Polymer Chemistry Commons^™

Investigation Of Glassy State Molecular Motions In Thermoset Polymers, Jianwei Tu

Dissertations

This dissertation presents the investigation of the glassy state molecular motions in isomeric thermoset epoxies by means of solid-state deuterium (²H) NMR spectroscopy technique. The network structure of crosslinked epoxies was altered through monomer isomerism; specifically, diglycidyl ether of bisphenol A (DGEBA) was cured with isomeric amine curatives, i.e., the meta-substituted diaminodiphenylsulfone (33DDS) and para-substituted diaminodiphenylsulfone (44DDS). The use of structural isomerism provided a path way for altering macroscopic material properties while maintaining identical chemical composition within the crosslinked networks.

The effects of structural isomerism on the glassy state molecular motions were studied using solid-state ²H …

Self-Assembly And Ring-Opening Metathesis Polymerization Of A Bifunctional Carbonate–Stilbene Macrocycle, Yuewen Xu, Weiwei L. Xu, Mark D. Smith, Linda S. Shimizu

Faculty Publications

No abstract provided.

Impact Of Nanostructure On Polymer-Based Nonvolatile Memory Devices, Seung Hyun Sung

Open Access Theses

Memory functionality is essential for many high-end electronic applications (e.g. , smart phones, personal computers). Particularly, organic nonvolatile memory devices based on polymer ferroelectric materials are a promising approach toward the development of low-cost memory due to the ease of processing and flexibility associated with the device. Here, we will focus on a memory device with a two-component active layer and a diode structure. This ferroelectric diode (FeD) has a nanostructured active layer, composed of ferroelectric and semiconducting polymers, and it can provide easy access to high-performance polymer-based memory devices. In order to create these nanostructured active layers, we …

Supramolecular Biopolymeric Composite Materials: Green Synthesis, Characterization And Applications, Tamutsiwa Moven Mututuvari

Dissertations (1934 -)

Macrocycles, such as crown ethers (CRs) and resorcinarenes (RESs), exhibit selective complexation of heavy metal ions and organic pollutants respectively. Consequently, they have been investigated for their suitability in adsorbing these aqueous pollutants. However, they are difficult to handle and recycle for reuse because, by themselves, they can only be fabricated in powder form. To alleviate this challenge, we developed a method to encapsulate these macrocycles into film-forming polysaccharides--cellulose (CEL) and chitosan (CS). This was achieved by using a green and recyclable solvent, an ionic liquid, to dissolve both macrocycles and polysaccharides and regenerate corresponding composites in water. Resultant composites …

Study Of Polyaniline For Use In An Organic Field Effect Transistor, Thomas Martin Sprinkle

Chemistry & Biochemistry Theses & Dissertations

Polyaniline's emeraldine base form was synthesized via chemical polymerization in HCl acidic media utilizing ammonium persulfate as the oxidant. Synthesis was done at room temperature and -30 'C and characterized for differences by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Methanol soxhlet extraction was done to increase number average molecular weight from 77,400 to 81,000 and decrease the poly dispersity index from 3.82 to 2.14. Films were cast using N, N'- Dimethylpropyleneurea and N-Methylpyrrolidone and showed poor mechanical properties upon acidic doping.

Cyclic voltammetry was done with HC1 as the acidic media and an ITO coated slide as the …

Resin-Supported Arylstannanes As Precursors For Radiolabeling With Iodine: Benzaldehydes, Benzoic Acids, Benzamides, And Nhs Esters, Mustafa Janabi, Catherine M. Pollock, Ann-Marie Chacko, Duncan H. Hunter

Chemistry Publications

A highly cross-linked polystyrene resin bearing a reactive chlorostannane moiety 1 has been used to generate a variety of arylstannane radiopharmaceutical precursors for no-carrier-added radioiodination. The resins were characterized for their solvent compatibility and sensitivity to acid cleavage. Resin-supported arylstannanes synthesized via their aryl lithium analogues include 3- and 4-stannylbenzaldehydes, 3- and 4-stannylbenzoic acids, and 3- and 4-N-succinimidyl benzoates. A three-step route to the resin-supported stannylbenzoic acids 12a/b was developed through resin-supported benzaldehydes 11a/b. The aldehyde to acid conversion efficiency is >90%, and acid loading capacities of 0.66–0.94 mmol/g were obtained. Resin-supported N-succinimidyl benzoates 16a/b …

Synthesis And Applications Of Mutimodal Hybrid Albumin Nanoparticles For Chemotherapeutic Drug Delivery And Phototherml Therapy Platforms, Donna V. Peralta

LSU New Orleans Theses and Dissertations

Progress has been made in using human serum albumin nanoparticles (HSAPs) as carrier systems for targeted treatment of cancer. Human serum albumin (HSA), the most abundant human blood protein, can form HSAPs via a desolvation and crosslinking method, with the size of the HSAPs having crucial importance for drug loading and in vivo performance. Gold nanoparticles have also gained medicinal attention due to their ability to absorb near-infrared (NIR) light. These relatively non-toxic particles offer combinational therapy via imaging and photothermal therapy (PPTT) capabilities.

