Polymer Chemistry Commons^™

Sequence-Defined Ionic Peptoid Block Copolymers: Synthesis And Solution Self-Assembly, Garrett Leigh Sternhagen

LSU Doctoral Dissertations

This work covers efforts to develop a peptoid-based model system for systematically studying the role of ionic functional groups in determining the structure of ionic block copolymer (BCP) self-assemblies in water. A key challenge in the study of polyelectrolytes is the lack of synthetic control over the location of ionic monomers along a polymer chain. We developed a model system based on sequence-defined ionic peptoid BCPs having discrete chain length and precisely positioned ionic monomers along the chain to specifically address this issue. In Chapter 1, synthetic strategies to access well-defined polypeptoids and their application in BCP synthesis are reviewed. …

Synthesis And Characterization Of Multifunctional Transition Metal Oxide Nanoparticles Through A Modified Sol-Gel Method With Application In Energy Storage, Julien Lombardi

Dissertations, Theses, and Capstone Projects

The Synthesis of transition metal oxide nanoparticles has been studied in great detail over the many years. The most studied transition metal oxide nanoparticles are perovskites of the ABO₃ stoichiometry (A and B = transition metal) and more recently double perovskite crystal structures of the AA’BO₆ or A₂BB’O₆ stoichiometry due to the many different properties arising from the many different combinations of elements possible. These materials have proven potentially useful in many fields, but due to properties such as ferroelectricity and ferromagnetism, the desire to integrate these materials into electronics is ever growing. Many synthesis …

Synthesis Of Unsymmetrical Bis(Phosphine) Oxides And Their Phosphines Via Secondary Phosphine Oxide Precursors, James R. Pedroarena, Bryan P. Nell, Lev N. Zakharov, David R. Tyler

Chemistry Publications

The unsymmetrical bidentate phosphine ligands (Me)₂PCH₂CH₂CH₂P(Et)₂ (14), (Me)₂PCH₂CH₂CH₂P(iPr)₂ (15), (Me)₂PCH₂CH₂CH₂P(Cy)₂ (16), and (Me)₂PCH₂CH₂CH₂P(Ph)₂ (17) were synthesized using air–stable phosphine oxide intermediates. In the first step, sodium phosphinites formed by deprotonation of (Me)₂P(O)H, (Et)₂P(O)H, and (iPr)₂P(O)H were alkylated by 1-bromo-3-chloropropane. The different substitution rates of the chloride and bromide groups allowed the isolation of the intermediates (Me)₂P(O)CH …

Organic-Inorganic Hybrid Composites: Superhydrophobic Polymer Coatings With Photoreactive Perfluorinated Phthalocyanines, Abdul Azeez

Seton Hall University Dissertations and Theses (ETDs)

ABSTRACT

We report partly fluorinated and silicon-based polymers that incorporate inorganic/organic materials capable of generating reactive oxygen species (ROS) using only visible light and air. Polyvinylidene fluoride (PVDF), which incorporated a known perfluorinated phthalocyanine photosensitizer, F₆₄PcZn, supported on silicon and titanium oxides was further modified via chemical surface roughening to exhibit enhanced hydrophobicity when used as a coating. Water contact angles as high as ~159° have been observed, vs. ~ 92° for the unmodified polymer. The polymer matrix, however, does not resist the ROS it produces as evidenced by spectroscopic and SEM data. A polysiloxane matrix was similarly …

Modification And Optimization Of Conducting Polymer-Modified, Redox-Magnetohydrodynamics (R-Mhd) Pumping For Enhanced And Sustained Microfluidics Applications, Md Foysal Zahid Khan

Graduate Theses and Dissertations

In this work, a novel microfluidic pumping approach, redox-magnetohydrodynamics (R-MHD) has improved by materials and device optimization to use in lab-on-a-chip applications. In R-MHD, magnetic flux (B) and ionic current density (j) interacts to generate body force (FB) in between active electrodes, according to the equation FB = j×B. This unique fluid pumping approach is scalable, tunable, generates flat flow profile, and does not require any channels or valves. Pumping performance, such as speed scales with the ionic current density (j) and duration depends on the total charge (Q). The ionic current density (j) results from the conversion of electronic …

