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1
Malnoë, Thomas. "Développement et caractérisation de condensateurs nano-composites à base de tantale." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S079.
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Le développement des polymères conducteurs, surtout en termes de stabilité, a permis de les intégrer dans les dispositifs électroniques pour des applications à haute valeur ajoutée. C'est la raison pour laquelle les condensateurs tantale initialement basés sur la technologie MnO2, en tant que cathode, ont été améliorés avec le remplacement de cette dernière par un polymère organique conducteur. Ces nouveaux condensateurs tantale-polymère sont constitués d'une anode en tantale frittée, d'un film diélectrique en oxyde de tantale, et d'une cathode en polymère conducteur, typiquement le poly(3,4-éthylènedioxythiophène) (PEDOT). Le fonctionnement des condensateurs a d'abord été optimisé uniquement pour de faibles capacités par polymérisation in situ. L'étape suivante consiste à atteindre de plus grandes capacités par imprégnation du polymère conducteur pré-synthétisé. Notre travail a été axé sur la caractérisation fine et la fabrication de prototypes de condensateur. Pour mener à bien cette étude, chaque partie du condensateur tantale-polymère a été caractérisée par différentes techniques physico-chimiques. Nous avons, entre autres, étudié la microstructure du réseau de tantale et les propriétés de la solution commerciale de polymère conducteur pour déterminer les paramètres d'imprégnation des condensateurs. Les caractérisations effectuées au laboratoire sont complétées par une évaluation des performances électriques des prototypes fabriqués dans l'entreprise. Tout ce travail a contribué à la mise sur le marché d'une nouvelle gamme de condensateurs tantale-polymère par l'entreprise Exxelia Tantalum. En parallèle, une étude a été consacrée à la synthèse d'un nouveau couple de polymère plus performant dans le but de remplacer le polymère commercialThe development of conducting polymers, especially in terms of environmental stability, has allowed them to be used in electronic devices for high value applications. That's why tantalum capacitors initially based on MnO2 cathode technology have been improved by the replacement of it with a conducting polymer. Tantalum-polymer capacitors consist of a sintered tantalum anode, an anodic tantalum oxide film as a dielectric, and a conductive polymer cathode made of poly (3,4-ethylenedioxythiophene) (PEDOT). Until recently, those capacitors have been optimized only for low capacities by in situ polymerization. The next step is to reach higher capacities using an impregnated conductive polymer. Our work focused on the characterization and fabrication of capacitors. The main study focused on the characterization of each part of the tantalum-polymer capacitor via physico-chemical investigations. We studied the microstructure of the tantalum network and the properties of the commercial polymer solution to determine parameters for the dip-coating of tantalum anodes. This laboratory characterization is complemented by an assessment of the electrical performances of samples within the company. All this work has contributed to a new range of tantalum-polymer capacitors by Exxelia Tantalum Company. At the same time, a study has been performed in the synthesis of a new pair of polymers in order to replace the commercial polymer
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Mariani, Federica. "PEDOT:PSS thin films: Applications in Bioelectronics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/11915/.
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Owing to their capability of merging the properties of metals and conventional polymers, Conducting Polymers (CPs) are a unique class of carbon-based materials capable of conducting electrical current. A conjugated backbone is the hallmark of CPs, which can readily undergo reversible doping to different extents, thus achieving a wide range of electrical conductivities, while maintaining mechanical flexibility, transparency and high thermal stability. Thanks to these inherent versatility and attracting properties, from their discovery CPs have experienced incessant widespread in a great plethora of research fields, ranging from energy storage to healthcare, also encouraging the spring and growth of new scientific areas with highly innovative content. Nowadays, Bioelectronics stands out as one of the most promising research fields, dealing with the mutual interplay between biology and electronics. Among CPs, the polyelectrolyte complex poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS), especially in the form of thin films, has been emphasized as ideal platform for bioelectronic applications. Indeed, in the last two decades PEDOT:PSS has played a key role in the sensing of bioanalytes and living cells interfacing and monitoring. In the present work, development and characterization of two kinds of PEDOT:PSS-based devices for applications in Bioelectronics are discussed in detail. In particular, a low-cost amperometric sensor for the selective detection of Dopamine in a ternary mixture was optimized, taking advantage of the electrocatalytic and antifouling properties that render PEDOT:PSS thin films appealing tools for electrochemical sensing of bioanalytes. Moreover, the potentialities of this material to interact with live cells were explored through the fabrication of a microfluidic trapping device for electrical monitoring of 3D spheroids using an impedance-based approach.
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Svensson, Mikael. "Conducting redox polymers for battery applications." Thesis, Uppsala universitet, Strukturkemi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415137.
