Chemistry Commons^™

Transesterification Of Poly(Ethyl Glyoxylate): A Route To Structurally Diverse Polyglyoxylates, Rebecca E. Yardley, Amir Rabiee Kenaree, Xiaoli Liang, Elizabeth R. Gillies

Chemistry Publications

Polyglyoxylates are a class of self-immolative polymers that depolymerize in solution and the solid state. The glyoxylic acid degradation product is a metabolite in the glyoxylate cycle and can also be processed in the liver in humans, making polyglyoxylates attractive for applications in the environment and in medicine. Although expanding the scope of available polyglyoxylates would enable new properties and applications, highly pure glyoxylate monomers are required for polymerization, and this level of purity is difficult to achieve for many potential monomers. To address this challenge, we report here the 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD)-catalyzed post-polymerization transesterification of poly(ethyl glyoxylate) (PEtG) as a …

Thermoresponsive Self-Immolative Polyglyoxylamides., Amir Rabiee Kenaree, Quinton E. A. Sirianni, Kyle Classen, Elizabeth R. Gillies

Chemistry Publications

Thermoresponsive polymers with lower critical solution temperatures (LCSTs) are of significant interest for a wide range of applications from sensors to drug delivery vehicles. However, the most widely investigated LCST polymers have nondegradable backbones, limiting their applications

Phosphonium Versus Ammonium Compact Polyelectrolyte Complex Networks With Alginate-Comparing Their Properties And Cargo Encapsulation., Tristan D. Harrison, Alexandre J. Salmon, John R. De Bruyn, Paul J. Ragogna, Elizabeth R. Gillies

Chemistry Publications

Phosphonium and ammonium polymers can be combined with polyanions to form polyelectrolyte complex (PEC) networks, with potential application in self-healing materials and drug delivery vehicles. While various structures and compositions have been explored, to the best of our knowledge, analogous ammonium and phosphonium networks have not been directly compared to evaluate the effects of phosphorus versus nitrogen cations on the network properties. In this study, we prepared PECs from sodium alginate and poly[triethyl(4-vinylbenzyl)phosphonium chloride], poly[triethyl(4-vinylbenzyl)ammonium chloride], poly[tri(

Discriminating Azo Dyes: Conjugated Polymers, The Inner Filter Effect, And Array Sensors, Erin Crater

Honors Theses

Azo dyes are abundant pollutants that contaminate water supplies and threaten humans, biota, and ecosystem health. Their detection and discrimination are an incredible challenge due to the structural, chemical, and optical similarities between dyes, the complexity of the wastewater environment in which they are found, and their low environmental concentrations. In this work, the inner filter effect (IFE), combined with conjugated polymer array-based sensing, is utilized for the quantitative profiling of these pollutants. The array was constructed using three fluorescent, anionic conjugated polyelectrolytes whose varying spectroscopic properties led to distinct IFE patterns in the presence of the dyes. The unique …

Polymers For Extrusion‐Based 3d Printing Of Pharmaceuticals: A Holistic Materials–Process Perspective, Mohammad A. Azad, Deborah Olawuni, Georgia Kimbell, Abu Zayed Badruddoza, Md. Shahadat Hossain, Tasnim Sultana

Publications and Research

Three dimensional (3D) printing as an advanced manufacturing technology is progressing to be established in the pharmaceutical industry to overcome the traditional manufacturing regime of ʹone size fits for allʹ. Using 3D printing, it is possible to design and develop complex dosage forms that can be suitable for tuning drug release. Polymers are the key materials that are necessary for 3D printing. Among all 3D printing processes, extrusion‐based (both fused deposition modeling (FDM) and pressure‐assisted microsyringe (PAM)) 3D printing is well researched for pharmaceutical manufacturing. It is important to understand which polymers are suitable for extrusion‐based 3D printing of pharmaceuticals …

Preparation And Characterization Of Light Sensitive Tetrafluoro-Lambda6-Sulfanyl-Containing Polymers, Kelly A. Bonetti

Legacy Theses & Dissertations (2009 - 2024)

The addition of the pentafluorosulfanyl (SF5) group to an unsaturated organic starting material became popular in the 1960s, following the widening commercial availability of SF5Cl and SF5Br. However, the free radical reaction conditions required limited a broader appreciation of this critical advance. Moreover, while important thermal, photochemical and free-radical initiated addition reactions were reported, the unique photosensitivity of these compounds was not well understood. In 2012, a scalable synthetic route was developed affording aryl-SF5-containing derivatives via a novel aryl-SF4Cl intermediate. As a result, a heightened interest in hypervalent fluorinated sulfur containing materials was renewed. In 2014, the visible light addition …

Synthesis Of Bio-Based Polymer Products, Joshua Sukie

Williams Honors College, Honors Research Projects

The project covers the synthesis of two bio-based polymers. One aspect of the research investigates the synthesis of materials for use in vegetable oil-based UV-curable coating, and the subsequent polymerization of the materials into a coating film. The second aspect of the research follows the synthesis of a functionalized cellulose material for use as a reinforcer in a vegetable oil-based composite. Both products are subsequently analyzed by various methods.

Polyacrylamide In Glycerol Solutions From An Atomistic Perspective Of The Energetics, Structure, And Dynamics, Scott D. Hopkins, Gideon K. Gogovi, Eric Weisel, Robert A. Handler, Estela Blaisten-Barojas

VMASC Publications

All-atom molecular dynamics is used to investigate the structural, energetic, and dynamical properties of polyacrylamide (PAM) oligomers of different lengths solvated in pure glycerol, a 90:10 glycerol–water mixture, and pure water. We predict that the oligomers’ globular structure is obtained only when the modeling strategy considers the solvent as a continuous background. Meanwhile, for all-atom modeled solvents, the glycerol solutions display a strong tendency of trapping the oligomers in instantaneous elongated random coiled structures that remain locked-in over tens of nanoseconds. In pure water, the oligomers acquire considerably shorter random coiled structures of increased flexibility. The all-atom force field, generalized …

Intra- And Intermolecular Self-Assembly Of A 20-Nm-Wide Supramolecular Hexagonal Grid, Zhe Zhang, Yiming Li, Bo Song, Yuan Zhang, Xin Jiang, Ming Wang, Ryan Tumbleson, Changlin Liu, Pingshan Wang, Xin-Qi Hao, Tomas Rojas, Anh T. Ngo, Jonathan L. Sessler, George R. Newkome, Saw Wai Hla, Xiaopeng Li

Physics Faculty Publications

For the past three decades, the coordination-driven self-assembly of three-dimensional structures has undergone rapid progress; however, parallel efforts to create large discrete two-dimensional architectures—as opposed to polymers—have met with limited success. The synthesis of metallo-supramolecular systems with well-defined shapes and sizes in the range of 10–100 nm remains challenging. Here we report the construction of a series of giant supramolecular hexagonal grids, with diameters on the order of 20 nm and molecular weights greater than 65 kDa, through a combination of intra- and intermolecular metal-mediated self-assembly steps. The hexagonal intermediates and the resulting self-assembled grid architectures were imaged at submolecular …

Macromolecular Engineering Of Biomass Polymers And Stimuli-Responsive Materials Towards Enhanced Thermomechanical Properties, Meghan E. Lamm

Theses and Dissertations

Commodity polymers are used in every aspect of daily life, and most of these polymeric materials are synthesized using petroleum-derived sources. There are direct environmental consequences to this petroleum dependence including greenhouse gas emissions and climate change. Biomass-based polymers show promise for the mitigation on negative environmental impact, in comparison with petroleum-derived counterparts. However, some biopolymers suffer from low chain entanglement due to bulky or long side chain structures, resulting in poor mechanical properties. In this dissertation work, macromolecular engineering is used to design biomass-derived polymers featuring a variety of structures and functionalities. Additionally, biopolymer properties (including thermomechanical enhancement) and …

Erratum: "Imaging The Three‐Dimensional Orientation And Rotational Mobility Of Fluorescent Emitters Using The Tri‐Spot Point Spread Function", Oumeng Zhang, Jin Lu, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

In the original paper, a calibration error exists in the image-formation model used to analyze experimental images taken by our microscope, causing a bias in the orientation measurements in Figs. 2 and 3. The updated measurements are shown in Fig. E1. We have also updated the supplementary material for the original article to discuss the revised PSF model and estimation algorithms (supplementary material 2) and show the revised model and measurements (Figs. S1, S3, S7, S8, and S10–S13).

Iron Detection And Remediation With A Functionalized Porous Polymer Applied To Environmental Water Samples, Sumin Lee, Adam Uliana, Mercedes K. Taylor, Gary J. Long, Fernande Grandjean, For Full List Of Authors, See Publisher's Website.

