Doctor of Philosophy, Miami University, 2024, Chemistry and Biochemistry

Reversible addition fragmentation chain transfer (RAFT) polymerization technique has revolutionized the field of polymer synthesis and chemistry. It has enabled coherent design of novel polymeric structures with enhanced properties for customized applications. Furthermore, access to precisely engineered macromolecules through mild reaction conditions, functional group and high impurity tolerance indicates the industrial importance of RAFT. Subsequently, it has a broad range of applications, from advanced coatings and adhesives, drug delivery systems, biomedical materials, smart and responsive polymers, nanotechnology and advanced materials amongst others. This dissertation presents a polymerization approach of the synergy of the intrinsic photochemistry of vinyl ketone monomers and polymerization control through RAFT polymerization technique in the synthesis of complex polymer architectures. In addition, RAFT polymerization technique is mediated by radicals in polymerization steps via processes that are controlled by polymerization kinetics. Enhanced efficiency in polymerization process is birthed from better understanding of the kinetics . The need for efficiency in this technique requires a cut close investigation into the underlying mechanisms and their corresponding impact on the kinetics. This dissertation also includes a study on exploiting the polymerization rate retardation in RAFT polymerization of a range of commonly polymerized vinyl monomers (this included both MAMs and LAMs) and harnessing the differing retarding strength of the monomers as a tool for a possible reclassification of monomers. Monomers of similar class were observed to exhibit differing retarding character, thus making their distinct retarding characters as a potential monomer classification tool. Also, temperature effect on conventional radical and RAFT photopolymerization are explored. This work highlights the potential benefits of using temperature in conjunction with photoch (open full item for complete abstract)

Committee: Dominik Konkolewicz (Advisor) Subjects: Chemistry; Organic Chemistry

Doctor of Philosophy, Case Western Reserve University, 2023, Macromolecular Science and Engineering

Due to the effort in the past two decades, reversible addition-fragmentation chain transfer (RAFT) polymerization has developed into one of the most versatile and powerful living radical polymerization (LRP) for preparing polymers with different architectures. However, challenge remains because the presence of oxygen will quench the initiation and propagation radicals. In recent years, photoinduced electron/energy transfer-RAFT (PET-RAFT) polymerization has been developed. This technique uses visible light to initiate the reaction and is compatible with ambient condition and green solvents. It also maintains the ability of producing well-defined polymers and possess high potential as an alternative of conventional RAFT technique. Chapter 1 reviewed basics of Raft polymerization and recent efforts in developing PET-RAFT polymerization. In addition, applications of PET-RAFT in flow chemistry and on polymer brushes are also discussed. Chapter 2 reported synthesis of a series of hyperbranched polymers via PET-RAFT self-condensing vinyl polymerization (SCVP) in a flow reactor, which showed considerable controllability in molecular weight and branching density by adjusting the feeding ratio of monomer to transmer. The synthesis of block copolymers was also discussed. Chapter 3 demonstrated a new approach for preparing polymer brushes on conductive surface via surface-initiated PET-RAFT polymerization (SI-PET-RAFT), which showed capability of encapsulating gold nanoparticles. In chapter 4, four different architectures of linear or branched polymers were fabricated on conductive surface using SI-PET-RAFT. Their difference in morphology and encapsulation ability was also discussed. Finally in chapter 5, conclusion, perspectives, and future work based on chapter 2-4 is represented.

Committee: Rigoberto Advincula (Advisor); Gary Wnek (Committee Chair); Fu-sen Liang (Committee Member); Mike Hore (Committee Member); Valentin Rodionov (Committee Member) Subjects: Polymer Chemistry; Polymers

