Polymer Chemistry Commons^™

Frontiers In The Self-Assembly Of Charged Macromolecules, Khatcher O. Margossian

Doctoral Dissertations

The self-assembly of charged macromolecules forms the basis of all life on earth. From the synthesis and replication of nucleic acids, to the association of DNA to chromatin, to the targeting of RNA to various cellular compartments, to the astonishingly consistent folding of proteins, all life depends on the physics of the organization and dynamics of charged polymers. In this dissertation, I address several of the newest challenges in the assembly of these types of materials. First, I describe the exciting new physics of the complexation between polyzwitterions and polyelectrolytes. These materials open new questions and possibilities within the context …

Intracellular Delivery Of Therapeutic Biomolecules Through Versatile Polymer Nanotechnology, David C. Luther

Doctoral Dissertations

Advancing pharmaceutical technology has made it possible to treat diseases once considered ‘undruggable.’ Access to these new pharmaceutical targets is possible thanks to the advent of protein and nucleic acid therapeutics. Responses to the COVID-19 pandemic, as well as cutting-edge treatments for cancer and multiple sclerosis have centered on these biologic therapies, promising even greater value in the future. However, their utility is limited at a cellular level by inability to cross the plasma membrane. Nanocarrier technologies encapsulate therapeutics and facilitate uptake into the cell but are often trapped and degraded in endosomes. Arginine-functionalized gold nanoparticles (Arg-NPs) provide efficient, direct …

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 …

Converting Hydrazone-Based Photoswitches Into Functional Materials, Sirun Yang

Dartmouth College Ph.D Dissertations

The development of new classes of molecular switches with enhanced performance and brand-new functionalities enables practitioners to push the frontiers of adaptive materials. In the realm of photoswitches, the bistability of hydrazones (i.e., molecules that incorporate the C=N-NH functional group) allows for the kinetic trapping of polymer and supramolecular assemblies resulting in multistate actuation and emergent phenomena that are not tractable with other photoswitches. This property has transformed hydrazone photoswitches into powerful tools that can be used in understanding fundamental molecular interactions and how to apply them in modulating the physicochemical properties of materials.

Progressing from disordered to …

Enabling Nanoimprint Lithography Techniques Across Multiple Manufacturing Processes, Vincent Einck

Doctoral Dissertations

Advanced nanooptics in the areas of flat lenses, diffractive elements, and tunable emissivity require a route to high throughput manufacturing. Nanooptics are often demanding of high refractive index materials, nanometer precision and ease of fabrication. Nanoimprint lithography (NIL) is a low-cost, high throughput manufacturing technique beginning to be realized in commercial industry.^1,2 The NIL process is an ideal manufacturing candidate due to its ability to have a fast process time, efficient use of materials, repeatability and high precision while also having wide diversity of potential structures and material choices. Appling NIL techniques to other facets of manufacturing enable the …

Conformation Of The U12-U6atac Snrna Complex Of The Minor Spliceosome And Binding By Ntc-Related Protein Rbm22, Joanna Ciavarella

Dissertations, Theses, and Capstone Projects

Splicing of precursor messenger (pre-m)RNA is a critical process in eukaryotes in which the non-coding regions, called introns, are removed and coding regions, or exons, are ligated to form a mature mRNA. This process is catalyzed by the spliceosome, a multi-mega Dalton ribonucleoprotein complex assembled from five small nuclear ribonucleoproteins (snRNP) in the form of small nuclear (sn)RNA-protein complexes (U1, U2, U4, U5 and U6) and >100 proteins. snRNA components catalyze the two transesterification reactions while proteins perform critical roles in assembly and rearrangement. U2 and U6 snRNAs are the only snRNAs directly implicated in catalyzing the splicing of pre-mRNA. …

Polyaniline-Derivatives Based On Poly (Heterocyclic Diphenylamine) With Improved Electrochemical Stability And Processability, Mohammed Noifa Almtiri

Theses and Dissertations

Today, smart innovation has become an essential part of human life; thus, contemporary technologies are always looking for intelligent, responsive, and efficient materials to satisfy these demands. Consequently, synthetic "metals" or, more precisely, intrinsically conducting polymers (CPs) have begun to find a place as valuable and practical materials for a new generation of devices. Amongst all intrinsic conducting polymers, polyaniline (PANI) has attracted significant attention due to its outstanding air and moisture stability, simple preparation technique, and high electrical conductivity (chapter I).