Chemistry Faculty Research & Creative Works

Iron is one of the most abundant elements in the environment and in the human body. As an essential nutrient, iron homeostasis is tightly regulated, and iron dysregulation is implicated in numerous pathologies, including neuro-degenerative diseases, atherosclerosis, and diabetes. Endogenous iron pool concentrations are directly linked to iron ion uptake from environmental sources such as drinking water, providing motivation for developing new technologies for assessing iron(ii) and iron(iii) levels in water. However, conventional methods for measuring aqueous iron pools remain laborious and costly and often require sophisticated equipment and/or additional processing steps to remove the iron ions from the original …

Sustainable Polymers And Antimicrobial Biomaterials From Multicyclic Natural Products, Md Anisur Rahman

Theses and Dissertations

In this dissertation, the development of sustainable polymers and antimicrobial biomaterials from multicyclic natural products is illustrated. In Chapter 1, an overall background and recent development of sustainable polymers from natural product-based renewable biomass, antimicrobial biomaterials, and polymerization methods are introduced. Afterward, the primary research objectives of my doctoral research work are illustrated.

In chapter 2, designing block copolymer architectures toward tough bioplastics from renewable natural rosin was described. One of the most abundant natural biomasses is resin acids, however, most of the polymers derived from resin acids are brittle because of their bulky hydrophenanthrene pendant group. To overcome the …

Nanomaterials For Double-Stranded Rna Delivery, Stuart Lichtenberg

Theses and Dissertations--Plant and Soil Sciences

RNA interference has enormous potential as a potent, specific, and environmentally friendly alternative to small molecule pesticides for crop protection. The use of exogenous double-stranded RNA offers flexibility in targeting and use in crops in which transgenic manipulation is not an option. The combination of RNAi with nanotechnology offers further advantages that are not available with dsRNA alone. In this work, I have evaluated several different combinations of nanomaterials and polymers for use in RNAi-based pest control systems. First, I have characterized the use of chitosan/dsRNA polyplex nanoparticles for gene knockdown using the model nematode Caenorhabditis elegans. Though chitosan/dsRNA …

Synthesis Of N-Heterocyclic Molecules And Their Applicability Towards Ion Sensing: Polymeric Chemosensors, Aikohi M. Ugboya

College of Graduate Studies: Theses & Dissertations

Critical to biological and environmental processes are anions because often times their relative concentration in our body can be an indicator of one’s well-being. Therefore, highly sensitive and cost-efficient methods for ions recognition is necessary for human health. In recent times, polymeric chemosensors have become a vital tool for sensing ions because of its higher sensitivity and good mechanical properties compared to their monomeric counterparts. These sensors are designed to produce a measurable response in the presence of a targeted ion such as an electrochemical or optical signal. The unique structure and the photophysical properties of the 1,2,3-triazole core coupled …

Functionalized Peek Analogues From 2,4- And 3,5- Difluorobenzophenone Derivatives, Hannah Fetters

Browse all Theses and Dissertations

The synthesis of N-heterocycle functionalized benzophenone-type monomers and their incorporation into poly(arylene ether ketone)s were explored. Two benzophenone derivatives, 2,4-difluorobenzophenone and 3,5-difluorobenzophenone, were successfully functionalized with a carbazole group, via a copper-catalyzed C-N coupling reaction. Structural characterization was provided by NMR spectroscopy, GC/MS, and elemental analysis. The monomers were covalently incorporated, at various molar ratios, into poly(arylene ether) systems by copolymerization with 4,4’-difluorodiphenylsulfone (DPS) and 4,4’-dihydroxydiphenyl ether (DPE), as well as 4,4’-difluorotriphenylphosphine oxide (dFTPPO) and DPE, via nucleophilic aromatic substitution (NAS) chemistry. Most polymeric materials synthesized provided sufficient molecular weights to cast durable films, and also possessed good thermal stability …

A Simple And Robust Approach To Reducing Contact Resistance In Organic Transistors, Zachary A. Lamport, Katrina J. Barth, Hyunsu Lee, Eliot Gann, Sebastian Engmann, Hu Chen, Martin Guthold, Iain Mcculloch, John E. Anthony, Lee J. Richter, Dean M. Delongchamp, Oana D. Jurchescu

Chemistry Faculty Publications

Efficient injection of charge carriers from the contacts into the semiconductor layer is crucial for achieving high-performance organic devices. The potential drop necessary to accomplish this process yields a resistance associated with the contacts, namely the contact resistance. A large contact resistance can limit the operation of devices and even lead to inaccuracies in the extraction of the device parameters. Here, we demonstrate a simple and efficient strategy for reducing the contact resistance in organic thin-film transistors by more than an order of magnitude by creating high work function domains at the surface of the injecting electrodes to promote channels …

Influence Of High Aspect Ratio Nanoparticle Filler Addition On Piezoelectric Nanocomposites, Jeremy A. Armas