Doctor of Philosophy, Miami University, 2022, Chemistry and Biochemistry

Polymers are everywhere and they are made up of a series of repeating units chained together. With increased demand for polymers with tailored applications, methods such as atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) were created in order to gain control of the growing chains. These methods provide a way to synthesize chains with known molecular weights and low dispersity. This work was designed to explore polymerization methods at its core. The analysis of the reaction rates is based on retardation, reaction conditions, and chain transfer reagent composition in order to help better understand the RAFT reaction mechanism. Looking at quintessential RAFT, many assumptions have been made about every aspect of the reaction; from choosing a chain transfer reagent all the way to the solvent choice. Many of these preconceived notions have not been thoroughly tested in parallel to each other. Here, we analyzed reaction rate along with chain length and dispersity to see how the growing polymers responded to variations from the literature standard. Rate retardation is the decrease in reaction rate as the concentration of chain transfer reagent increases. In our study, we analyzed beyond traditional dithiobenzoate chain transfer reagents in order to understand the universality of rate retardation within RAFT. RAFT also allows for complex architecture with unique physical properties, such as star polymers, blocks, and gradients. Within this dissertation, these complex architectures are studied by looking at the unique physical properties as well as the kinetics and composition of the polymer. This was important when analyzing the folding of the ortho-phenylene core of a star polymer and understanding how R group affects the control of synthesizing gradient polymers by RAFT.

Committee: Dominik Konkolewicz (Advisor); C. Scott Hartley (Advisor); Suzanne Harper (Committee Member); Richard Page (Committee Member); David Tierney (Committee Chair) Subjects: Chemistry

Master of Science in Polymer Engineering, University of Akron, 2021, Polymer Engineering

Many basic properties of polymer such as viscoelasticity, rubber elasticity and solidification temperatures are derived from the long, chain like nature of the molecules. At the same time the detailed chemical structure is used to fine tune the properties, such as the solubility and transition temperature. More varied properties are obtained by copolymerization of chemically distinct monomers. In this thesis, we report our studies on quaternized copolymers synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Two types of polymers are prepared by either first quaternizing one monomer, vinyl benzyl chloride, and copolymerizing with styrene or copolymerizing vinyl benzyl chloride and styrene and then quaternizing the polymer. The synthesized polymers were characterized by NMR, thermogravimetric analysis and differential scanning calorimetry to determine the differences in the microstructure and resultant material properties of the polymers synthesized by pre- and post-polymerization quaternization of the vinyl benzyl chloride groups in the polymer.

Committee: Kevin Cavicchi (Advisor); Weinan Xu (Committee Chair); Mark D. Soucek (Committee Member) Subjects: Materials Science; Polymer Chemistry; Polymers

Doctor of Philosophy, Miami University, 2021, Chemistry and Biochemistry

This work is designed to understand how to efficiently synthesize polymers for and to understand two major biotechnology applications - protein-polymer conjugates, and macromolecular surfactants for favorable cell membrane interactions. Polymers are a ubiquitous class of molecules in the world due to the unique and complex properties that arise from combining simple building blocks in particular combinations. Nature has adopted proteins, amino acid polymers that fulfill myriad critical functions. In recent years, the biotechnology industry has begun to manipulate proteins by attaching synthetic polymers to them, conferring invisibility to the immune system for protein drugs, or enhanced stability, activity, or recyclability to enzymes for biocatalysis. A protein molecule on its own is sufficiently complex to require years-long research projects to fully understand. Thus, protein-polymer conjugates are still poorly understood. In this work, we present a technique for the study of conjugates, enabled by reversible deactivation radical polymerization, which by nuclear magnetic resonance allows for an atomic-level view. We also explored the challenge of attaching two distinct polymers to a single protein molecule in an efficient and well-defined manner, which would enable still more complex conjugates. Lipid membranes and the proteins that reside within them are another area of biotechnology that polymers have broken into. Cell membranes and the proteins within them experience a complex play of intermolecular forces. The unique location of membrane proteins makes them difficult to study, as they are not readily crystallized, and resuspension using traditional detergents can be detrimental to protein structure. Styrene-maleic acid copolymers and their relatives are known to form a belt containing lipids and membrane proteins in disk-shaped nanoparticles. These maintain the bilayer shape and avoid the use of detergents and have enabled characterization of previously (open full item for complete abstract)

Committee: Dominik Konkolewicz PhD (Advisor); Richard Page PhD (Advisor); Richard Taylor PhD (Committee Chair); Carole Dabney-Smith PhD (Committee Member); Jason Berberich PhD (Committee Member) Subjects: Biochemistry; Biophysics; Chemistry; Polymer Chemistry; Polymers

Doctor of Philosophy, Miami University, 2020, Chemistry and Biochemistry

This work was designed to explore the photo-initiated polymerization techniques iniferter RAFT polymerization and photo-initiated thiol-alkene/alkyne coupling in order to both to gain a better insight into their mechanisms of action and to optimize their reaction conditions. Photo-initiated RAFT polymerization is a technique of interest due to the combination of control over polymerization that RAFT processes afford with the mild reaction conditions and spatial and temporal control of photochemical processes. Iniferter RAFT polymerization is an interesting subclass of photo-initiated-RAFT that eliminates the need for an added photo-catalyst, as the RAFT agent is directly excited by the photon source. To better understand the mechanism of the iniferter process, we set out to systematically study the iniferter RAFT mechanism through a Hammett type study by varying substituents on the dithiobenzoate moiety of the iniferter. Donating groups were found to accelerate the iniferter process, while withdrawing groups retard the reaction. This suggests a partial positive charge is being built up in the transition state towards bond homolysis, suggesting a formal oxidation of the thiocarbonylthio group. The unique efficiency of 2-cyano-2-propyl 4-methoxydithiobenzoate (CPMODB) as an iniferter was uncovered, as this polymerization was found to progress at a drastically enhanced rate, even when compared to phohotocatlyzed RAFT. In a separate study, the kinetics of iniferter RAFT polymerization in the presence of a tertiary amine was explored. This study investigated the effects of light source, CTA concentration, and amine concentration in order to understand the kinetic contribution of each. Data suggests an electron transfer from the amine to the excited RAFT end-group. Thiol reactions have gained attention in many areas of chemical research due to the "click" chemistry characteristics of these processes. A novel method of photochemical thiol-alkyne and thiol-alkene rea (open full item for complete abstract)

Committee: Dominik Konkolewicz (Advisor); Christopher Hartley (Committee Chair); Ben Gung (Committee Member); Neil Danielson (Committee Member); Burcin Bayram (Committee Member) Subjects: Chemistry; Organic Chemistry; Polymer Chemistry

Doctor of Philosophy, University of Akron, 2019, Polymer Science

Single chain nanoparticles (SCNPs) have recently achieved great success because of their significant potential in applications such as separation science and drug delivery. A major aim of these studies was to establish the factors that control their size. However, the effect of the spacer length between the polymer backbone and the cross-linkable site is not well established. This study presents the preparation of two series of linear polymers and their SCNPs with two different spacer lengths (3- and 11-carbons) in order to investigate the effect of the spacer on various properties of the nanoparticles. Sol-gel chemistry was used to crosslink single chains under conditions that prefer intramolecular cross-linking. The first series was poly[methyl methacrylate-co-3-(triisopropoxysilyl)propyl methacrylate]. Nanoparticles were prepared from copolymers containing 9 mol% silane monomer and with different molecular weights. Nanoparticles were also prepared from copolymers containing 22 and 31 mol% silane monomer. The second copolymer series was poly[methyl methacrylate-co-11-(triisopropoxysilyl)undecyl methacrylate]. The corresponding hyperbranched polymers were being prepared to determine the effect of polymer architecture on the preparation and properties of SCNPs. For this comparison. The silane-containing inimer, [2-bromo-2-(3'-triisopropoxysilyl)propan-1-oxycarbonyl]ethyl methacrylate was synthesized by hydrosilation of the allyl inimer, [2-bromo-2-(allyl-1-oxycarbonyl]ethyl methacrylate. The hyperbranched precursor polymers were prepared via atom transfer radical polymerization of the silyl inimer. Nanoparticles were produced by hydrolysis and condensation of the triisopropoxysilyl groups under pseudo-high dilution conditions to guarantee intramolecular crosslinking. To investigate the nanoparticle applicability as a stationary phase in chromatography, inverse gas chromatography (IGC) was used to thermodynamically characterize the prepared polymers and nanopart (open full item for complete abstract)

Committee: Coleen Pugh Ph. D. (Advisor); Yu Zhu Ph. D. (Committee Chair); Mesfin Tsige Ph. D. (Committee Member); Chrys Wesdemiotis Ph. D. (Committee Member); Sadhan Jana Ph. D. (Committee Member) Subjects: Analytical Chemistry; Chemistry; Materials Science; Organic Chemistry; Physical Chemistry; Polymer Chemistry; Polymers

Master of Science, Miami University, 2019, Chemistry and Biochemistry

Polymers are a versatile and tremendously important class of materials used in our everyday lives. They can be found in products including coatings in the aerospace industry, rubber tires in the automotive industry, and emulsifiers in the personal care industry. It is important to be meeting the demands for novel and superior materials and to be able to control how these materials are made on a molecular level. It is also essential to study their performance under various conditions. One method of controlling how a polymer is made is through a synthesis called Reversible Addition Fragmentation Chain Transfer (RAFT) polymerization. RAFT is widely used for its ability to create complex and predictable molecular architectures due to its superior tolerance to monomers. While RAFT polymers alone possess limited mechanical strength, adding dynamic covalent crosslinkers through Diels-Alder adducts can introduce properties like strength and self-healing. Carbon Nanotubes (CNTs) have been found to have both attractive conductive and mechanical properties. CNTs are a tube-shaped network of carbon atoms in a single or multi-walled arrangement. We propose that by adding multi-walled CNTs (MWCNTs) to a dynamic covalent RAFT polymer matrix, that it will reinforce properties such as strength, toughness, and introduce electrical conductivity.

Committee: Dominik Konkolewicz (Committee Chair); Scott Hartley (Committee Member); Mehdi Zanjani (Committee Member); Sparks Jessica (Committee Member) Subjects: Chemistry; Materials Science; Polymer Chemistry; Polymers

Doctor of Philosophy, Miami University, 2019, Chemistry and Biochemistry

Using dynamic chemistry to develop functional polymers is an emerging area in material science. This class of polymers possesses intrinsic reversibility owing to the covalent or noncovalent bonds within, therefore respond to external stimuli. In addition, combining dynamic interactions with polymers offers exciting dynamic features such as environmental adaptivity, malleability, self-healing, and shape memorizing properties. Noncovalent interactions, e.g., hydrogen bonds, metal-ligand coordination, host-guest interactions, ionomers or π-stacking, have been successfully built into polymers over the last decades. Researchers have also relied on dynamic covalent bonds, e.g., Diels-Alder adducts, disulfide exchange, imine bonds, or boronic ester bonds. However, the underlying kinetics of some covalent interactions have not been demonstrated explicitly. Besides, the dynamic nature of the crosslinkers introduces the potential for the material not only the weak toughness but also to creep or deform over time under load. Recently, a combination of dynamic and static crosslinkers on either the main polymer chains or side chains with different structures has been used to overcome these limitations and enhance the mechanical properties. Other than that, materials containing orthogonal dynamic chemistries enable the synthesis of intricate macromolecules which can respond to multiple stimuli to achieve the desired response. Our work mainly focuses on a deep understanding of the mechanism of the covalent interactions in terms of small molecule models to better manipulate them in the bulk polymers, making new dynamic materials, and exploring the impact of the macromolecular architectures on their properties. A mechanistic study of the thermally activated dynamic covalent chemistry of thiol-Michael adducts is the focus of Chapter two, using a model system of thiophenol/mercaptoethanol dynamic equilibrium with phenylvinylketone based Michael acceptors. Chapter three works on f (open full item for complete abstract)

Committee: Dominik Konkolewicz (Advisor); Scott Hartley (Committee Chair); Richard Taylor (Committee Member); Gary Lorigan (Committee Member); Jessica Sparks (Committee Member) Subjects: Chemistry; Materials Science; Organic Chemistry; Physical Chemistry; Polymer Chemistry; Polymers

Doctor of Philosophy, Miami University, 2018, Chemistry and Biochemistry

Polymers are a large part of daily life. As such, efficient ways to synthesize them are important. Techniques such as reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer radical polymerization (ATRP) allow for the controlled growth of polymers through radical polymerization. Photochemistry gives access to high energy intermediates and both spatial and temporal control. Photochemistry has been applied to both RAFT and ATRP with great success. A specific subset of photoRAFT polymerization, Photoinduced electron/energy transfer (PET)-RAFT has received great attention in recent years. Understanding the factors that affect the rate of the polymerization to allow for statistical comparisons between different research groups is important. It was discovered that although reactor geometry, volume, and concentration have little effect upon the kinetics, chain transfer agent and photocatalyst concentration and photoreactor intensity greatly impact the rate. With polymers being consumed in high quantities, new ways to allow for easy degradation of polymeric materials is important to allow them to be removed from the environment. Poly(phenyl vinyl ketone) (poly(PVK)) is a known photodegradable polymer under ultraviolet (UV) irradiation. Due to phenyl vinyl ketone's acetophenone subgroup, it can act as photoinitiator. Polymers of varying chain lengths were synthesized under self-initiated conditions under blue light irradiation and then degraded under UV irradiation. Although the PVK monomer absorbs significantly in the UV region and insignificantly in the blue region, irradiation with blue light is more efficient for polymerization. This phenomena led to a systematic study of self-initiated and photoredox initiated PET-RAFT polymerization of PVK under various wavelengths of light. This study showed that under self-initiated conditions, blue light was the most efficient energy source for promoting polymerization. Under photoredox PET-RAFT c (open full item for complete abstract)