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The near future will put a lot of demand on the increasing need for energy production and storage. Issues regarding the modern-day battery technology’s environmental benignity, safety and cost to sustain such demands thus serve as a huge bottleneck, necessitating the research into alternative electrochemical energy storage solutions. Conducting redox polymers are a class of materials which combines the concepts of conducting polymers and redox active molecules to work as fully organic electrode materials. In this work three conducting redox polymers based on 3,4-ethylenedioxythiopene and 3,4-propylenedioxythiopene (EPE) with hydroquinone, catechol and quinizarin pendant groups were investigated. The polymers were electrochemically characterized with regards to their ability to cycle protons (aqueous electrolyte) and cations (non-aqueous electrolyte), their kinetics and charge transport and as cathodes in a battery. In non-aqueous electrolyte, hydroquinone and catechol did not exhibit redox activity in a potential region where the backbone was conducting as they were not redoxmatched. Quinizarin showed redox-matching as concluded by in situ conductance and UV-vis measurements when cycling Na+, Li+, Ca2+ and Mg2+-ions in acetonitrile. Comparison of the kinetics revealed that the rate constant for Ca2+-ion cycling was several magnitudes larger than the rest, and galvanostatic charge/discharge showed that 90% of the polymer capacity was attainable at 5C. An EPE-Quinizarin cathode and metallic calcium anode coin cell assembly displayed output voltages of 2.4 V, and the presented material thus shows promising and exciting properties for future sustainable battery chemistries.
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Ruano, Torres Guillem. "Conducting polymers and hybrid materials for technological applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673194.
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Depletion of natural resources and non-renewable energy sources has recently accelerated due to the development of globalized economy and industrialization. During the last years, the scientific community has devoted much of its efforts to developing and improving renewable energy sources. In this context, electrochemical capacitors, or supercapacitors, have received great interest owing to their properties and potential applications. Supercapacitors and their different components constitute the main line of work of the present thesis. More specifically the thesis investigates the use of hydrogels in various distinct functions. The work done in the thesis has been developed both experimentally and corroborated by theoretical studies based on quantum mechanics and molecular dynamics.
The main body of the thesis is divided into three parts. The first one includes the synthesis and characterization of a hydrogel derived from an unsaturated polyesteramide as a solid electrolyte in a supercapacitor. This part consists of the electrochemical characterization of the hydrogel obtained, evaluating the performance of the hydrogel when acting as a solid electrolyte, as well as a study of ion diffusion through the hydrogel carried out with molecular dynamics. These studies allow to obtain the optimal conditions for the synthesis and use of this hydrogel.
The second part is based on the preparation and characterization of a multilayer system as an electrode in a supercapacitor. More specifically, it covers the preparation of a multilayer system consisting of PVA and the conductive polymer PEDOT, prepared by a layer-by-layer process. The chapter also consists of a theoretical study of quantum mechanics in which the movement and changes of a PEDOT monolayer are studied, and allows to elucidate the mechanisms and electronic properties that had not been fully understood at the experimental level.
Finally, the third and last part incorporates the preparation of a multifunctional system consisting entirely of hydrogels. The chapter begins by detailing the preparation of an electrode of a supercapacitor based on a PEDOT hydrogel and alginate. After its characterization as an electrode, other functionalities that can be given to this system are explored. Among them, a reusable and recyclable pressure sensor is prepared to detect pressure changes linearly and with great sensitivity, as well as a controlled drug release system, in particular a controlled release by electrical stimulation of curcumin.Degut al desenvolupament de l'economia globalitzada i la industrialització, s'ha accelerat l'esgotament de recursos naturals i fonts d'energia no renovables. En els últims anys, la comunitat científica ha dedicat una gran part dels seus esforços a desenvolupar i millorar les fonts d'energia renovable. En aquest context, els capacitors electroquímics, o supercapacitors, han rebut un gran interès degut a les seves propietats i potencials aplicacions. El principal camp de treball d'aquesta tesis són els supercapacitors i les diferents parts que els constitueixen, més concretament la tesis estudia l'ús d'hidrogels en diverses funcions diferents. El treball fet a la tesis s'ha desenvolupat tant a nivell experimental com corroborat mitjançant estudis teòrics basats en la mecànica quàntica i la dinàmica molecular. El cos principal de la tesis està dividit en 3 parts. La primera part inclou la síntesis i caracterització d'un hidrogel derivat d'una poliesteramida insaturada com a electròlit sòlid en un supercapacitor. Aquesta part consta de la caracterització electroquímica de l'hidrogel obtingut, avaluant el rendiment de l'hidrogel a l'hora d'actuar com un electròlic sòlid, així com també consta d'un estudi de difusió dels ions a través d¿aquest dut a terme amb dinàmica molecular. Aquests estudis permeten obtenir les condicions òptimes per la síntesis i ús d'aquest hidrogel. La segona part està dedicada a la preparació i caracterització d'un sistema multicapa com a elèctrode en un supercapacitor. Més concretament, es basa en la preparació d'un sistema multicapa format per PVA i el polímer conductor PEDOT, preparat mitjançant un procés capa per capa. El capítol consta també d'un estudi teòric de mecànica quàntica en el que s'estudia el moviment i canvis d'una monocapa de PEDOT, i permet elucidar els mecanismes i propietats electròniques que no s'havien entès completament a nivell experimental. Finalment, l'última part es tracta de la preparació d'un sistema multifuncional format completament per hidrogels. El capítol comença detallant la preparació d'un elèctrode d'un supercapacitor basat en un hidrogel de PEDOT i alginat. Després de la seva caracterització com a elèctrode, s'exploren les altres funcionalitats que se li poden donar a aquest sistema. Es prepara un sensor de pressió reutilitzable i reciclable que permet detectar canvis de pressió linealment i amb una gran sensibilitat, i també es prepara un sistema d'alliberament controlat de fàrmacs, concretament l'alliberament controlat mitjançant estímul elèctric de curcumina
Polimers i biopolimers
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Yang, Yanyin. "Synthesis, characterization, microfabrication and biological applications of conducting polymers." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127316668.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xv, 192 p.; also includes graphics (some col.). Includes bibliographical references (p. 183-192). Available online via OhioLINK's ETD Center
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Hofmann, Anna. "Aqueous dispersions of conducting polymers for opto-electronic applications." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0380/document.
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Dans ce travail, différentes solutions aqueuses de PEDOT: polyelectrolyte ont été synthétisées à partir de polymères anioniques de types polysaccharides et polystyrènes substitués par des groupements bis(sulfonylimide). Leurs morphologies, dopages,comportements rhéologiques ainsi que leurs propriétés opto-électroniques ont notammen tété caractérisés. Une étude systématique a révélé que les polyélectrolytes de masse molaire élevée portant un groupement fortement acide et ayant un squelette rigide permettent d'obtenir un dopage élevé, une dispersion efficace du PEDOT et donc des complexes PEDOT : polyelectrolyte plus conducteurs. L'utilisation du polyelectrolyte PSTFSI en tant qu'agent de complexation pour le PEDOT donne une dispersion stable montrant les caractéristiques d'un gel, ce qui facilite la fabrication de films minces par 'spin coating' ou doctor blade. Les films de PEDOT : PSTFSI ainsi obtenus montrent une transparence élevée et une conductivité de 330S.cm-1. Ces propriétés ont permis de les intégrer avec succès comme matériaux d'électrodes dans des dispositifs OLED, OPV et OECTIn this work different aqueous dispersions of conducting poly(3,4-ethylenedioxythiophene) :polyelectrolyte (PEDOT:polyelectrolyte) complexes,made from anionic polysaccharides and from synthetic bis(sulfonylimide) substituted polystyrenes, have been synthesized and characterized regarding their doping, morphology, rheological behavior and opto-electronic properties. A systematic study revealed, that high molar mass polyelectrolytes with strongly acidic groups and a rigid backbone structure were favorable for a high doping and an efficient dispersion of PEDOT and allowed the development of highly conducting PEDOT:polyelectrolyte complexes. The use of the polyelectrolyte poly(4-styrenetrifluoromethane(bissulfonylimide)) (PSTFSI) as complexing agent for PEDOT resultedin stable dispersions with gel character, which allowed easy processing by spin coating and doctor blading. The obtained PEDOT:PSTFSI films were highly transparent,displayed a conductivity of up to 330S.cm-1 and were successfully integrated as electrodes in OLED, OPV and OECT devices
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Huang, Huan. "Studies on the electrochemistry and applications of conducting polymers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ36137.pdf.
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Li, Guofeng. "Electrochemical functionalization of conducting polymers towards chemical sensing applications." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/30313.
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Yang, Li. "Terephthalate-Functionalized Conducting Redox Polymers for Energy Storage Applications." Doctoral thesis, Uppsala universitet, Nanoteknologi och funktionella material, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-304628.
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Organic electrode materials, as sustainable and environmental benign alternatives to inorganic electrode materials, show great promise for achieving cheap, light, versatile and disposable devices for electrical energy storage applications. Conducting redox polymers (CRPs) are a new class of organic electrode materials where the charge storage capacity is provided by the redox chemistry of functional pendent groups and electronic conductivity is provided by the doped conducting polymer backbone, enabling the production of energy storage devices with high charge storage capacity and high power capability. This pendant-conducting polymer backbone combination can solve two of the main problems associated with organic molecule-based electrode materials, i.e. the dissolution of the active material and the sluggish charge transport within the material. In this thesis, diethyl terephthalate and polythiophenes were utilized as the pendant and the backbone, respectively. The choice of pendant-conducting polymer backbone combination was based on potential match between the two moieties, i.e. the redox reaction of terephthalate pendent groups and the n-doping of polythiophene backbone occur in the same potential region. The resulting CRPs exhibited fast charge transport within the polymer films and low activation energies involved charge propagation through these materials. In the design of these CRPs an unconjugated link between the pendant and the backbone was found to be advantageous in terms of the polymerizability of the monomers and for the preservation of individual redox activity of the pendants and the polymer chain in CRPs. The functionalized materials were specifically designed as anode materials for energy storage applications and, although insufficient cycling stability was observed, the work presented in this thesis demonstrates that the combination of redox active functional groups with conducting polymers, forming CRPs, shows promise for the development of organic matter-based electrical energy storage materials.
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Kojima, Robert Wataru. "Nanostructured composites conducting polymers and metal salts and their applications /." Diss., Restricted to subscribing institutions, 2010. http://proquest.umi.com/pqdweb?did=2026906701&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Tang, Zhexiong. "Inter-polymer complexes of conducting polymers : synthesis, characterization and applications /." View online ; access limited to URI, 2005. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3186923.
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Bremner, Glen. "The electrochemical properties of conducting polymers for energy storage applications." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46550.
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Visetpotjanakit, Suputtra. "Mixed (ion and electron) conducting polymers, with applications in batteries." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/206171/.
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A new method to fabricate 3D batteries using mixed (ion and electron) conducting polymers as electrolytes has been developed. The majority of the work was done using the polymer Poly(1,11-Di(N-pyrryl)-3,6,9-trioxaundecane) (PP2O3) because it demonstrated mixed conducting properties. Methods are presented for synthesising the monomer then polymerising either electrochemically to give films or chemically to give bulk samples or powders. The conductivities of both polymers were determined by Electrochemical Impedance Spectroscopy (EIS). For polymer films prepared electrochemically on conducting substrates, the conductivities were determined as a function of the p-doping level, using a cell containing a liquid electrolyte and an applied bias potential. The results were fitted with a transmission line model and revealed an electronic conductivity varying from 4.20 x10-10 to 1.69 x10-5 S/cm dependent on the doping level, and a relatively constant ionic conductivity of 1.74 x10-6 S/cm. Oxidative treatment by overdoping resulted in a reduction of electronic conductivity by a factor of about 50,000 times smaller at the potential of maximum conductivity, around 0.30 V with a small change in the ionic conductivity. Bulk samples of the chemically prepared polymer were examined between two blocking electrodes. The electronic conductivities of the as-prepared and chemically oxidized samples were both quite low, around 10-7 and 10-8 S/cm, whereas the ionic conductivity of both samples was around 10-5 and 10-6 S/cm. These values were slightly higher than those of the film samples due to a presence of PC plasticiser in bulk samples. Finally the polymers were tested as electrolyte/separators in lithium ion battery cells: the electrochemically treated film was found to be an effective separator between a 3D LiFePO4 positive electrode and a liquid lithium amalgam negative, and the chemically prepared materials showed a capacity of around 150 mAh per gram LiFePO4 in a conventional Li/LiFePO4 cell,. These experiments demonstrate a proof of concept for the use of mixed conducting polymers as electrolytes in lithium battery systems
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Tiu, Brylee David Buada. "Conducting Polymers for Molecular Imprinting and Multi-component Patterning Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1449227860.
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Tran, Hiep Dai. "One-dimensional nanostructures of conducting polymers bulk synthesis and applications /." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1666392581&sid=7&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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Ekiz, Fulya. "Bioactive Surface Design Based On Conducting Polymers And Applications To Biosensors." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614390/index.pdf.
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ABSTRACT
BIOACTIVE SURFACE DESIGN BASED ON CONDUCTING POLYMERS AND
APPLICATIONS TO BIOSENSORS
Ekiz, Fulya
M. Sc., Department of Biotechnology
Supervisor: Prof. Dr. Levent Toppare
Co-Supervisor: Prof. Dr. Suna Timur
June 2012, 88 pages
An underlying idea of joining the recognition features of biological macromolecules
to the sensitivity of electrochemical devices has brought the concept of biosensors as
remarkable analytical tools for monitoring desired analytes in different technological
areas. Over other methods, biosensors have some advantages including high
selectivity, sensitivity, simplicity and this leads to solutions for some problems met
in the measurement of some analytes. In this context, conducting polymers are
excellent alternatives with their biocompatibility and ease of applicability for an
efficient immobilization of biomolecules in preparing biosensors. Using several
materials and arranging the surface properties of the electrodes, more efficient and
seminal designs can be achieved. In this thesis, it is aimed to create new direct
biosensors systems for the detection of several analytes such as glucose and
pesticides thought to be harmful to the environment. Recently synthesized
conducting polymers (polyTBT)(poly(2-dodecyl-4,7-di(thiophen-2-yl)-2H-benzo[ d][1,2,3]triazole) and (poly(TBT 6 -NH2 )
poly(6-(4,7-di(thiophen-2-yl)-2H-benzo[d][1,2,3]triazol-2-yl)hexan-1-amine) were utilized as a matrices for biomolecule immobilization. After successful electrochemical deposition the polymers on the graphite electrode surfaces, immobilization of glucose oxidase (GOx) and choline oxidase (ChO) were carried out. Amperometric measurements were recorded by monitoring oxygen consumption in the presence of substrates at -0.7 V. The optimized biosensors showed a very good linearity with rapid response times and low detection limits (LOD) to glucose and choline. Also, kinetic parameters, operational and storage stabilities were determined. Finally, designed biosensor systems were applied for glucose and pesticide detection in different media.
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Ng, Annie, and 吳玥. "Polymer blend film for photovoltaic applications optical characterization and solar cell performance." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hdl.handle.net/10722/196013.
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Sunlight is sustainable, clean and readily available energy source, which is one of the potential alternatives to the traditional energy sources. Recently, the organic photovoltaics (OPVs), in particular polymer solar cells (PSCs), have attracted increasing attention owing to their outstanding properties such as low cost, lightweight, flexible, allowing vacuum-free fabrication process and thin-film architecture. These advantageous material and manufacturing features of PSCs provide the opportunities for many novel applications. However, the lower power conversion efficiencies (PCEs) of PSCs compared to inorganic solar cells hinder their competition in the marketplace.
This thesis covers the basic principles of the PSC, strategies for enhancing PCEs as well as the recent development of PSCs. The importance of the source materials has been also demonstrated and discussed. Due to a large number of possibilities, limited resources and time, it is not feasible to do all the work experimentally. Therefore, for continuing advance development of PSCs, the device performance should be modeled as a function of material parameters, which requires the knowledge of material properties, in particular the complex index of refraction N= n - ik. Accurate determination of the optical functions of the active layers and light trapping layers commonly used in PSCs by using the spectroscopic ellipsometry (SE) has been demonstrated. In order to acquire reliable solutions, the methodology including multiple sample analysis, combinations of different measurement techniques, selection of models, the rigorous fitting procedures and the independent verification have been proposed. The obtained information can be used in the simulation to optimize device architectures, model device performance as well as characterize novel materials.published_or_final_version
Physics
Doctoral
Doctor of Philosophy
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Forsberg, Julia. "Derivatisation of Betulin for industrial applications : - Green polymers." Thesis, Umeå universitet, Kemiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-66951.
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Cui, Zhenpeng. "Radiation Induced Synthesis of Conducting Polymers and their Metal Nanocomposites." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS165/document.
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L‘objectif du présent travail est de démontrer la versatilité de méthodologie radiolytique et de l‘étendre à la synthèse de différents PCs dans l‘eau. Le poly(3,4-ethylènedioxythiophène), PEDOT, et le polypyrrole, PPy, ont ainsi été préparés avec succès et caractérisés en solution aqueuse, ou après dépôt sur substrat, par des techniques spectroscopiques et microscopiques. La stabilité thermique et la conductivité électrique de ces matériaux radio synthétisés ont été étudiées et comparées aux propriétés des PCs produits par les méthodologies traditionnelles. Nous avons étudié l‘influence de la nature des espèces radiolytiques oxydantes, de la force ionique du milieu, du pH de la solution et de la présence de surfactants, sur le mécanisme de croissance des PCs, sur le rendement de polymérisation, sur la morphologie des matériaux radio synthétisés ainsi que sur les propriétés optiques et électriques de ces derniers. Nous avons utilisé la radiolyse pour la synthèse de nano composites hybrides à base de PCs et de métaux de transition. Plusieurs voies de synthèse ont été développées : synthèse en une ou deux étapes, par oxydation ou réduction des monomères. La nouvelle stratégie de synthèse par radiolyse, qui est décrite dans ce manuscrit, ouvre la voie à la préparation de très nombreuses familles de PCs et de leurs composites, que ce soit en solution aqueuse ou dans des environnements alternatifs (en milieu organique, sur support, en milieu hétérogène), ce qui laisse augurer de nombreuses applications fort prometteusesThe aim of the present work is to demonstrate the versatility of the gamma (γ)-rays based radiolytic method and to extend our methodology to the synthesis of various conducting polymers (CPs) in water in different experimental conditions. Poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) conjugated polymers were successfully prepared and characterized in solution and after deposition by complementary spectroscopic and microscopic techniques. Also their thermal stability and their electrical conductivity were studied and compared with those of CPs prepared by conventional methods. The influence of the nature of radiation-induced oxidizing radicals, of the ionic strength, of the medium, of the pH, of the presence of surfactant-based soft templates on the growth mechanism, on the efficiency of polymerization, on the morphology of the obtained CPs as well as on their absorption and conducting properties was checked. Also, the radiolytic method was extend to the synthesis of CPs/noble metal nanocomposites. Different preparation methodologies were developed based on two-step method and one-pot method, by using oxidation route or reduction route. Our new radiolytic strategy described and extended in this manuscript opens the way for the preparation of different kinds of CPs and CPs nanocomposites not only in aqueous solutions but also in various environments foreshadowing many promising applications
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Best, Adam Samuel 1976. "Lithium-ion conducting electrolytes for use in lithium battery applications." Monash University, School of Physics and Materials Engineering, 2001. http://arrow.monash.edu.au/hdl/1959.1/9240.
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Di, Nicola Francesco Paolo <1988>. "Synthesis and Characterization of New Polymers for Industrial Applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7491/.
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The main topics explored in this thesis regard the synthesis of some new polythiophenes for the preparation of efficient and stable polymeric solar cell with the bulk heterojunction architecture and the study of the mechanism involved in the radical emulsion polymerization of VDF/HFP to obtain copolymers with an optimized thermal and mechanical behavior.
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Fabregat, Jové Georgina. "Conducting polymers and hybrid derivates with specific applications as sensors and bioactive platforms." Doctoral thesis, Universitat Politècnica de Catalunya, 2014. http://hdl.handle.net/10803/279242.
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The principal focus of this Thesis is the development and design of promising hybrid nanocomposites based on conducting polymers with the main objective of achieving applications in the field of biotechnology and biomedicine. The main lines of research can be summarized as follows;1) Preparation, characterization and evaluation of N-substituted polypyrrole derivatives and poly(3,4-ethylenedioxythiophene) (PEDOT) for electrochemical detection of dopamine, one of the neurotransmitters associated to neurological disorders. In order to examine this purpose, different strategies have been taken into account such as, polymerization method using individual or even combined conducting polymers, the incorporation of gold nanoparticles, the use of soft templates, and other approachs. 2) Design of synthetic amino acids bearing an EDOT group to develop peptide-PEDOT hybrids materials based on chemical similarity concepts. The conjugates have shown that the electrical and electrochemical properties of the conducting polymers are preserved. Therefore, one of their potential applications would be as candidates for the development of platforms with bioactive and bioelectrocompatible properties. 3) Preparation and characterization of organic hybrid materials formed by an all-conjugated polythiophene backbone andwell-defined polyethylene glycol (PEG) grafted chains, which have powerful applicability as active surfaces for the selective adsorption of proteins and as bioactive platforms. Among several factors which influence on the structure and properties of graft copolymers, one of the most important is the molecular weight of the PEG chains which provokes a considerably reduction in the backbone conjugation length. 4) Preparation and characterization of new bionanocomposites formed by PEDOT and CREKA, which is a biologically active linear pentapeptide. The incorporation of CREKA into a PEDOT matrix has been carried out under different experimental conditions and has shown a positive effect on the electrochemical properties of conducting polymer and indicating a favourable cellular proliferation due to the ability to bind fibrin.
Some research findings provided in this Thesis have been published or accepted for publication in scientific journals:
1. An electroactive and biologically responsive hybrid conjugate based on chemical similarity. G. Fabregat, G. Ballano, E. Armelin, L. J. del Valle, C. Cativiela and C. Alemán, Polym. Chem., 2013, 4, 1412.
2.Hybrid materials consisting of an all-conjugated polythiophene backbone and grafted hydrophilic poly(ethylene glycol) chains. A.-D. Bendrea, G. Fabregat, L. Cianga, F. Estrany, L. J. del Valle, I. Cianga and C. Alemán, Polym. Chem., 2013,4, 2709.
3.Polythiophene-g-poly(ethylene glycol) graft copolymers for electroactive scaffolds.A.-D. Bendrea, G. Fabregat, J. Torras, S. Maione, L. Cianga, L. J. del Valle, I. Cianga and C. Alemán, J. Mater. Chem. B, 2013,1, 4135.
4.Design of hybrid conjugates based on chemical similarity.G. Fabregat, G. Ballano, J. Casanovas, A. D. Laurent, E. Armelin, Luis J. del Valle, C. Cativiela, D. Jacquemin and C. Alemán, RSC Adv., 2013, 3, 21069.
5.Controlling the morphology of poly(N -cyanoethylpyrrole). G. Fabregat, M. T. Casas, C. Alemán and E. Armelin, J. Phys. Chem. B, 2012, 116, 5064.
7.Ultrathin Films of Polypyrrole Derivatives for Dopamine Detection. G. Fabregat, E. Córdova-Mateo, E. Armelin, O. Bertran and C. Alemán. J. Phys. Chem. C, 2011, 115,14933.8.Nanostructured conducting polymer for dopamine detection.M. Martí, G. Fabregat, F. Estrany, C. Alemán and E. Armelin, J. Mater. Chem., 2010, 20, 10652.El propósito de la presente tesis es el desarrollo y diseño de nanocompuestos híbridos basados ??en polímeros conductores para su posterior aplicación en el campo de la biotecnología y la biomedicina. Las principales líneas de investigación se resumen de la siguiente manera; 1) Preparación, caracterización y evaluación de derivados N-sustituidos de polipirrol y poli(3,4-etilendioxitiofeno ) (PEDOT) para la detección electroquímica de la dopamina, uno de los neurotransmisores asociados a trastornos neurológicos. Para examinar este propósito, diferentes estrategias han sido consideradas, tales como; el método de polimerización empleando polímeros individuales o combinados, la incorporación de nanopartículas de oro, la utilización de templates, etc. 2) Diseño de aminoácidos sintéticos unidos covalentemente con un grupo EDOT y posterior desarrollo de materiales híbridos (péptido - PEDOT). Los materiales híbridos han demostrado conservar las propiedades eléctricas y electroquímicas del polímero base, siendo posibles candidatos para el desarrollo de plataformas bioactivas y bioelectrocompatible. 3) Preparación y caracterización de materiales híbridos orgánicos formados por una cadena principal de politiofeno y cadenas injertadas de polietilenglicol (PEG), los cuales tienen una elevada aplicabilidad como superficies activas para la adsorción selectiva de proteínas y como plataformas bioactivas. 4) Preparación y caracterización de nuevos bionanocomposites formados por PEDOT y CREKA, el cual es un pentapéptido lineal biológicamente activo. La incorporación de CREKA en una matriz de PEDOT se ha llevado a cabo en diferentes condiciones experimentales, y ha demostrado tener un efecto positivo sobre las propiedades electroquímicas del polímero conductor como también proporcionar una mejora en la proliferación celular debido a la capacidad de éste para unirse a la fibrina. Algunos resultados obtenidos en la presente Tesis han sido publicados o aceptados para su publicación en revistas científicas: 1. An electroactive and biologically responsive hybrid conjugate based on chemical similarity. G. Fabregat, G. Ballano, E. Armelin, L. J. del Valle, C. Cativiela and C. Alemán, Polym. Chem., 2013, 4, 1412. 2. Hybrid materials consisting of an all-conjugated polythiophene backbone and grafted hydrophilic poly(ethylene glycol) chains. A.-D. Bendrea, G. Fabregat, L. Cianga, F. Estrany, L. J. del Valle, I. Cianga and C. Alemán, Polym. Chem., 2013,4, 2709. 3. Polythiophene-g-poly(ethylene glycol) graft copolymers for electroactive scaffolds.A.-D. Bendrea, G. Fabregat, J. Torras, S. Maione, L. Cianga, L. J. del Valle, I. Cianga and C. Alemán, J. Mater. Chem. B, 2013,1, 4135. 4.Design of hybrid conjugates based on chemical similarity.G. Fabregat, G. Ballano, J. Casanovas, A. D. Laurent, E. Armelin, Luis J. del Valle, C. Cativiela, D. Jacquemin and C. Alemán, RSC Adv., 2013, 3, 21069. 5. Controlling the morphology of poly(N -cyanoethylpyrrole).G. Fabregat, M. T. Casas, C. Alemán and E. Armelin, J. Phys. Chem. B, 2012, 116, 5064. 7. Ultrathin Films of Polypyrrole Derivatives for Dopamine Detection. G. Fabregat, E. Córdova-Mateo, E. Armelin, O. Bertran and C. Alemán. J. Phys. Chem. C, 2011, 115,14933.8.Nanostructured conducting polymer for dopamine detection.M. Martí, G. Fabregat, F. Estrany, C. Alemán and E. Armelin, J. Mater. Chem., 2010, 20,
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Aradilla, Zapata David. "Design, synthesis, characterization and development of novel organic conducting polymers with technological applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/116773.
Full textAbstract:
In this thesis, a series of novel organic conducting polymers have been synthesized using alternative methods based on
electrochemical techniques, which have allowed to broaden the knowledge in the field of the characterization by means of
topological, spectroscopic, electrochemical and structural techniques. Among the variety of synthesis techniques of
conducting polymers, layer-by-layer (LbL) has been one of the most important to build multilayered systems. Thus, in this
thesis the LbL has shown to be an excellent procedure to explore new applications in the field of energy storage using
conducting polymers. On the other hand, recently, the influence of new sustituents on functionalized conducting polymers has
been proved to modify the structural, optical and physical properties of conducting polymers. Within this context, synthesis of
novel functionalized conducting polymers bearing strong electron-withdrawing sustituents such as cyano group or halide
atoms have been widely studied and characterized throughout this thesis. The presence of these substituents have emerged
as promising candidates in the field of chemical sensors and electrochromic devices. Although the functionality of polymers
or the development of new techniques are excellent procedures to synthesize and to develop new properties on the field of
conducting polymers, it is worth mentioning that the substrate plays a crucial role on the electrochemical field. Accordingly,
the substrates can also modify and change the properties of conducting polymers during the electropolymerization process.
In this way, different substrates were employed in this work with the aim of achieving new applications in the field of corrosion
inhibitors and as supercapacitors. Supercapacitors as energy storage device has been an outstanding application during
this thesis. Thus, the field of nanotechnology has taken an important part in this thesis through development and design of
promising hybrid nanocomposites based on conducting polymers and clay with technological applications and interesting
optoelectronic properties.
The contribution of theoretical techniques based on quantum mechanical calculations have allowed to predict some
electronic and structural properties of conjugated polymers, which could be corroborated experimentally. The quantum
mechanics is a useful tool to check experimental results and to understand mechanisms not fully understood at
experimental level. Therefore, theoretical calculations have provided promising information to obtain new insights in the field
of conducting polymers.La presente tesis se encuentra focalizada en el estudio de nuevos polímeros conductores orgánicos obtenidos a partir de métodos alternativos basados en principios electroquímicos. Entre los principales métodos de polimerización la técnica conocida como capa-a-capa ha emergido con gran fuerza en los últimos años dada sus numerosas ventajas y propiedades. En este contexto, la síntesis de polímeros conductores mediante este procedimiento permitió comprender y analizar el efecto sinérgico entre capas, consiguientemente la caracterización de estos nuevos materiales a partir de técnicas estructurales, espectroscópicas, morfológicas, electroquímicas y ópticas permitió indagar y desarrollar aplicaciones en diferentes campos tecnológicos tales como la electrónica o la corrosión. Otro de los factores que influyen en las propiedades de los polímeros conductores es el proceso de funcionalización. En esta tesis, la incorporación de grupos funcionales con elevado carácter aceptor de electrones centró una parte importante del trabajo, de este modo, los polímeros conductores funcionalizados con átomos halogenados o mediante el grupo ciano evidenciaron una gran influencia en las propiedades físicas, estructurales, ópticas y morfológicas de las estructuras químicas en tiofeno y pirrol. La modificación de determinadas propiedades en estos polímeros permitió desarrollar componentes basados en sensores químicos o dispositivos electrocrómicos. Acorde a esta temática, la modificación de la superficie juega también un papel importante y crucial en las propiedades de los polímeros conductores durante el proceso de síntesis electroquímica. Análogamente al caso de la funcionalización el estudio de la modificación de la superficie denotó una gran expectativa en el desarrollo de nuevos supercondensadores orgánicos, así como una gran alternativa para aplicación como inhibidores de corrosión. Finalmente, en el ámbito experimental de esta tesis, se han orientado estudios en el campo de la nanotecnología en la síntesis y caracterización de nuevos materiales híbridos nanocompuestos con interesantes propiedades optoelectrónicas y electroquímicas. A nivel teórico, la contribución de cálculos teóricos basados en mecánica quántica permitieron predecir determinadas propiedades electrónicas y estructurales de polímeros conductores, cuyos valores fueron corroborados experimentalmente. Así, la química teórica proporcionó un amplio conocimiento en la exploración y comprensión de los mecanismos estructurales de los polímeros conductores.
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Bajpai, Vardhan. "SYNTHESES, CHARACTERIZATION AND APPLICATIONS OF MICRO-/NANO-STRUCTURED CONDUCTING POLYMERS AND CARBON NANOTUBES." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1131983430.
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Koo, Yiu, and 顧耀. "Synthesis of metal-containing thiophene-based conjugated polymers for photovoltaic applications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B41897262.
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Koo, Yiu. "Synthesis of metal-containing thiophene-based conjugated polymers for photovoltaic applications." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B41897262.
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Bahry, Teseer. "Extension of radiolytic procedure to the preparation of conducting polymers in organic solvents : synthesis, characterization and applications." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS328/document.
Full textAbstract:
Dans le présent travail, nous avons étendu aux solvants organiques notre méthodologie radiolytique de synthèse de polymères conducteurs (PCs), initialement développée en solutions aqueuses. Dans ce contexte, la polymérisation des PCs a été étudiée par radiolyse gamma dans différents solvants organiques et sous différentes conditions expérimentales. La synthèse radio-induite a, en particulier, été optimisée dans le dichlorométhane grâce à la variation et à l’ajustement de différents paramètres : atmosphère, dose, débit de dose, concentration des monomères, etc. Cette synthèse a ainsi pu mener à la préparation de différents types de polymères conducteurs : poly (3,4-éthylènedioxythiophène), poly (3-thiophène acétique acide) and Poly (3-hexylthiophène). Ces derniers ont été totalement caractérises en solutions ou après dépôt par des techniques analytiques, spectroscopiques et microscopiques complémentaires. Nous avons en particulier démontré la simplicité et la versatilité de la polymérisation radio-induite de TAA que ce soit dans le dichlorométhane ou dans l’eau, et avons mis en évidence quelques différentes notable entre ces deux voies de synthèse. Nous avons, par ailleurs, évalué l’influence de la nature des espèces radiolytiques oxydantes générées dans le dichlorométhane, via la variation de l’atmosphère de travail (N₂, air ou O₂), sur les propriétés des polymères conducteurs radio-synthétises, en particulier dans le cas de P3HT. Parmi les nombreuses propriétés physiques chimiques que nous avons sondées dans le cas de tous nos polymères conducteurs radio- synthétises les propriétés électroniques et électrochimiques ont fait l’objet d’une attention particulière. Nos matériaux ont alors été incorporés au sien de cellules solaires à pérovskite hybrides organiques-inorganique (PSCs) et y ont été utilisés comme matériaux de transport de trous (HTMs). Notre nouvelle stratégie radiolytique de synthèse décrite et étendu dans le présent manuscrit, ouvre sans aucun doute la voie à la préparation de nouveaux PCs nanostructurés, de morphologie contrôlée et aux propriétés augmentées : par exemple grâce à l’utilisation d’une polymérisation en microémulsions ou par le développement d’une copolymérisation raisonnéeThe extension of our original radiolytic methodology to the use of organic solvents was an important alternative approach to radiation-induced polymerization of conducting polymers (CPs) in aqueous solutions. The polymerization of CPs was studied by using gamma-radiolysis of several organic solvents under different environmental conditions. The optimization of the synthesis conditions of CPs was then conducted into dichloromethane solvent. After optimization of the synthesis conditions (atmosphere, dose, dose rate, concentration of organic monomers, etc.), the use of dichloromethane radiolysis was successfully employed to synthesize various types of conducting polymers: Poly (3,4-ethylenedioxythiophene) (PEDOT), Poly (3-thiophene acetic acid) (PTAA) and Poly (3-hexylthiophene) (P3HT). The radio-synthesized polymers were fully characterized in solution and after deposition by complementary analytical, spectroscopic and microscopic techniques. Also, the simplicity and versatility of radiation induced polymerization of 3-thiophene acetic acid in dichloromethane and in aqueous solutions was demonstrated. The differences between the two radiolysis routes were highlighted. Furthermore, the influence of generating different oxidizing species under different atmospheres (N₂, air or O₂) upon ