Physical Sciences and Mathematics Commons^™

Synthesis And Characterization Of Manganese Pyridazyl Complexes, Sana Shah

Masters Theses & Specialist Projects

Heterocyclic’s and their fused-ring derivatives have been of interest for their use in electronic materials due to their ease of production, synthetic versatility, and low cost compared to traditional inorganic materials like silicon. Pyridazines have been found to be useful in catalysis gas storage, polymeric sensors and biological mimetics. When a transition-metal is fused into a synthesized pyridazine, unique properties such as conductivity and optics are allowed. In this work, synthesized pyridazine complexes will be analyzed by mass spectroscopy, elemental analysis, nuclear magnetic resonance, imaging, x-ray crystallography, and infrared spectroscopy. We are interested in synthesizing organometallic pyridazines and manganese pyridazyl …

Obstacles And Solutions To Studying Functional Adhesives Using Vibrational Sum-Frequency Generation Spectroscopy, Angela Renee Andersen

Theses and Dissertations

Important aspects of adhesion occur at interfaces, including structures that may be different from those in the bulk materials. However, probing the orientation of molecules in functional adhesives poses a significant challenge because adhesive molecules are always located at a buried interface. The limited penetration depth of surface-specific analysis prohibits the study of buried interfaces using those techniques. The large quantity of bulk molecules relative to the adhesive molecules interacting at the interface results in the bulk signal swamping out adhesive signal in bulk analysis techniques. An interface-specific technique is required to study functional adhesives. One such technique that has …

Enhancing The Performance Of Organic Thin Film Transistors By Cross-Linking The Organic Gate Dielectric, Soheila Naderi Gohar

Electronic Thesis and Dissertation Repository

Amongst various surface modification techniques, hyperthermal hydrogen induced cross-linking (HHIC) has been used to modify the surface of polymeric samples. In this novel and innovative technique neutral hydrogen projectiles with appropriate kinetic energy are produced to generate carbon radicals on the impacted surface through the collision-induced C-H bond breaking. Subsequently, this phenomenon results in cross-linking hydrocarbon chains in the treated polymeric samples.

Verifying the validity of cross-linking process through experiments is the target of first part of presented dissertation. Spin-coated poly(methyl methacrylate) (PMMA) films on silicon wafer were exposed to hydrogen projectiles for different durations, while the other conditions related …

Highly Piezoelectric Biocompatible And Soft Composite Fibers, J. Morvan, E. Buyuktanir, John L. West, Antal Jakli

Antal Jakli

We report the fabrication of highly piezoelectric biocompatible soft fibers containing barium titanate ferroelectric ceramic particles dispersed in electrospun poly lactic acid (PLA). These fibers form mats that have two orders of magnitude larger piezoelectric constant per weight than single crystal barium titanate films. We propose that the observed apparent piezoelectricity results from the electrospinning induced polar alignment of the ferroelectric particles that pole the fibers similar to ferroelectret polymer foams that are poled by corona discharge. Due to the biocompatibility of PLA that encases the ferroelectric particles, these mats can be used in biological applications such as bio-sensors, artificial …

Large Flow Birefringence Of Nematogenic Bent-Core Liquid Crystals, C. Bailey, Katalin Fodor-Csorba, Rafael Verduzco, Jim T. Gleeson, Samuel N. Sprunt, Antal Jakli

Antal Jakli

We have found that bent-core liquid crystalline materials show exceptionally large intrinsic flow birefringence in their isotropic liquid phase. This effect is more than 100 times larger than typical values measured for low molecular weight liquid crystals. The specific flow birefringence (i.e., normalized by the flow viscosity) is an order of magnitude larger than in both side-chain polymeric as well as low molecular weight liquid crystals. We propose that this large enhancement for bent-core compounds may be attributed to nanoscale smecticlike clusters that persist above the nematic-isotropic transition temperature, and shear align under shear flow; however, this mechanism has not …

Compendium Of Polymer Terminology And Nomenclature: Iupac Recommendations, 2008 (Book Review), Jeffrey H. Glans

Jeffrey H. Glans

Book review by Jeffrey Glans. Polymer Division, International Union of Pure and Applied Chemistry. Compendium of Polymer Terminology and Nomenclature: IUPAC Recommendations, 2008. Royal Society of Chemistry, 2009.

Length Scales Of Interactions In Magnetic, Dielectric, And Mechanical Nanocomposites, Ralph Skomski, Balamurugan Balamurugan, Eva Schubert, Axel Enders, David J. Sellmyer

Axel Enders

It is investigated how figures of merits of nanocomposites are affected by structural and interaction length scales, Aside from macroscopic effects without characteristic lengths scales and atomic-scale quantum-mechanical interactions there are nanoscale interactions that reflect a competition between different energy contributions. We consider three systems, namely dielectric media, carbon-black reinforced rubbers and magnetic composites. In all cases, it is relatively easy to determine effective materials constants, which do not involve specific length scales. Nucleation and breakdown phenomena tend to occur on a nanoscale and yield a logarithmic dependence of figures of merit on the macroscopic system size. Essential system-specific differences …

The Torsion Angle Of Random Walks, Mu He

Masters Theses & Specialist Projects

In this thesis, we study the expected mean of the torsion angle of an n-step
equilateral random walk in 3D. We consider the random walk is generated within a confining sphere or without a confining sphere: given three consecutive vectors ^→e₁ , ^→e₂ , and ^→e₃ of the random walk then the vectors ^→e₁ and ^→e₂ define a plane and the vectors ^→e₂ and ^→e₃ define a second plane. The angle between the two planes is called the torsion angle of the three vectors. Algorithms are …

Measurements Of The Temperature Dependence Of Radiation Induced Conductivity In Polymeric Dielectrics, Jodie Corbridge Gillespie

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Radiation Induced Conductivity (RIC) is the change in conductivity of a material due to bombardment from incident high energy radiation. This study is to determine the effect of RIC and RIC's temperature dependence in polymeric dielectrics, specifically Kapton HN, Kapton E, PTFE Teflon, Tefzel, and Low Density Polyethylene (LDPE). Interest in these materials arises from applications for use in future spacecraft, specifically the James Webb Space Telescope (JWST).

One major issue in the design of JWST, as in all spacecraft, is the charging and arcing of exposed materials, resulting in fatal damage to the electronics and/or the craft itself. Particles …

6 Ghz Microstrip Patch Antennas With Pedot And Polypyrrole Conducting Polymers, Akhilesh Verma, Bo Weng, Roderick L. Shepherd, Christophe Fumeaux, Van Tan Truong, Gordon G. Wallace, Bevan D. Bates

Gordon Wallace

Two 6 GHz microstrip patch antennas made from conducting polymers with relatively low DC conductivity such as PEDOT (10000 S/m) and PPy (2000 S/m) are presented. The performance of these patch antennas is compared with a similar copper patch antenna. The results indicate that it is possible to obtain reasonable performance albeit with modest radiation efficiencies. The PEDOT antenna achieved a maximum gain of 2.2 dB, while the PPy antenna reached a gain of 3.8 dB, as against 6.0 dB for a corresponding Cu patch antenna The results confirm the potential of polymer materials for microwave antennas and suggest that …

Conducting Polymers With Fibrillar Morphology Synthesized In A Biphasic Ionic Liquid/Water System, J.M. Pringle, Orawan Ngamna, Carol M. Lynam, Gordon G. Wallace, Maria Forsyth, Douglas Macfarlane

Gordon Wallace

The synthesis of poly(pyrrole), poly(terthiophene), and poly(3,4-ethylenedioxythiophene) with unusual fibrillar morphologies has been achieved by chemical polymerization in a biphasic ionic liquid/water system. Use of aqueous gold chloride as the oxidant, with the monomers dissolved in a hydrophobic ionic liquid, allows the polymerization to occur at the ionic liquid/water interface. The resultant conducting polymer fibrils are, on average, 50−100 nm wide and can be thousands of nanometers long. The polymers produced in this ionic liquid system are compared to those synthesized in a biphasic chloroform/water system.

Synthesis, Modeling, And Characterization Of Conducting Polymers, Geoffrey M. Spinks, Lianbin Zhao, Weihua Li, Yanzhe Wu, Dezhi Zhou, Gordon G. Wallace

Gordon Wallace

This paper presents synthesis and characterization of polypyrrole based conducting polymers in terms of electronic and mechanical disciplines. Using the electrochemical polymerization approach, conducting polymer samples with different dimensions (length, width, and thickness) was fabricated. For each sample, both sinusoidal and step excitations were used to study its mechanical and electrical properties. An equivalent electric circuit based on constant phase element (CPE) is proposed to model such responses. Electrochemical impedance spectroscopy (EIS) method was used to identify the relationship between the dimensions of conducting polymers and model elements parameters.

Comparative Displacement Study Of Bilayer Actuators Comprising Of Conducting Polymers, Fabricated From Polypyrrole, Poly(3,4- Ethylenedioxythiophene) Or Poly(3,4-Propylenedioxythiophene), Babita Gaihre, Syed Ashraf, Geoffrey M. Spinks, Peter C. Innis, Gordon G. Wallace

Gordon Wallace

The stress gradient generated due to electrochemical oxidation/reduction of a conducting polymer in a bilayer actuator causes a bending movement. Here we report a comparative study of the displacement of bilayer actuators prepared using different conducting polymers. The effects of conducting polymers obtained from electrochemical or chemical synthesis route: different polymers (polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) PEDOT and poly(3,3-dihexyl-3-4-dihydro-2H-thieno[3,4b][1,4]-dioxepine [PProDOT(Hx) 2]); and different electrolytes (0.1 M lithium trifluromethanesulfonate/propylenecarbonate (LiTFSI/PC) and 1-ethyl-3-methyl imidazolium trifluromethanesulfonate (EMITFSI)) on the displacement amplitude and displacement patterns of these actuators were investigated and compared. The results indicate that the bilayer actuator consisting of an electrochemically synthesized conducting polymer …

Photoelectrochemical Cells Based On Inherently Conducting Polymers, Gordon G. Wallace, Chee O. Too, David L. Officer, Paul C Dastoor

Gordon Wallace

This review of photoelectrochemical cells (PECs) based on inherently conducting polymers (ICPs) deals with the mechanisms of operation and the various factors that influence the overall efficiency of PECs. The factors addressed include ICP composition and oxidation state, the use of nanostructured surfaces and interfaces, and the PEC electrolyte and redox mediator.

Design, Synthesis And Characterization Of Chain-End Functionalized Glyco-Polymer For Efficient Proteomic Analysis, Satya Nandana Narla

ETD Archive

No abstract provided.

Optical Switching Of Protein Interactions On Photosensitive-Electroactive Polymers Measured By Atomic Force Microscopy, Amy Gelmi, Michele Zanoni, Michael J. Higgins, Sanjeev Gambhir, David L. Officer, Dermot Diamond, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

The ability to switch the physico-chemical properties of conducting polymers opens up new possibilities for a range of applications. Appropriately functionalised materials can provide routes to multi-modal switching, for example, in response to light and/or electrochemical stimuli. This capability is important in the field of bionics wherein remote and temporal control of the properties of materials is becoming attractive. The ability to actuate a film via photonic stimuli is particularly interesting as it facilitates the modulation of interactions between host binding sites and potential guest molecules. In this work, we studied two different poly-terthiophenes: one was functionalised with a spiropyran …

Microstructures Of Conducting Polymers: Patterning And Actuation Study, Babita Gaihre, Bo Weng, Syed A. Ashraf, Geoffrey M. Spinks, Peter C. Innis, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

The conducting polymers exhibit electrochemically driven expansion and shrinkage due to ingress and egress of dopant ions in response to potential applied. In this paper, we report on patterning of microdots and microsquares of polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,3-dihexyl-3-4-dihydro-2H-thieno[3,4b][1,4]-dioxepine PProDOT(Hx) 2 and their behaviour under voltage change. Stainless steel mesh was used to deposit microdots and inkjet-printed cellulose girds were used to deposit microsqures of the conducting polymers on the ITO surface. It was found that PPy showed distinct actuation in the z direction while colour change was prominent in the case of PEDOT and PProDOT(Hx)2.

Colour Tunable Electrochromic Devices Based On Pprodot-(Hx)2 And Pprodot-(Ethx)2 Polymers, Bo Weng, Syed Ashraf, Peter C. Innis, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

The most commonly used method to tune the colour transition states of an ECD is to modify the chemical structure of the electrochromic polymers to achieve the desired transparent to dark state switching colours. However, this approach can present significant synthetic challenges that typically result in a compromise in device performance parameters such as contrast range or stability as well as solvent processability. In this study we have investigated tuning the dark-state colour of an ECD (at +0.8 V) by solution mixing poly(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine) (PProDOT-(Hx)2), which has an excellent contrast performance but with an esthetically undesirable purple colour transition, with poly(3,3-bis(2-ethylhexyl)-3,4-dihydro-2H-thieno …