Committee: Dominik Konkolewicz PhD (Advisor); Richard Taylor PhD (Committee Chair); C. Scott Hartley PhD (Committee Member); Richard Page PhD (Committee Member); Natosha Finley PhD (Committee Member) Subjects: Chemistry; Organic Chemistry; Polymer Chemistry; Polymers

Master of Science, University of Akron, 2018, Polymer Engineering

Aerogel is a synthetic nanoporous functional material with abundant unique properties, such as ultralow thermal conductivity and ultralow modulus. Many achievements were reported about silica aerogel, however, related researches on polymer aerogel are not deep enough, especially for d form syndiotactic polystyrene (sPS) aerogels. This research investigated at the modification of sulfonated syndiotactic polystyrene aerogels, through an ion-exchange reaction with semi-telechelic, quaternary phosphonium functionalized poly (tert-butyl styrene) (PtBS) synthesized by reversible addition fragmentation chain transfer (RAFT) agent. Synthesis and purification of ionic PtBS were key factors in this research, which also involves the synthesis of ion-containing RAFT agent. The end group functionality of PtBS was examined by thin layer chromatography (TLC) and purification was achieved by column chromatography. Syndiotactic polystyrene (sPS) was sulfonated with acetyl sulfate reagent and neutralized with methanolic sodium hydroxide. The H1 NMR and FT-IR were used for characterization, which verified the chemical structure of RAFT agent, PtBS, sulfonated syndiotactic styrene and SsPS-PtBS aerogels.

Committee: Kevin Cavicchi (Advisor); Sadhan Jana (Advisor); Zacharia Nicole (Committee Chair) Subjects: Polymer Chemistry; Polymers

Doctor of Philosophy, University of Akron, 0, Polymer Engineering

This dissertation focused on the synthesis, characterization, and applications of the low-cross-link density poly acrylates elastomers using direct RAFT cross-linker. Also, the design and evaluation of the high-throughput polymerization system was studied by the kinetic study of PS and PBA. Synthesis of the direct cross-linker and preparation of the low cross-link density elastomers were achieved in one-pot synthesis. First, we report a newly developed custom-built high-throughput polymerization robot which is one of the promising fields to optimize the polymerization reaction of a polymer. A custom-built manifold to purge reaction vials to inert atmosphere and a rotary evaporator adapter holding up to 24 samples with a greater than 900 % enhanced efficiency than single evaporation is described. The validation of the high-throughput polymerization robot was performed by the RAFT polymerization of the PS and PBA and showed a good agreement with both previously reported results by other high-throughput polymerization systems and the standard laboratory techniques. Second, low cross-link density of the polyacrylate gels were synthesized, and characterized via the swelling and the rheology. Different target cross-link density of the PBA from 1.5 to 410 mol/m3 and PODA gels from 2.9 to 193 mol/m3 were prepared with the direct RAFT cross-linker, conventional cross-linker, and RAFT agent and conventional cross-linker mixture in either bulk or solution polymerization using diluent solvent. As a result, gels prepared with the direct RAFT cross-linker exhibited up to 200 % improved swelling than conventional gels, resulting in lower cross-link density and the enhanced mechanical properties. Calculated cross-link density using Flory-Rehner model with the phantom network, showed a good agreement to the target cross-link density of gels prepared with direct RAFT cross-linker. Also, lightly cross-linked PODA gels showed the potential applicant as oil absorbent. As ano (open full item for complete abstract)

Committee: Kevin Cavicchi (Advisor); David Simmons (Committee Chair); Sadhan Jana (Committee Member); Chrys Wesdemiotis (Committee Member); Yu Zhu (Committee Member) Subjects: Polymer Chemistry; Polymers

Master of Sciences, Case Western Reserve University, 2017, Macromolecular Science and Engineering

Firstly, a commercial flow reactor was used to synthesize poly(PEGMEMA) via RAFT polymerization. The tunable pressure makes it possible to conduct polymerization at high temperature in aqueous solution. Compared with the same reaction in conventional batch reactor, this flow system can lead to higher polymerization efficiency. The flow rate and initiator concentration were also well studied to tune the monomer conversion and the molar mass dispersity (Ð) of the obtained polymers. Poly(PEGMEMA) and poly(PEGMEMA)-b-PNIPAM brushes were also grafted from the silica microparticles by such continuous system at high temperature with increased pressure. The flowing nature makes it possible to conduct multi-step reactions with simple purification process which saves time and cost. TGA, FT-IR, SEM were utilized to characterize the polymer modified microparticles. GPC and NMR were also used to measure the brushes cleaved from particles.

Committee: Rigoberto Advincula (Advisor); Lei Zhu (Committee Member); Jon Pokorski (Committee Member) Subjects: Chemistry; Polymer Chemistry; Polymers

Master of Science, Miami University, 2016, Chemistry and Biochemistry

Biomacromolecules made by covalent attachment of polymers to the surfaces of proteins are an interesting area of research with significant applications in drug therapies and growing interest in energy and nanotechnology. Protein-polymer conjugates are typically synthesized by either the grafting-to or grafting-from approach. In grafting-to, polymer is separately synthesized and characterized prior to linkage to the protein. However, in grafting-from, an initiating group is attached to the protein, which allows for growth of the polymer directly from the protein surface. Herein, a hybrid approach is used, combining the advantages of both conjugation techniques. RAFT polymerization is used to grow water soluble polymers for grafting-to and subsequent chain extension from enzymes of interest. First, conjugates made from the well-studied, model enzyme lysozyme are discussed. Next, cellulase-polymer conjugates with potential applications in biofuel production are explored. In these studies, the impact of polymer size and functional groups on enzymatic activity, thermal and chemical stability are investigated. Important trends gleaned from this work contribute to the understanding of structure-property correlations in protein-polymer conjugates. These relationships are critical to the advancement of protein-polymer conjugates in efforts to produce engineered biomacromolecules with tunable behaviors for specific applications.

Committee: Dominik Konkolewicz (Advisor); C. Scott Hartley (Committee Chair); Richard C. Page (Committee Member); Jason A. Berberich (Committee Member) Subjects: Biochemistry; Chemistry; Organic Chemistry; Polymer Chemistry

Master of Science, University of Akron, 2016, Polymer Engineering

A halatopolymer is a class of ionically-bonded materials that display both salt-like and polymer-like properties. Due to the presence of the ionic-bond in the main polymer chain, halatopolymers show some unique thermal and mechanical properties. Reversible Addition Fragmentation chain Transfer (RAFT) polymerization is a kind of controlled free radical polymerization which has been widely used in the synthesis of homopolymers or block copolymers. Trithiocarbonates (TTC) compounds have played an essential role in RAFT polymerization as chain transfer agents. In this work, the concepts of halatopolymers and RAFT polymerization have been combined by using carboxylic acid-terminated trithiocarbonate RAFT agent to synthesis trithiocarbonate-containing halatopolymers. The 1H NMR spectra and FTIR spectra confirmed the successful synthesis of trithiocarbonate-containing halatopolymers. Then these trithiocarbonate-containing halatopolymer were used as RAFT agents to synthesize halato carboxy-telechelic polystyrene homopolymers by solution polymerization. TGA, GPC and viscosity tests were used to characterize the structure and properties of the halato carboxy-telechelic polystyrenes. The calcium carboxy-telechelic polystyrene-b-poly(n-butyl acrylate)-b-polystyrene triblock copolymers were synthesized by using calcium carboxy-telechelic polystyrenes as RAFT agents. Thermal and rheological properties of these polymers were characterized, where the intermolecular ionic interactions strongly influence the mechanical properties compared to the non-ionic ABA triblock copolymers.

Committee: Kevin Cavicchi (Advisor); Nicole Zacharia (Committee Member); David Simmons (Committee Chair) Subjects: Polymer Chemistry; Polymers

Master of Science, Miami University, 2015, Chemical, Paper and Biomedical Engineering

Proteins and enzymes have long been used in a wide variety of applications from laundry detergents to therapeutics; however, instability under conditions such as high temperature, extreme pH, organic solvents, and the presence of proteases limit new applications.Combining natural proteins with synthetic polymers to create protein-polymer conjugates offers the opportunity to create new functional materials with improved activity and stability. In this study, random and site-specifically modified protein-polymer conjugates were synthesized by RAFT polymerization using grafting-to and grafting-from approaches. Polymer conjugates of the model proteins, lysozyme and chymotrypsin, were synthesized by random modification and the enzyme activity, stability, and number of attachments were determined. Site-specific modification of green fluorescent protein was achieved using the LAP/Lipoic Acid Ligase system and RAFT polymerization. These bioconjugates were characterized to determine the number of CTA attachments and polymer length.

Committee: Jason Berberich (Advisor); Richard Page (Committee Member); Dominik Konkolewicz (Committee Member); Jessica Sparks (Committee Member) Subjects: Chemical Engineering

Doctor of Philosophy, The Ohio State University, 2015, Chemistry

This dissertation describes the synthesis and assembly of bio-functional polymers and the applications of these polymers to drug encapsulation, delivery, and multivalent biomimetic macromolecular recognition between synthetic polymer and nucleic acids. The main content is divided into three parts: (1) polyacidic domains as strongly stabilizing design elements for aqueous phase polyacrylate diblock assembly; (2) small molecule/polymer recognition triggered macromolecular assembly and drug encapsulation; (3) trizaine derivatized polymer as a novel class of “bifacial polymer nucleic acid” (bPoNA) and applications of bPoNA to nanoparticle loading of DNA/RNA, silencing delivery as well as control of aptamer function. Through the studies in part (1) and part (2), it was demonstrated that well-designed polymer motifs are not only able to enhance assemblies driven by non-specific hydrophobic effect, but are also able to direct assemblies based on specific recognitions. In part (3) of this dissertation, this concept was further extended by the design of polyacrylate polymers that are capable of discrete and robust hybridization with nucleic acids. This surprising finding demonstrated both fundamental and practical applications. Overall, these studies provided insights into the rational design elements for improving the bio-functions of synthetic polymers, and significantly expanded the scope of biological applications in which polymers synthesized via controlled radical polymerization may play a role.

Committee: Dennis Bong Dr. (Advisor); Jovica Badjic Dr. (Committee Member); Psaras McGrier Dr. (Committee Member) Subjects: Chemistry

Doctor of Philosophy, University of Akron, 2015, Polymer Engineering

Alkyds are polyesters derived from oils, dibasic acids and polyols and one of the most commonly used binders for several coating applications such as architectural and wood coatings. Conventional solvent-borne alkyd coatings generally contain 30-60 wt% solvents which contribute to hazardous volatile organic compounds (VOCs) emission. This dissertation focused on the development of high-solid alkyd coating systems with reduced VOC content. This was done by the substitution of organic solvents in coating formulations by using reactive diluents derived from renewable materials. Soybean oil was modified in two steps: 1) conjugation of soybean oil, 2) Diels-Alder addition with 3-(trimethoxysilyl)propyl methacrylate, 2,2,2-trifluoroethyl methacrylate, and triallyl ether acrylate. The structures were characterized using 1H NMR, 13C NMR, 13C-1H gradient heteronuclear single quantum coherence (gHSQC) NMR spectroscopy and MALDI-TOF mass spectrometry. The 13C-1H gHSQC NMR spectra confirmed the formation of a cyclohexene ring in all reactions, indicating a Diels-Alder addition. A long oil soy-alkyd was formulated with three modified soybean oils. Allyl ether-functionalized soybean oil resulted in the highest reduction in the viscosity of the alkyd formulations. The siloxane and allyl ether-functionalized soybean oil enhanced the tensile modulus and crosslink density by 20 % and 70 %, respectively. Coatings with fluorine-functionalized soybean oil showed enhanced contact angle and solvent resistance, compared to alkyd coatings. Alkyd-acrylic hybrid coatings are gaining considerable attention due to their ability to combine the beneficial properties of both. Alkyd-acrylic copolymers were synthesized using a combination of step polymerization and reversible addition fragmentation transfer (RAFT) polymerization. FT-IR studies indicated that the autoxidative curing of RAFT polymerized alkyd-acrylic coatings was hindered. A model compound study showed that thiocarbonyl function (open full item for complete abstract)