Master's Theses

Piezoelectric nanogenerators (PNGs) are a new class of energy harvesting materials that show potential as a direct energy source for low powered electronics. Recently, piezoelectric polymers have been utilized for PNG technology due to low toxicity, high flexibility, and facile solution processing which provide manufacturing opportunities such as screen printing. Throughout the last decade, countless projects have focused on how to enhance the energy harvesting capabilities of these PNGs through the incorporation of nanoparticle fillers, which have been reported to enhance the piezoelectric properties of the film either directly through their intrinsic piezoelectric properties or through acting as surfaces for …

Metallo-Polyelectrolytes As A Class Of Ionic Macromolecules For Functional Materials, Tianyu Zhu, Ye Sha, Jing Yan, Parasmani Pageni, Md Anisur Rahman, Yi Yan, Chuanbing Tang

Faculty Publications

The fields of soft polymers and macromolecular sciences have enjoyed a unique combination of metals and organic frameworks in the name of metallopolymers or organometallic polymers. When metallopolymers carry charged groups, they form a class of metal-containing polyelectrolytes or metallo-polyelectrolytes. This review identifies the unique properties and functions of metallo-polyelectrolytes compared with conventional organo-polyelectrolytes, in the hope of shedding light on the formation of functional materials with intriguing applications and potential benefits. It concludes with a critical perspective on the challenges and hurdles for metallo-polyelectrolytes, especially experimental quantitative analysis and theoretical modeling of ionic binding.

Surprising Antibacterial Activity And Selectivity Of Hydrophilic Polyphosphoniums Featuring Sugar And Hydroxy Substituents., Tyler J Cuthbert, Benjamin Hisey, Tristan D Harrison, John F Trant, Elizabeth R Gillies, Paul J Ragogna

Chemistry Publications

There is currently an urgent need for the development of new antibacterial agents to combat the spread of antibiotic-resistant bacteria. We explored the synthesis and antibacterial activities of novel, sugar-functionalized phosphonium polymers. While these compounds exhibited antibacterial activity, we unexpectedly found that the control polymer poly(tris(hydroxypropyl)vinylbenzylphosphonium chloride) showed very high activity against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus and very low haemolytic activity against red blood cells. These results challenge the conventional wisdom in the field that lipophilic alkyl substituents are required for high antibacterial activity and opens prospects for new classes of antibacterial polymers.

Synthesis Of A Silsesquioxane Based Supramolecular Polymer, Rachel Bianculli

Honors Projects

Research toward smart materials, specifically self-healing polymers, is an expanding topic within the materials science field. These materials rely heavily on dynamic crosslinking that is achieved by inducing different degrees of hydrogen bonding, van der Waals forces, etc. This work, demonstrated by research previously done within the Ostrowski research group, shows how coordination bonds of transition metals have been shown to create light activated, self-healing properties. Work done with these light-activated chromium (III) complexes with a poly(butylyene-co-ethylene) backbone have shown how metal—ligand coordination geometries can tune mechanical properties of the polymeric material. However, these materials suffer from being incredibly soft …

Ring Opening Polymerization, Zoua Pa Vang

Celebrating Scholarship and Creativity Day (2018-)

The goal of the research discussed in this paper is to demonstrate that N-heterocyclic carbenes can be bonded to a transition metal center resulting in a complex that is able to effectively catalyze the ring opening polymerization of caprolactone. While N-Heterocyclic carbene ligands have been documented as effective catalysts for the ring opening polymerization (ROP) of lactones and lactides, less is known about the catalytic abilities of these ligands when bound to a labile metal center. This article focuses on examining the synthesis and reactivity of different transition metal complexes containing tin, zinc, aluminium and titanium metal centers. In addition …

Preparation Of Polymeric Materials From Bio-Renewable Sources, Jason Douglas Smith

Theses and Dissertations

The focus of this project was to develop methodologies for the preparation of novel polymeric materials from bio-renewable sources. In order to complete this task we needed (a) unfettered access to bio-based materials and ways to convert them to value needed chemicals, as well as, (b) reaction protocols that would allow greater diversity during the synthesis of polymeric compounds so as to affect the properties of these materials.