In Vitro Growth And Differentiation Of Primary Myoblasts On Thiophene Based Conducting Polymers, Anita F. Quigley, Klaudia K. Wagner, Magdalena Kita, Kerry J. Gilmore, Michael J. Higgins, Robert D. Breukers, Simon E. Moulton, Graeme M. Clark, Anthony Penington, Gordon G. Wallace, David L. Officer, Robert M. Kapsa

Australian Institute for Innovative Materials - Papers

Polythiophenes are attractive candidate polymers for use in synthetic cell scaffolds as they are amenable to modification of functional groups as a means by which to increase biocompatibility. In the current study we analysed the physical properties and response of primary myoblasts to three thiophene polymers synthesized from either a basic bithiophene monomer or from one of two different thiophene monomers with alkoxy functional groups. In addition, the effect of the dopants pTS- and ClO4 - was investigated. In general, it was found that pTS- doped polymers were significantly smoother and tended to be more hydrophilic than their ClO 4 …

Surface And Biomolecular Forces Of Conducting Polymers, Michael J. Higgins, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

In this review, we provide insight into the surface forces of conducting polymers, a class of intelligent materials that offer unique strategies for controlling biomolecular interactions in wide-ranging biomedical applications. Critical to the success of these applications is that the polymer interface is exposed to biological fluids whose interactions are controlled through the polymer surface chemistry and electrochemical switching of the surface properties. There is, however, little known about the intermolecular and surface forces that govern these interactions. Therefore, the purpose of this review is to more closely examine the forces that mediate interactions with biological entities, including forces such …

Comparative Displacement Study Of Bilayer Actuators Comprising Of Conducting Polymers, Fabricated From Polypyrrole, Poly(3,4- Ethylenedioxythiophene) Or Poly(3,4-Propylenedioxythiophene), Babita Gaihre, Syed Ashraf, Geoffrey M. Spinks, Peter C. Innis, Gordon G. Wallace

Australian Institute for Innovative Materials - Papers

The stress gradient generated due to electrochemical oxidation/reduction of a conducting polymer in a bilayer actuator causes a bending movement. Here we report a comparative study of the displacement of bilayer actuators prepared using different conducting polymers. The effects of conducting polymers obtained from electrochemical or chemical synthesis route: different polymers (polypyrrole (PPy), poly(3,4-ethylenedioxythiophene) PEDOT and poly(3,3-dihexyl-3-4-dihydro-2H-thieno[3,4b][1,4]-dioxepine [PProDOT(Hx) 2]); and different electrolytes (0.1 M lithium trifluromethanesulfonate/propylenecarbonate (LiTFSI/PC) and 1-ethyl-3-methyl imidazolium trifluromethanesulfonate (EMITFSI)) on the displacement amplitude and displacement patterns of these actuators were investigated and compared. The results indicate that the bilayer actuator consisting of an electrochemically synthesized conducting polymer …

The Enhancement Of Peroxide-Cured Fluoroelastomer Rubber To Metal Bonding, Richard Hunter Cooke Iii

Browse all Theses and Dissertations

A "combi-cured&" fluoroelastomer (FKM) rubber formulation was designed to yield 100% cohesive rubber failure when cured to cold-rolled steel with derivatives of polymeric silane adhesives. Three different categories of adhesives were tested: Unsaturated Polymeric Silane with Phosphonium Salt (UPSP-D), Unsaturated Polymeric Silane (UPS-L), and Saturated Polymeric Silane (SPS-L). Adhesion Inserts molded using ASTM Method D429 Method C all consistently yielded 100% cohesive rubber failure and showed adhesion strength in the range of 700 to 800 psi after being pulled at 2" per minute until break. After obtaining consistent 100% rubber failure, a design of experiment (DOE) was implemented to determine …

Synthesis And Characterization Of Biodegradable Poly(Vinyl Esters) With Hdac Inhibitory Activity, Kyle Lawrence Horton

Wayne State University Theses

HDAC inhibitors are known to have anti-inflammatory properties. HDAC inhibitors are used in combination with Oct4 to generate induced pluripotent stem cells. I hypothesized that polyesters based on simple aliphatic HDAC inhibitors like valproic acid (VPA) and phenylbutyric acid (PBA) can serve as alternatives to existing polyester biomaterials with improved anti-inflammatory properties and as scaffolds for generation of iPSCs when used in combination with layer-by-layer thin films delivering reprogramming transcription factors. Vinyl ester of phenylbutyric acid (VEPA) and vinyl ester of valproic acid (VEVA) were synthesized from their carboxylic acid precursors using an iridium complex catalyst at yields as high …