Committee: Mark Soucek Dr. (Advisor); kevin Cavicchi Dr. (Committee Member); Thein Kyu Dr. (Committee Member); Coleen Pugh Dr. (Committee Member); Chys Wesdemiotis Dr. (Committee Member) Subjects: Polymers

PhD, University of Cincinnati, 2014, Arts and Sciences: Chemistry

This dissertation details the synthesis and characterization of N-alkyl-N,N-linked urea oligomers and their incorporation into glycosaminoglycan mimicking polymers. N-alkyl-N,N-linked urea oligomers are oligomers that can incorporate a wide variety of functional side chains and are prepared through standard organic chemistry techniques. Polymers in this thesis were synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. RAFT polymerization is a controlled/“living” radical polymerization technique that can be used to prepare (co)polymers of controlled molecular weights and narrow polydispersities. The N-alkyl-N,N-linked urea oligomer containing polymers have been designed to mimic the properties of the naturally occurring anticoagulant GAG molecule heparin through incorporation of sulfonated carbohydrates as N-alkyl side groups. Heparin is a naturally occurring heterogeneous, sulfated, anionic sugar macromolecule that is commonly used as a therapeutic anticoagulant. In the second chapter, N-alkyl-N,N-linked urea oligomers containing terminal alkyne units were modified with monomeric saccharides. In third chapter, copper catalyzed azide-alkyne cycloaddition (CuAAC) or “click” chemistry is used to synthesize a universal N-alkyl-N,N-linked urea oligomer that allows for the quick and simple synthesis of several oligomers bearing different monomeric saccharides. In the fourth chapter, more complex saccharide units are incorporated and sequence specificity is built in to the universal N-alkyl-N,N-linked urea oligomer of chapter 3 by utilizing simple protecting group chemistry to allow for the step-wise modification of the N-alkyl urea peptoid oligomer backbone.

Committee: Neil Ayres Ph.D. (Committee Chair); Patrick Limbach Ph.D. (Committee Member); David Smithrud Ph.D. (Committee Member) Subjects: Polymers

Doctor of Philosophy, University of Akron, 2014, Polymer Engineering

Supramolecular block copolymers, which are the supramolecular analog of covalently-bonded block copolymers, consist of individual polymer blocks connected by non-covalent bonds. They can be produced by self-assembly of telechelic oligomers or polymers with complementary end-groups, e.g., hydrogen bonding or acid-base interactions, such that a variety of block combinations may be achieved by simple mixing of the appropriate polymers. Supramolecular block copolymers are advantageous for fabricating nanostructured functional materials, since they can exhibit morphologies mimicking conventional covalently-bonded block copolymers and the reversible nature of the supramolecular bonds between blocks allows for unique responses to external stimuli. Various applications of these materials have been explored, such as self-healing, thermally tunable nanostructures, nanoporous materials, and nanostructured assemblies. In the first part, a supramolecular multiblock copolymer, was synthesized by mixing two telechelic oligomers, a,¿-sulfonated polystyrene, HO3S-PS-SO3H, derived from a polymer prepared by reversible addition-fragmentation chain-transfer (RAFT) polymerization, and a,¿-amino-polyisobutylene, H2N-PIB-NH2, prepared by cationic polymerization. During solvent casting, proton transfer from the sulfonic acid to the amine formed ionic bonds that produced a multiblock copolymer that formed free-standing flexible films with a modulus of 90 MPa, a yield point at 4% strain and a strain energy density of 15 MJ/m3. Small angle X-ray scattering characterization showed a lamellar morphology, whose domain spacing was consistent with the formation of a multiblock copolymer based on comparison to the chain dimensions. A reversible order-disorder transition occurred between 190°C and 210°C, but the sulfonic acid and amine functional groups decomposed at those elevated temperatures based on companion optical microscopy and spectroscopy measurements. For high non-linear strains, the (open full item for complete abstract)

Committee: Robert Weiss Dr. (Advisor); Kevin Cavicchi Dr. (Advisor); Alamgir Karim Dr. (Committee Member); Coleen Pugh Dr. (Committee Member); Wiley Youngs Dr. (Committee Member) Subjects: Plastics