Synthesis Of New Aliphatic Pseudo-Branched Polyester Co-Polymers For Biomedical Applications, Zachary Shaw

Electronic Theses & Dissertations

In this study, a hyperbranched polyester co-polymer was designed using a proprietary monomer and diethylene glycol or triethylene glycol as monomers. The synthesis was carried out using standard melt polymerization technique and catalyzed by p-Tolulenesulfonic acid. The progress of the reaction was monitored with respect to time and negative pressure, with samples being subjected to standard characterization protocols. The resulting polymers were purified using the solvent precipitation method and characterized using various chromatographic and spectroscopic methods including GPC, MALDI-TOF, and NMR. We have observed polymers with a molecular weight of 29,643 kDa and 33,996 kDa, which is ideal to be …

Photoswitchable Self-Complementary Hydrogen Bond Arrays, Suendues Noori, James A. Wisner

Western Research Forum

Background: Photochromism is the reversible transformation of a chemical material to another form by the absorption of electromagnetic radiation (light), where the two metastable forms have distinct absorption spectra and other properties. Photochromism in materials allows for the switching of their function solely based on irradiation with light. Polymers are used frequently as the building blocks for materials as they are versatile, multifunctional, can carry charge and be processed by solution-based deposition methods. Supramolecular polymers share the same definition as polymers with the exception that they are held together by reversible and directional non-covalent interactions such as hydrogen bonds. Synthesizing …

Non-Einstein Viscosity Phenomenon Of Acrylonitrile–Butadiene–Styrene Composites Containing Lignin–Polycaprolactone Particulates Highly Dispersed By High-Shear Stress, Sing-Hoon Kim, Kisuk Choi, Kyouk Ryeol Choi, Taesung Kim, Jonghwan Suhr, Kwang Jin Kim, Hyoung Jin Choi, Jae-Do Nam

Mechanical Engineering Faculty Research

Lignin powder was modified via ring-opening polymerization of caprolactone to form a lignin–polycaprolactone (LPCL) particulate. The LPCL particulates were mixed with an acrylonitrile–butadiene–styrene (ABS) matrix at an extremely high rotational speed of up to 3000 rpm, which was achieved by a closed-loop screw mixer and in-line melt extruder. Using this high-shear extruding mixer, the LPCL particulate size was controlled in the range of 3395 nm (conventional twin-screw extrusion) down to 638 nm (high-shear mixer of 3000 rpm) by altering the mixing speed and time. The resulting LPCL/ABS composites clearly showed non-Einstein viscosity phenomena, exhibiting reduced viscosity (2130 Pa·s) compared to …

Implementation Of Multivariate Artificial Neural Networks Coupled With Genetic Algorithms For The Multi-Objective Property Prediction And Optimization Of Emulsion Polymers, David Chisholm

Master's Theses

Machine learning has been gaining popularity over the past few decades as computers have become more advanced. On a fundamental level, machine learning consists of the use of computerized statistical methods to analyze data and discover trends that may not have been obvious or otherwise observable previously. These trends can then be used to make predictions on new data and explore entirely new design spaces. Methods vary from simple linear regression to highly complex neural networks, but the end goal is similar. The application of these methods to material property prediction and new material discovery has been of high interest …

Rheological Investigations Of Latex-Surfactant-Associative Thickener Aqueous Systems, Bishop I. Hammack

Master's Theses

Surfactants and Thickeners are both additives used in fully-formulated waterborne coatings to provide colloidal stability, thickening, and other functionality. The behavior of each ingredient in a coating must be understood and controlled to maintain colloidal stability as well as balance other desired properties of the liquid coating and the dry paint film. In this work, quaternary systems of Water-Latex-Thickener-Surfactant were investigated to further the understanding of their behavior in coatings. The thickener used was a well characterized, hydrophobically-modified, ethoxylated urethane (HEUR) with two C18 terminal hydrophobes and 795 average repeat units of ethylene oxide as the hydrophilic spacer. Two latexes, …