A desolvation and crosslinking approach was employed to encapsulate gold nanoparticles (AuNPs), hollow gold nanoshells (AuNSs), …

Surgical Adhesive From Mussel Mimetic Polymer, Jenna Desousa, Cori Jenkins, Jonathan Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Injuries involving damaged tissues are currently repaired through an invasive technique involving the use of screws, plates and sutures as support, which can damage these tissues. The biomedical field currently lacks an adhesive that can replace harmful implants. A surgical adhesive can provide a quick and easy alternative, which will minimize the risk of damaging healthy tissue in surgery. Inspiration for such materials can be found by looking at marine mussels as they are able to stick to nearly any surface, even in wet environments. Marine mussels affix themselves to different surfaces using adhesive plaques consisting of various proteins. Polymer …

Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash

Graduate Theses and Dissertations

A new microfluidic pumping and stirring technique was demonstrated for lab-on-a-chip applications. Microfluidics was accomplished via redox-MHD, which takes advantage of a body force (F_B) that is generated when there is a net movement of ions in solution (j) in the presence of a perpendicular magnetic field (B), according to the equation F_B = j×B. In this work the movement of ions in solution was generated using electrodes modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) rather than a redox species in solution, which can interfere with analyte detection and with biological species. …

Poly (N-Isopropylacrylamide) Microgel-Based Thin Film Actuators For Humidity Sensing, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this submission we fabricated a humidity-responsive polymer-based actuator by layering negatively charged poly(N-isopropylacrylamide)-co-acrylic acid microgels and positively charged poly(diallyldimethyl ammonium chloride) on top of a flexible plastic substrate. We show that the extent of the actuation (bending) was dependent on the atmospheric humidity. This property was used to detect atmospheric humidity by hanging weights from the actuator, which were rested on the pan of a top loading balance. This was done in such a way that the amount of the mass resting on the balance depended on the extent of actuator bending, which could then be related to humidity. …

Light Switchable Optical Materials From Azobenzene Crosslinked Poly (N-Isopropylacrylamide)-Based Microgels, Qiang Matthew Zhang, Xue Li, Molla R. Islam, Menglian Wei, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

4,4′-Di(acrylamido)-azobenzene was used as a crosslinker in poly(N-isopropylacrylamide)-based microgels. The microgels were subsequently used to fabricate microgel-based optical materials (etalons), which exhibited optical properties that were switchable upon exposure to UV irradiation. We also show that the extent of the response depended on the UV exposure time. These materials could find applications for controlled/triggered drug delivery, as well as in various optical applications.

Correlating Molecular Architecture Of A Radical Polymer Based Copolymer With Its Electrical Transport Properties, Holly Chan

Open Access Theses

The design and synthesis of electrically-conductive macromolecules can lead to significant improvements in the performance of polymer-based energy conversion devices (e.g., thermoelectric devices). For these organic electronic devices, conjugated polymers have dominated the area of conductive polymers; however, these materials are usually synthesized using conditions that lead to poorly-defined polymers. Furthermore, in these increasingly-standard polymers, the charge transport ability of the polymer thin films is largely affected by the degree of crystallinity, which is a difficult property to control in a reproducible fashion. Therefore, we seek to explore a new class of amorphous, non-conjugated polymers containing a stable radical …

A Novel Label-Free Colorimetric Assay For Dna Concentration In Solution, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Optical devices were fabricated by sandwiching a “monolithic” poly(N-isopropylacrylamide-co-N-(3-aminopropyl) methacrylamide hydrochloride) (pNIPAm-co-APMAH) microgel layer between two semitransparent Au layers. These devices, referred to as etalons, exhibit characteristic multipeak reflectance spectra, and the position of the peaks in the spectra primarily depends on the distance between the Au surfaces mediated by the microgel layer thickness. Here, we show that the positively charged microgel layer can collapse in the presence of negatively charged single stranded DNA (ssDNA) due to ssDNA induced microgel crosslinking. The collapse results in a change in the etalon's optical properties, which can be used to detect target DNA …

Development And Implementation Of Dispersion Phase Diagrams (Dpds) For Four Different Hydrophobically Modified Ethoxylated Urethane (Heur) Based Acrylic Paint Systems, Tyler J. Bell

Master's Theses

Latex polymers serve as binders in a wide range of architectural paints and coatings. A latex is an aqueous colloidal dispersion of polymer particles that when dried above the polymer’s film formation temperature coalesces into a dry polymer film (Dragnevski, Routh, Murray, & Donald, 2010). The other main components of paint include associative thickeners, surfactants, pigments and fillers with the thickener being the primary area of focus for this study.