Our research group has a background in converting plant-based materials like cellulose into value added chemicals employing catalytic reactions. The polymerization of these monomers was then conducted utilizing the Baylis-Hillman reaction. The …

Synthesis And Characterization Of Mpims : Metallopolymers Of Intrinsic Microporosity, Kelly Walter

Legacy Theses & Dissertations (2009 - 2024)

Polymers of intrinsic microporosity (PIMs) are class of polymers known for high surface areas arising from their contorted and rigid backbone structures. While high surface area compounds are applicable in many fields, simultaneous solubility and conductivity in PIMs is still lacking. In general, the monomeric units that form the backbone, necessary to yield inefficient polymer strand packing and contortion, also break conjugation in the along the polymer backbone and therefore limit conductivity. It has been previously noted that extended conjugation and the addition of metal atoms (along the backbone) increases conductivity. We therefore sought to use a strategy whereby the …

Significance Of A Non-Thermal Plasma Treatment On Ldpe Biodegradation With Pseudomonas Aeruginosa, Laurence Scally, Miroslav Gulan, Lars Weigang, Vladimir Milosavljević, Patrick J. Cullen

Articles

The use of plastics has spanned across almost all aspects of day to day life. Although their uses are invaluable, they contribute to the generation of a lot of waste products that end up in the environment and end up polluting natural habitats such as forests and the ocean. By treating low-density polyethylene (LDPE) samples with non-thermal plasma in ambient air and with an addition of ≈4% CO2, the biodegradation of the samples can be increased due to an increase in oxidative species causing better cell adhesion and acceptance on the polymer sample surface. It was, however, found that the …

Characterization Of Coacervate Systems Using Redox Sensitive Dyes, Caleb Kaiser

All Master's Theses

Coacervates are systems that spontaneously form when two oppositely charged polyelectrolytes are mixed in a concentrated salt solution. When coacervates form, a biphasic equilibrium occurs in the sample with two phases present in the solution. The two phases are described as the dense phase and the lean phase, named after the amount of polyelectrolyte material in each phase. Coacervates have been topics of interest to researchers in a variety of fields including biomedical applications, drug delivery devices, and more. This thesis worked towards the characterization of coacervate systems on the molecular level by investigating the interaction of the polyelectrolytes and …

Synthesis Of Small-Molecule Fluorescent Probe And Polymers For Bioapplication: Bioimaging And Enzyme Stabilization, Yanmei Xu

Theses and Dissertations

In chapter one, we designed, synthesized and characterized two cysteine sensors CCPAP and CCPAN, with improved water solubility, cell penetration ability, and potential targeting selectivity. Two types of positive charged groups, i.e. triphenylphosphonium and pyridinium were introduced respectively to the frame structure CCP by coupling carboxylic acid with amine to improve the cell permeability and cysteine selectivity. ESI-MS, NMR and IR were employed to characterize the molecular structures of the two novel probes. These probes have better water solubility than the parent molecule DCP, and better cell penetration capability than CEP, which could further distinguish the cysteine concentration differences in …

Sustainable Soybean Oil And Lignin Derived Monomers And Polymers For Potential Use In Polymeric Materials, Ryan Miskin

Theses and Dissertations

In this thesis project, high oleic soybean oil and lignin derived monomers and polymers are investigated. The properties of these monomers and polymers are characterized and discussed.

Chapter 1 details the potential impact of bio-based resources, monomers, and polymers on the environment. An introduction on polymerization techniques is given, and the overall objectives of my research are discussed.

In Chapter 2, attempts are made at modifying a soybean oil derived thermoplastic polymer into a vitrimer. The synthesis of thermoplastics is reviewed and the vitrimer trials outlined. Different scenarios that arose are examined and discussed.

Chapter 3 outlines the preparation of …

Nitrogen Rich Porous Organic Frameworks: Proton Conduction Behavior Of 3d Benzimidazole And Azo-Linked Polymers, Michael J. Anhorn

Theses and Dissertations

Nitrogen-rich porous organic frameworks show great promise for use as acid-doped proton conducting membranes, due to their high porosity, excellent chemical and thermal stability, ease of synthesis, and high nitrogen content. Aided by very high surface area and pore volume, the material has the ability to adsorb high amounts of H₃PO₄ into its network, which creates a proton rich environment, capable of facile proton conduction. The morphology and chemical environment, doping behavior, and proton conduction of these materials were investigated. With such high acid-doping, ex-situ studies revealed that under anhydrous conditions, PA@BILP-16 (AC) produced a proton conductivity …

Preferential Binding Effects On Protein Structure And Dynamics Revealed By Coarse-Grained Monte Carlo Simulation, Ras B. Pandey, D.L. Jacobs, Barry L. Farmer

Faculty Publications

The effect of preferential binding of solute molecules within an aqueous solution on the structure and dynamics of the histone H3.1 protein is examined by a coarse-grained Monte Carlo simulation. The knowledge-based residue-residue and hydropathy-index-based residue-solvent interactions are used as input to analyze a number of local and global physical quantities as a function of the residue-solvent interaction strength (f). Results from simulations that treat the aqueous solution as a homogeneous effective solvent medium are compared to when positional fluctuations of the solute molecules are explicitly considered. While the radius of gyration (R_g) of the …