Hypervalent Iodine(Iii) Compounds With (Pseudo)Halide And Tetrazole Ligands In The Synthesis Of Functional Polymers, Rajesh Kumar

Chemistry Theses and Dissertations

The organic compounds of iodine(III) with the general formula ArIL₂ (Ar = aryl, L = (pseudo) halides) degrade homolytically upon irradiation or heating to the corresponding monovalent iodine compound (ArI) and the radicals L^• . If the latter contains a functional group, they can be used to initiate the polymerization of vinyl monomers to afford chain end-functionalized linear polymers. When "conventional" monovinyl monomers are copolymerized with di- or multivinyl monomers (crosslinkers) in the presence of relatively high concentrations of rapidly decomposing ArIL₂ compounds, highly branched polymers are formed that contain multiple chain-end functionalities derived from the radicals …

Melt Electrospinning Designs For Nanofiber Fabrication For Different Applications, Yasseen S. Ibrahim, Essraa A. Hussein, Moustafa M. Zagho, Ghada G. Abdo, Ahmed A. Elzatahry

Faculty Publications

Nanofibers have been attracting growing attention owing to their outstanding physicochemical and structural properties as well as diverse and intriguing applications. Electrospinning has been known as a simple, flexible, and multipurpose technique for the fabrication of submicro scale fibers. Throughout the last two decades, numerous investigations have focused on the employment of electrospinning techniques to improve the characteristics of fabricated fibers. This review highlights the state of the art of melt electrospinning and clarifies the major categories based on multitemperature control, gas assist, laser melt, coaxial, and needleless designs. In addition, we represent the effect of melt electrospinning process parameters …

Nanomedicine-Based Immunochemotherapy For The Mr Imaging And Treatment Of Triple Negative Breast Cancer, Saloni Darji

Electronic Theses & Dissertations

Cancer is known to be a detrimental disease and it accounts for many deaths every year. In women Triple negative breast cancer (TNBC) known to be a very aggressive type of tumor. Current treatment approaches are abortive and have many side effects. With the recent advances in nanotechnology and immunotherapy for cancer treatment, we have designed new nanomedicine that combines both the aspects of cancer treatment. In this work, we have developed an anti-PD-L1-conjugated, Doxo-SS-Gd MR imaging agent encapsulating iron oxide nanoparticles (IONPs) to form IONP-Doxo-SS-Gd-PD-L1 nanomedicine for the targeted MR imaging and treatment of TNBC. The anti-PD-L1 acts as …

High Performance Carbon Derived From Soybean Waste For Energy Storage Applications, Chen Zhao

Electronic Theses & Dissertations

The ever-increasing energy demands of daily life by devices such as portable electronics, vehicle equipment, and medical instruments stimulate development of highly efficient, cost-effective, and non-polluting materials for energy storage applications. Bio-based carbon material is the most promising and greenest class of electrodes based on the principle of the electrical double layer capacity, which has many merits such as high efficiency, long lifespan, fast charge-discharge rate, etc. for energy storage devices. In this study, combining carbonization and chemical activation processes through KOH, micropore and mesopore structures of soybean shells, stems, and leaves are successfully synthesized. Physical morphology and structures of …

Thermotropic Liquid-Crystalline And Light-Emitting Properties Of Poly(Pyridinium) Salts Containing Various Diamine Connectors And Hydrophilic Macrocounterions, Tae Soo Jo, Haesook Han, Pradip K. Bhowmik, Benoît Heinrich, Bertrand Donnio

Chemistry and Biochemistry Faculty Research

A set of poly(pyridinium) salts containing various diamine moieties, as molecular connectors, and poly(ethyleneglycol)-4-nonylphenyl-3-sulfopropyl ether, thereafter referred to as “Macroion”, as the hydrophilic counterion, were prepared by metathesis reaction from the respective precursory tosylated poly(pyridinium)s in methanol. The structure of these ionic polymers was established by spectroscopy and chromatography techniques. The shape-persistent ionic poly(pyridinium) materials, inserting rigid or semi-rigid diamine spacers, display thermotropic liquid-crystalline properties from room-temperature up to their isotropization (in the temperature range around 160–200 °C). The nature of the LC phases is lamellar in both cases as identified by the combination of various complementary experimental techniques including …