Chapter II represents the synthesis of a new PANI derivative that contains a phenoxazine unit co-polymerized with p-phenylenediamine …

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 …

How Dynamic Bond Results In The Unique Viscoelastic Behavior Of The Associating Polymers, Sirui Ge

Doctoral Dissertations

Associating polymer is a special kind of polymer possessing transient reversible bonds in addition to the conventional covalent bonds. The reversible bonds provide unique dynamics and fascinating viscoelastic properties, resulting in attractive applications for these polymers, such as self-healing and shape memory materials. Despite many years of studies, the understanding of dynamics of polymers with reversible bonds, especially on molecular level, is still in the rudimentary stage, preventing the rational design of the potential novel functional materials based on associating polymers. In this dissertation, we provide a detailed and quantitative understanding of the dynamics and viscoelastic properties of associating polymers. …

Polynorbornenes For Advanced Applications And Processes, Xinyi Wang

Doctoral Dissertations

Polynorbornenes have dramatically different properties and various applications depending on their chemical structures. The modular nature of norbornene-based systems provides a facile route toward synthesizing diverse polymeric materials, thus making them ideal materials for systematic structure-property investigations. Herein, their application as gas separation membranes and the correlation between their gas-transport properties and polymer structures will be investigated. Though many valuable correlations between gas-permeability and polynorbornene structure have been studied previously, many of these efforts have focused heavily on designing materials with various chemical structures to achieve high permeabilities. In contrast, the influence of molecular structure on: a) polynorbornene chain packing …

Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are
(a) a one-piece base for the standard kit's (Martin-style) bracing,
(b) 277 Ladder-style bracing, and
(c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.

The CADD data set for each of the three (3) top bracing designs includes …

Designing Dynamic And Degradable Polymeric Materials With Thiol-X Chemistries, Reese Sloan

Dissertations

With plastic production poised to increase in coming years, there arises a need to develop new polymeric materials designed to combat the global pollution crisis. A commonly utilized approach in addressing this challenge is to employ a responsive functional moiety into the polymer architecture. Thiol-X reactions, a commonly utilized class of “click” reactions, have garnered broad implementation in new stimuli-responsive materials. This work specifically focuses on utilizing radical-mediated thiol-ene coupling and base-catalyzed thiol-isocyanate reactions to develop a library of ternary thiol-ene/thiourethane covalent adaptable networks (CANs) and hydrolytically labile poly(thioether ketal) thermoplastics. CANs are a class of network materials capable of …

Synthesis, Structure-Activity And Mechanism Studies Of Poly(Guanylurea)S Against Mycobacteria, Michelle M. Miranda

FIU Electronic Theses and Dissertations

Tuberculosis (TB) continues to be a serious threat worldwide, especially in developing countries. Current first-line treatment for TB infections is a multidrug regimen for 4-9 months; if not taken as prescribed, drug-resistant TB can emerge. Novel drugs with unconventional targets are warranted to lessen the lengthy and four-drug treatment. Antimicrobial polymers mimicking naturally occurring antimicrobial peptides (AMPs) have gained much attention due to their enzymatic stability, tunability, cost-effectiveness, and unique mode of action - directly or indirectly - on bacterial membrane. However, selectivity and toxicity have limited their biological applications. Previously, our group synthesized a novel class of antimicrobial polymers, …

Designing Polymer-Protein Complexes For Intracellular Delivery, Hazel Davis

Doctoral Dissertations

Previous work in the Tew group has demonstrated polymer cell-penetrating peptide mimics (CPPMs) as effective transporters of biological agents, including proteins and antibodies. These synthetic polymers non-covalently bind to cargo, offering a mechanism to deliver proteins in a way that does not alter protein secondary structure. However, correlations of the protein binding-delivery relationship or the role of polymer-protein complexation on intracellular activity of protein cargo are understudied. The work presented herein connects a fundamental understanding of polymer-protein complexation with intracellular internalization and cargo activity. Characterization and quantification of polymer-protein binding relationships were established using fluorescence quenching assays. In particular, the …

Synthesis Of Phenyl Carbamoylated Guanidine Functionalized Chitosan, Eduardo Hernandez Requejo

FIU Electronic Theses and Dissertations

The lack of solubility of the chitosan in organic solvents hinders its potential for chemical modifications. For this reason, it was hypothesized that the insertion of the phenyl carbamoylated guanidine moiety could lead to increased solubility in DMSO and new potential modifications and uses.

