Conducting polymers have emerged as a class of innovative materials with tunable properties that are useful in a diverse range of applications. For example, the electronic properties and molecular structure of these materials can be modified electrochemically. Reported in 2008, the creation of a conducting polymer hybrid system PPy(Li+DBS-) that exhibits novel time and potential dependent conductivity can be utilized to create dynamic memory. Unlike modern silicon-based devices which are limited by scaling factors such as quantum tunneling, this system is expected to have exceptional scaling properties allowing memory devices to operate down to the low nm range. The work embodied within this thesis describes results based on the scaling properties of PPy(Li+DBS-) from 5 to 45 μm on the potential dependent current transients that are used as a basis for dynamic memory applications. The deviation from theorized conduction systems has led to a thorough understanding of the anisotropic nature of PPy(Li+DBS-) determined through finite elemental simulation methods. The temperature dependence of the system is also studied to verify activation energies associated with carrier and ion mobility.

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Conducting polymers have emerged as a class of innovative materials with tunable properties that are useful in a diverse range of applications. For example, the electronic properties and molecular structure of these materials can be modified electrochemically. Reported in 2008, the creation of a conducting polymer hybrid system PPy(Li+DBS-) that exhibits novel time and potential dependent conductivity can be utilized to create dynamic memory. Unlike modern silicon-based devices which are limited by scaling factors such as quantum tunneling, this system is expected to have exceptional scaling properties allowing memory devices to operate down to the low nm range. The work embodied within this thesis describes results based on the scaling properties of PPy(Li+DBS-) from 5 to 45 μm on the potential dependent current transients that are used as a basis for dynamic memory applications. The deviation from theorized conduction systems has led to a thorough understanding of the anisotropic nature of PPy(Li+DBS-) determined through finite elemental simulation methods. The temperature dependence of the system is also studied to verify activation energies associated with carrier and ion mobility.

No description available.

No description available.

No description available.

Applications that require electrical energy storage are becoming increasingly diverse. This development is caused by a number of factors, such as an increasing global energy demand, the advent of electric vehicles, the utilization of intermittent renewable energy sources, and advances in disposable and organic electronics. These applications will set different demands on their electrical energy storage and, thus, there will be no single technology used for all applications. For some applications the choice of energy storage materials will be extremely important. Conventional batteries and supercapacitors rely on the use of nonrenewable inorganic materials mined from depleting ores, hence, requiring large amounts of energy for their processing. Such materials also add a significant cost to the final product, making them less attractive for large scale applications. Conducting polymers, on the other hand, constitute a class of materials that can be used for organic matter based energy storage devices. The aim of this thesis was to investigate the use of a composite consisting of the conducting polymer polypyrrole (PPy) and cellulose derived from Cladophora sp. algae for electrical energy storage. The polymer was coated onto the cellulose fibers by chemical polymerization resulting in a flexible material with high surface area. By using this composite as electrodes, electrochemical cells consisting of disposable and non-toxic materials can be assembled and used as energy storage devices. The resistances of these prototype cells were found to be dominated by the resistance of the current collectors and to scale with the thickness of the separator, and can hence be reduced by cell design. By addition of nanostructured PPy, the weight ratio of PPy in the composite could be increased, and the cell voltages could be enhanced by using a carbonized negative electrode. Composites of cellulose and poly(3,4-ethylenedioxythiophene) could also be synthesized and used as electrode materials. The porosities of the electrodes were controlled by mechanical compression of the composite or by coating of surface modified cellulose fibers with additional PPy. Finally, the self-discharge was studied extensively. It was found that oxygen was responsible for the oxidation of the negative electrode, while the rate of self-discharge of the positive electrode increases with increasing potential. Through measurements of the charge prior to and after self-discharge, as well as with an electrochemical quartz crystal microbalance, it was found that the self-discharge of the positive electrode was linked to an exchange of the counter ions by hydroxide ions. It is also demonstrated that the self-discharge rate of a symmetric PPy based device can be decreased dramatically by proper balancing of the electrode capacities and by reducing the oxygen concentration. The results of this work are expected to contribute towards future industrial implementation of electric energy storage devices based on organic materials.

