Polymer Chemistry Commons^™

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 …

A High-Spin Ground-State Donor-Acceptor Conjugated Polymer, Alex E. London, H. Chen, M.A. Sabuj, Joshua Tropp, M. Saghayezhian, Naresh Eedugurala, B.A. Zhang, Y. Liu, Xiaodan Gu, B.M. Wong, N. Rai, M.K. Bowman, Jason D. Azoulay

Faculty Publications

Interest in high-spin organic materials is driven by opportunities to enable far-reaching fundamental science and develop technologies that integrate light element spin, magnetic, and quantum functionalities. Although extensively studied, the intrinsic instability of these materials complicates synthesis and precludes an understanding of how fundamental properties associated with the nature of the chemical bond and electron pairing in organic materials systems manifest in practical applications. Here, we demonstrate a conjugated polymer semiconductor, based on alternating cyclopentadithiophene and thiadiazoloquinoxaline units, that is a ground-state triplet in its neutral form. Electron paramagnetic resonance and magnetic susceptibility measurements are consistent with a high-to-low spin …

Using Green Emitting Ph-Responsive Nanogels To Report Environmental Changes Within Hydrogels: A Nanoprobe For Versatile Sensing, Mingning Zhu, Dongdong Lu, Shanglin Wu, Qing Lian, Wenkai Wang, L. Andrew Lyon, Weiguang Wang, Paulo Bártolo, Brian R. Saunders

Engineering Faculty Articles and Research

Remotely reporting the local environment within hydrogels using inexpensive laboratory techniques has excellent potential to improve our understanding of the nanometer-scale changes that cause macroscopic swelling or deswelling. Whilst photoluminescence (PL) spectroscopy is a popular method for such studies this approach commonly requires bespoke and time-consuming synthesis to attach fluorophores which may leave toxic residues. A promising and more versatile alternative is to use a pre-formed nanogel probe that contains a donor/acceptor pair and then “dope” that into the gel during gel assembly. Here, we introduce green-emitting methacrylic acid-based nanogel probe particles and use them to report the local environment …

Bridging The Molecular/Material Divide: An Investigation Into The Properties Of Polyesters, Terra Marie M. Jouaneh

Senior Honors Projects

By definition, polymers consist of large molecules composed of small, repeating units called monomers. These monomers give characteristic material properties to polymers, whether they be the melting point, the folding character, or the inherent stability. Many of the objects we encounter on a daily basis are composed of polymers. These polymers may be synthetic, such as the plastic in disposable bags, or natural, like glycogen in the liver. Recent developments in biotechnology have used synthetic polymers in drug delivery, contact lenses, and even organ transplants. Polyesters, in particular, have been utilized pharmacologically due to their biodegradable properties. Understandably, not all …

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. …

Development Of Highly Efficient Catalyst And Reactions For Organic Synthesis: Monophosphine-Coordinated Palladacycle Complexes For Cross-Coupling Reactions/Polymerizations, Jie Dong

Dissertations, Theses, and Capstone Projects

Transition metal-catalyzed cross-coupling reactions such as Suzuki-Miyaura cross-couplings, are among the most powerful transformations in organic synthesis. They have been extensively used for the synthesis of a wide variety of organic compounds. Recently the Suzuki cross-coupling reaction has been extended to conjugated polymer synthesis, especially the controlled Suzuki cross-coupling polymerization for polymers with the desired length. My research is on developing highly efficient monophosphine-coordinated palladacycle complexes for cross-coupling reactions/polymerizations.

Based on the understanding of transition metal-catalyzed Suzuki cross-coupling reactions including polymerization, my dissertation started with Pd(0)- and Ni(0)-catalyzed borylation reactions of aryl halides and tosylates with bis(pinacolato)diboron to access arylboronates …

Nanogels And Microgels: From Model Colloids To Applications, Recent Developments, And Future Trends, Mattias Karg, Andrij Pich, Thomas Hellweg, Todd Hoare, L. Andrew Lyon, J. J. Crassous, Daisuke Suzuki, Rustam A. Gumerov, Stefanie Schneider, Igor I. Potemkin, Walter Richtering

Engineering Faculty Articles and Research

Nanogels and microgels are soft, deformable, and penetrable objects with an internal gel-like structure that is swollen by the dispersing solvent. Their softness and the potential to respond to external stimuli like temperature, pressure, pH, ionic strength, and different analytes make them interesting as soft model systems in fundamental research as well as for a broad range of applications, in particular in the field of biological applications. Recent tremendous developments in their synthesis open access to systems with complex architectures and compositions allowing for tailoring microgels with specific properties. At the same time state-of-the-art theoretical and simulation approaches offer deeper …

Method Development To Quantify The Reinforcing Properties Of Silica Fillers, Hamid Reza Givehchi

Electronic Theses & Dissertations

Polysiloxane polymers are widely used as a high-temperature resistant materials with the ability to maintain flexibility at extremely low temperatures. Unfortunately, polysiloxane elastomers generally exhibit low strength and poor mechanical properties and have no practical use unless they are reinforced. These elastomers can be mechanically improved through the use of reinforcing silica-based fillers. It is known that silanol groups on the surface of silica filler particles can interact with the polysiloxane backbone. Interactions of silanol groups on the fillers’ surfaces with the polysiloxane backbone through hydrogen bonding may hinder the mobility of the polymer chain and can improve thermal, physical, …