This research involved the synthesis of S-methyl phenyl carbamoylated guanidine (SMPCG) starting from the commercially available S-methyl isothiourea. This was followed by the reaction of the SMPCG with chitosan to yield phenyl carbamoylated guanidine functionalized chitosan (PCGCs) with a degree of substitution of 14%.

The chitosan derivative is fully soluble in DMSO and partially in DMF. …

Modified Guanidine-Containing Polymers For Intracellular Protein Delivery, Alfonso Barrios

FIU Electronic Theses and Dissertations

Protein-based therapeutics have gained significant attention for treating or curing various diseases, especially those untreatable by small molecule-drugs. Despite their widespread success and adoption, the cellular membrane remains a major obstacle for proteins to reach the inner compartments of the cell and have had limited applicability spanning only extracellular targets. Consequently, the efficient intracellular delivery of proteins offers tremendous potential to reach new, unexplored, and otherwise “undruggable” targets. Acknowledging the therapeutic need, research efforts aimed at facilitating the delivery of proteins using polymer-based nanoparticles have emerged.

Guanidine-containing polymers provide a promising platform to address the common hurdles associated with protein …

Studies In The Use Of 1,1'-Di(1-Hydroxyethyl)Ferrocene As A Flame Retardant For Polyurethanes, Chanel Yeary

Electronic Theses & Dissertations

Significant research in non-toxic flame retardants (FR) has been performed in recent years since the dangerous consequences of halogenated FR were found. As early as the 1970’s, carcinogenic the side effects of halogenated compounds were being acknowledged. Since the early 2000’s halogenated FRs began being phased out of use due to these negative side effects. Since then, significant research has been exploring alternative effective flame retardants. Ferrocene (Fc) is a promising alternative to halogenated FRs due to its nontoxicity and FR properties. This research will report on the synthesis of 1,1’-di(1-hydoxyethyl) ferrocene (DHEFc) and its incorporation into a polyurethane. A …

Bbt Side Mold Assy, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass …

Biomass Estimation Of Marine Biofilms On Plastic Surfaces, Kian Banihashemi, Fernando Javier Gil

Biological Sciences

Plastics have become a major source of marine pollution, which threatens food safety and quality, human health, and marine ecosystems. Due to the drastic negative effects of plastics in a marine environment, alternative biodegradable plastics are being generated that are more eco-friendly and have less environmental impact. Though some of these plastics are known to biodegrade, the process of degradation for bioplastics has not been heavily studied in a marine environment. This pilot project sought to both quantify the process of biodegradation and compare across different methods for effectiveness of biomass estimation, which serves as an indicator of biodegradation. Plastics …

A Modular Synthesis Of Processable And Thermally Stable Semi-Fluorinated Aryl Ether Polymers Via Step-Growth Polymerization Of Fluoroalkenes, Ketki Eknath Shelar

Theses and Dissertations

Tailored fluoropolymers remain the leading choice for a wide variety of advanced high-performance applications, including electronic/optical and energy conversion, owing to their unique blend of complementary high-performance properties. Amorphous semi-fluorinated polymers exhibit improved solubility and melt processability when compared to traditional perfluoropolymers. A leading class of semi-fluorinated aryl ether polymers includes perfluorocyclobutyl (PFCB), perfluorocycloalkenyl (PFCA), and fluoroarylene vinylene ether (FAVE) polymers. Monomers containing aromatic trifluorovinyl ethers (TFVE) are used to synthesize PFCB polymers via radical-mediated [2+2] cyclodimerization. On the other hand, FAVE and PFCA polymers are polymerized via base-mediated nucleophilic addition/elimination of bisphenols with TFVE monomers and decafluorocyclohexene respectively. The …