Attaching soft long side chain on conjugated polymers will form liguid cystal structure. Our research is to synthesis the polypyrrole with alkyl chains on nitrogen site and carbon site and observe the effects. We observe the phase transition by X-ray and DSC. But it is hrad to observe because of its absorbing light. Between observing, we just can find the liguid crystal transition on the polypyrrole with octadecane alkyl side chain on nitrogen site. Besides, we can find the 2.8Å and 3.2Å peaks By shearing and solvent casting. Such a phenomenon is common in conjugated polymers. But it is hard to explain. Besides, substituted on different sites will bring different results. Substituted on nitrogen site will lead to bigger d-sapcing than substituted on carbon site. This is because of the difference on co-planity. By the correlation function, we can realize that longer side chain, bigger fluctuation, but better layer structures.

Polypyrrole nanocylinders were fabricated by chemically synthesizing polypyrrole within the pores of nanoporous polycarbonate particle track-etched membranes and alumina membranes. The morphology of the nanostructures was characterized by transmission electron microscopy and scanning electron microscopy. The polycarbonate membrane-templated nanocylinders were cigar-shaped, with the diameter at the center being up to 2.5 times the diameter at the ends. The nanostructures produced in alumina membranes were linear aggregates of blobs. The electrical conductivity of the nanocylinders was measured by leaving the nanocylinders embedded in the insulating template membrane and measuring the trans-membrane resistance. The smallest diameter polycarbonate membrane-templated nanocylinders exhibited a slightly lower conductivity relative to the larger diameter nanocylinders. The temperature dependence of the resistance with and without the application of a magnetic field was in accordance with Mott variable range hopping at temperatures above 5 ± 1 K and Efros-Shklovskii variable range hopping at temperatures below 5 ± 1 K. Based on the measurements in the Mott regime, the localization length, the density of states at the Fermi energy, and the temperature dependence of the average hopping distance were calculated. / Thesis / Master of Science (MS)

