctoral Dissertations

Over the past few decades, interest in the design and synthesis of tailorable polymeric materials has grown due to the well documented correlation between structure, property, and function. However, in order to obtain polymers with desired microstructures, well controlled synthetic methods are needed. Therefore, the continued investigation of homogeneous, single-site polymerization catalysts is important to gain a deeper understanding of how systematic modifications of polymerization conditions, ligand scaffold, metal center identity, cocatalyst or activator identity, etc. affect the catalytic activity, selectivity, and/or polymer topology obtained when using these catalysts for the polymerization of a variety of monomers. This dissertation will …

Characterization Techniques And Cation Exchange Membrane For Non-Aqueous Redox Flow Battery, Kun Lou

Doctoral Dissertations

The motivation of this work comes from one of the major problems of emerging non-aqueous flow battery (NAFB) that a separator or membrane which facilitates conductivity and blocks redox species crossover does not exist. Although many aspects of principles can be mirrored from mature fuel cell and aqueous flow battery, it is found that some well-defined membrane properties in aqueous systems such as swelling, transport and interactions are different in non-aqueous solvents to some extent. However, the approach of this work does follow the way perfluorosulfonate ion exchange membrane (PFSA) facilitated development of fuel cell and aqueous flow battery in …

Stimuli-Responsive Polyelectrolytes: Thermosensitive Zwitterionic Polymers And Charged Shape-Changing Star Molecular Bottlebrushes, Evan M. Lewoczko

Doctoral Dissertations

This dissertation work investigated two classes of stimuli-responsive polyelectrolytes: thermosensitive zwitterionic poly(sulfobetaine methacrylate)s (PSBMAs) and charged shape-changing star molecular bottlebrushes (SMBs). While zwitterionic polymers are explored for numerous applications, their structure-solution behavior relationship was poorly understood. The first part of this dissertation focused on the effects of N-substituents of PSBMAs on their behavior in water. A series of PSBMAs were synthesized, with systematically changed N-substituents, including symmetric N-n-alkyl substituents of various lengths and asymmetric N-substituents comprising one methyl and either one cyclohexyl, phenyl or 2-hydroxyethyl group. The behavior of PSBMAs with symmetric N-substituents …

Synthesis Of The Diazonium Zwitterionic Polymer/Monomer For Use As The Electrolyte In Polymer Electrolyte Membrane (Pem) Fuel Cells, Josiah Marshall

Electronic Theses and Dissertations

My research goals are to synthesize new zwitterionic perfluorosulfonimide (PFSI) monomer/polymers. They are expected to replace traditionally used perfluorosulfonic acid (PFSA) polymers as the electrolyte in PEM fuel cells. For the PFSI monomer preparation, we designed a nine-step synthesis route. Thus far, I have successfully completed the synthesis of 4- (2-bromotetrafluoroethoxy)-benzenesulfonyl amide, 4-acetoxybenzenesulfonic acid sodium salt, and 4-chlorosulfonyl phenyl acetate. The coupling reaction of 4-(2-bromotetrafluoroethoxy)- benzenesulfonyl amide with 4-chlorosulfonyl phenyl acetate, was troublesome due to slow reaction kinetics and byproducts. Additionally, I did a methodology study for the homopolymerziation of the perfluoro 3(oxapent-4-ene) sulfonyl fluoride monomer. We compared the weight …

Stimuli Responsive Dye-Containing Peg-Pla Block Copolymer Micelles And Computationally Assisted Design Of A Stapled Peptide Bundle, Tyler L. Odom

MSU Graduate Theses

In this thesis, I report the preparation and characterization of dye-containing PEG-b-PLA block copolymer micelles and the computational design of a novel coiled-coil peptide bundle. The PEG-b-PLA micelles encapsulate hydrophobic molecules into their core and have strong potential as nanocontainers or delivery vesicles. In theory, these internalized molecules can be released upon exposure to mechanical forces that disrupt the micellar structures. This force-responsive nature is one of the inherent properties of micellar systems. However, there is a stark lack of research that utilize this property in applications. Along those lines, I have studied the behavior of …

Doping Of Conjugated Polymers: Preparation, Characterization And Device Fabrication, Kan Tang

Dissertations

Semiconducting conjugated polymers (CPs) as emerging materials for advanced electronic applications such as sensors, OPVs, and OEFTs has become an intriguing research topic in the past decades. It opens a new avenue of “flexible” electronics, which has shown great potential in next-generation electronic devices.

However, due to the nature of CP materials and related solution processing techniques, unlike almost perfectly crystalline silicon materials, CPs in the solid-state often exhibit much lower crystallinity if it is not complete amorphous, which severely hinder the electronic property and optical property of the materials. The crystallinity of CPs in a film is often uniquely …

Photopolymer Networks With Tunable Command Destruct Properties, William Walker

Dissertations

Photoinduced thiol-catalyzed hydrogen abstraction and beta-scission of acyclic benzylidene acetals is demonstrated as a new route to “command-destruct” polymer thermosets. Using this approach, we show that poly(thioether acetal) networks synthesized via thiol-ene photopolymerization rapidly degrade to alkyl benzoate byproducts when triggered with light, transitioning from solid to liquid within seconds. The light-driven construction and destruction processes, accessible via distinct differences in kinetics, are readily amendable for photopatterning, additive/subtractive manufacturing, and wavelength-selective applications.

The first chapter of this dissertation details the development of command-destruct poly(thioether acetal) networks via a previously unexplored mechanism for polymer degradation. The degradation mechanism is confirmed via …

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 …

Degumming Of Hemp Fibers Using Combined Microwave Energy And Deep Eutectic Solvent, Bulbul Ahmed

LSU Master's Theses

Hemp is considered as one of the sustainable agricultural fiber materials. Degumming or surface modification of hemp bast is needed to produce single fibers for ensuing textile and industrial applications. The traditional degumming process necessitates a high amount of alkali, which causes detrimental environmental pollution. This study offers a new method to degum hemp fibers with reduced use of harmful alkali and precious water resources. In this work, hemp bast fibers were degummed by using combined microwave energy and deep eutectic solvent (DES). The properties of hemp fibers manufactured by this method were investigated and compared with the traditional alkali …

Preparation And Characterization Of Single Layer Conducting Polymer Electrochromic And Touchchromic Devices, Sharan Kumar Indrakar

USF Tampa Graduate Theses and Dissertations

Electrochromic devices (ECDs) have triggered great interest because of their potential applicability in energy-efficient buildings and low power display systems, including reflective type smart windows/mirrors and wearable-flexible devices. In the past decades, electrochromic technologies with different device structures and materials have been proposed. The idea of employing a simple device structure with a durable, cost effective electrolyte is crucial to designing and manufacturing high-performance ECDs. With this idea in mind, this thesis describes the various efforts to develop a simple ECD comprising of a composite single active layer gel electrolyte, sandwiched between two transparent conducting electrodes, lasting over 10,000 cycles …