Modifying Inhibited Primer Performance Via Control Of Epoxy-Amine Matrix Structure And Composition, Steven Wand

Dissertations

This research represents an effort to deliver a new fundamental understanding of how polymer matrix characteristics influence corrosion protection of organic coatings, in particular the performance of corrosion inhibitor-containing primers. By modifying the structure and composition features of epoxy-amine matrices which commonly serves as the binder for protective coatings, the thermal/mechanical, adhesion, and transport properties which govern coating performance and inhibitor release were altered in such a way that directly influenced protection efficacy. This research is composed of three distinct approaches towards systematically varying thermoset network characteristics and observing the resulting impact on transport behaviors and corrosion prevention, with an …

“Polysoaps” Via Raft Copolymerization To Form Well-Defined Micelles For Water Remediation And Targeted Drug Delivery Applications, Phillip Pickett

Dissertations

Amphiphilic copolymers have become increasingly important for environmental and biological applications due to their behavioral characteristics in aqueous solution. For example, structurally-tailored statistical amphiphilic copolymers or “polysoaps” can self-assemble into micelles or other architectures in water at various concentrations. Polysoaps may be differentiated from small molecule surfactant micelles in their capability to self-assemble into unimolecular associates (unimolecular micelles) with no dependence on concentration. Such micelles offer enormous potential for dispersion of hydrophobic species in water at high dilution. Importantly, each polymer chain forms its own micelle and upon dilution, these micelles remain intact and capable of dispersing hydrocarbon material in …

Engineering Multifunctional And Morphologically Diverse Polymer Brush Surfaces, Cassandra M. Reese

Dissertations

The combination of surface-initiated polymerization (SIP) and post-polymerization (PPM) serves as a powerful approach to fabricate complex, multifunctional polymer films, which can be precisely tuned for desired surface engineering applications. Careful manipulation of PPM parameters such as reaction conditions, the tethered brush parameters, and the physical properties of the unbound post-modifier greatly influence the depth of penetration of the post-modifier and the polymer brush compositional heterogeneity. This dissertation focuses on engineering polymer brush surfaces with multifunctional chemistries and tunable morphologies by investigating the PPM parameters that dictate the distribution of post-modifiers on grafted polymer brush surfaces.

The first chapter of …

Evaluating Corrosion Altering Properties Of Thiophene Based Copolymers, Robert Peterson

Dissertations

There is an important and ongoing debate on how or whether conductive polymers (CP) alter corrosion performance with some researchers reporting that CPs ultimately accelerate corrosion and others saying CPs, if understood could possibly replace the world’s best standard for corrosion prevention, i.e., chromium based inhibitors. The primary project goal was to improve our understanding of how CPs alter corrosion chemistry by 1) controlling the polymer structure and 2) in-turn the properties and then 3) targeting the best protocol for fast corrosion kinetic evaluation.

We detail the copolymer synthesis results and shift in corrosion protection properties for …

Synthesis, Characterization, And Utilization Of Iron Ii Ion Sensing Fluorescent Probes For Detection Of Early Onset Anodic Corrosion, Dane N. Wedgeworth

Honors Theses

Corrosion effects can be seen in infrastructure all around the world. From rusted bridges, ships, and other steel surfaces, the price of corrosion adds up quickly with repairs, maintenance, and complete replacement. Common approaches to corrosion detection and prevention require slow, optical inspection to begin the repair and maintenance process, which can also be very slow and costly. However, recent literature suggests that metal chelating probes can yield new understanding of the processes of corrosion faster and with greater specificity in location and diversity in mechanisms for early onset of corrosion. Earlier corrosion detection can be characterized by several ways. …