The relatively simple system of latex, associative thickener and surfactant has been studied extensively. These studies have shown the mechanism of thickening for the associative thickener, and surfactant effects on …

An Investigation Of Poly(N-Isopropylacrylamide) For Applications With Microfluidic Paper-Based Analytical Devices, Haydn Thomas Mitchell

Master's Theses

N,N′-methylenebisacrylamide-crosslinked poly(N-isopropylacrylamide), also known as P(NIPAM), was developed as a fluid delivery system for use with microfluidic paper-based analytical devices (microPADs). MicroPADs are postage-stamp-sized devices made out of paper that can be used as platforms for low-cost, simple-to-use point-of-care diagnostic assays. P(NIPAM) is a thermally responsive polymer that absorbs aqueous solutions at room temperature and will expel the solutions to microPADs when heated. The fluid delivery characteristics of P(NIPAM) were assessed, and P(NIPAM) was able to deliver multiple solutions to microPADs in specific sequences or simultaneously in a laminar-flow configuration. P(NIPAM) was then shown to be suitable …

Improving Hybrid Solar Cells: Overcoming Charge Extraction Issues In Bulk Mixtures Of Polythiophenes And Zinc Oxide Nanostructures, Grant T. Olson

Master's Theses

Organic photovoltaics (OPVs) have received a great deal of focus in recent years as a possible alternative to expensive silicon based solar technology. Current challenges for organic photovoltaics are centered around improving their lifetimes and increasing their power conversion efficiencies. One approach to improving the lifetime of such devices has been the inclusion of inorganic metal oxide layers, but interaction between the metal oxides and common conjugated polymers is not favorable. Here we present two methods by which the interactions between polythiophenes and nanostructured ZnO can be made to be more favorable. Using the first method, direct side on attachment …

Poly (N-Isopropylacrylamide) Microgel-Based Optical Devices For Sensing And Biosensing, Molla R. Islam, Andrews Ahiabu, Xue Li, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Responsive polymer-based materials have found numerous applications due to their ease of synthesis and the variety of stimuli that they can be made responsive to. In this review, we highlight the group’s efforts utilizing thermoresponsive poly (N-isopropylacrylamide) (pNIPAm) microgel-based optical devices for various sensing and biosensing applications.

Synthesis And Characterization Of Some Thallium Salt Complexes, Levi Dopierala

Masters Theses & Specialist Projects

Research into conductive organic and organometallic polymers began in 1977 when Heeger, Macdiarmid, and Shirakawa first doped polyacteylene with Iodine. They found that this doping granted the polymer metallic properties increasing conductivity by 11 orders of magnitude.[1] Unfortunately, polyacteylene is highly air-sensitive making it difficult to work with and limiting its applications. Therefore, current research is focused on synthesizing new organic and organometallic conductive polymers. The drive to discover these new polymers stems from their application flexibility and their low production cost.

Reported here is the synthesis of novel organometallic polymer precursors. Lead by Dr. Chad Snyder a library of …

Porphyrin Cross-Linkers For Generating Soluble Molecularly Imprinted Polymers From Polyethyleneimine, Mohammed R. Elshaer

Seton Hall University Dissertations and Theses (ETDs)

Molecular recognition is vital to many biochemical processes and is at the heart of promising bio-medically related technologies. Molecular imprinting has a long-standing history as a successful method for mimicking the molecular recognition phenomena exhibited by nature, whereby artificial receptors are prepared for a given target molecule based on synthetic polymers. The molecularly imprinted polymer (MIP) contains a three dimensional network with a memorized cavity specific to the shape and functionality of the templated target molecule. The utility of traditional MIPs has been limited due to an inherent lack of solubility. We have worked toward developing a system that allows …

Effects Of Varying The Cure Profiles Of An Epoxy-Amine System, Patrick W. Hollingsworth

Honors Theses

The cure of an epoxy prepolymer with an amine hardener induces stress in thermosetting systems. The extent of residual stresses in the cured epoxy-amine thermosets are dependent on several factors; one of which is the cure profile utilized. The effect of cure profile on cure induced stresses of an epoxy-amine thermoset was examined in the current study. A difunctional epoxide based on diglycidyl ether of bisphenol-A (DGEBA) and a tetrafunctional amine curative were used to conduct this study. Two cure profiles were selected to prepare samples of varying degrees of stress in the cured thermosets. The first was constant heating …