Le polypyrrole (PPy), l'un des polymères conducteurs de type p, a démontré un potentiel considérable dans les applications biomédicales et le stockage d'énergie en raison de sa conductivité électrique intrinsèque, sa facilité de synthèse, son potentiel de modification chimique et sa biocompatibilité. En raison de la conjugaison étendue dans ses chaînes moléculaires et de son état d'agrégation, les mauvaises propriétés mécaniques et le manque de processabilité du PPy ont été des défis scientifiques et technologiques exceptionnels. En outre, le PPy possède une bioconductivité, mais aucune bioinductivité, c'est-à-dire une absence de biofonctionnalité, ce qui constitue un autre défi pour le PPy lorsqu'il est utilisé pour des applications biomédicales. Cette thèse se concentre principalement sur ces deux défis auxquels le PPy fait face, c’est-à-dire le manque de biofonctionnalité et la mauvaise performance mécanique. En se basant sur la différence des réactivités chimiques des comonomères, les particules de poly(pyrrole-co-(1- (2-carboxyéthyl)pyrrole structurées en noyaux-coquilles (P(Py-PyCOOH)) ont été synthétisées. Elles sont constituées d'un noyau composé d’un copolymère de P(Py-PyCOOH) riche en PPy et d'une coque composée de PPy-COOH. Les paramètres expérimentaux de polymérisation en émulsion ont été étudiés pour définir les conditions optimales. L'anticorps d’albumine de sérum humain (anHSA), en tant que molécule modèle a été immobilisé par des liaisons covalentes sur la surface des particules et a été prouvé réactif aux antigènes. Un schéma a été proposé pour illustrer la formation des particules de cœur-coquille (P(Py-PyCOOH)) selon un nouveau mécanisme basé sur les réactivités du comonomère. Cette méthode de fabrication peut permettre de préparer des particules de PPy fonctionnelles en grande quantité. La chimie de surface et de masse, la conductivité et le rendement global des particules peuvent être régulés. Pour la première fois, une membrane en PPy souple et mécaniquement traitable (PPy-N) a été préparée par polymérisation interfaciale assistée par modèle (TIP) sans modification chimique des monomères ni autres matériaux. Les structures uniquement interconnectées et multicouches ont été considérées comme responsables de l'excellente souplesse aux températures ambiante et à -196 °C. Un mécanisme basé sur la nature exothermique de la polymérisation du pyrrole a été suggéré pour expliquer les morphologies du PPy-N. Cette membrane en PPy flexible a un poids léger (9 g m-2), une grande surface (14,5 m2 g-1), un comportement électrothermique stable, une amphiphilicité et une excellente cytocompatibilité. Enfin, une nouvelle approche modulaire a été proposée pour immobiliser les protéines sur une surface micro/nano structurée. L'albumine de sérum bovin (BSA) et la HSA ont été immobilisées de manière covalente sur la surface des particules (P(Py-PyCOOH) avant qu’elles soient assemblées sur la surface de la membrane PPy-N pour construire une surface biofonctionnée avec la coexistence de deux types de biomolécules. Cette approche sépare la greffe de protéines et l'immobilisation en deux étapes indépendantes, fournissant ainsi une méthode simple et hautement flexible pour concevoir et fabriquer une surface ou un échafaudage multi-biofonctionnalisé. / Polypyrrole (PPy), one of p-type conducting polymers, has shown considerable potential in biomedical applications and energy storage owing to its inherent electrical conductivity, ease of synthesis, possibility of further chemical modification, and biocompatibility. Due to the extensive conjugation in PPy chains and the aggregation state, the poor mechanical property and processability of pristine heterocyclic PPy have been the outstanding scientific and technological challenges. Moreover, PPy only possesses bioconductivity but no bioinductivity, i.e., lack of biofunction, which is another challenge for PPy when it is applied in biomedical applications. This thesis mainly focuses on these two issues of PPy, i.e., the lack of biofunctionality and the poor mechanical performance. Based on the difference in comonomer reactivity, the core-shell structured poly(pyrrole-co-(1-(2-carboxyethyl)pyrrole)) (P(Py-PyCOOH)) particles were synthesized, comprising the pyrrole (Py) dominated P(Py-PyCOOH) copolymer as the core and PPyCOOH homopolymer as the shell. Experimental parameters of emulsion polymerization were investigated to define the optimal conditions. Anti-human serum albumin antibody (anHSA) as a model molecule was covalently immobilized onto the particle surface and proven reactive to its antigen. A schema was proposed to illustrate the formation of the core-shell (P(Py-PyCOOH)) particles based on a new reactivity-driven mechanism. This fabrication method can be used to prepare functional PPy particles in large-scale. The surface and bulk chemistry, conductivity, and the overall yield of the particles can be regulated. For the first time, a soft and mechanically processable PPy membrane (PPy-N) was prepared by template assisted interfacial polymerization (TIP) with neither chemical modification of the monomers nor compounding with any other materials. The uniquely interconnected and multilayered structures were considered responsible for the excellent flexibility at both room temperature and -196 °C. A mechanism based on the exothermic nature of pyrrole polymerization was suggested to explain the morphology of the PPy-N. Such a flexible PPy membrane has lightweight (9 g m-2), large surface area (14.5 m2 g-1), stable electrothermal behavior, amphiphilicity, and excellent cytocompatibility. Finally, a novel modular approach was proposed to immobilize proteins to a micro/nano structured surface. Bovine serum albumin (BSA) and HSA were covalently immobilized onto the surface of the (P(Py-PyCOOH)) particles prior to their assembly onto the surface of the PPy-N membrane, to construct a biofunctionalized surface with the coexistence of two types of biomolecules. This approach separates protein grafting and immobilization into two independent steps, providing an easy and highly flexible method to design and fabricate multi-biofunctionalized surface or scaffold.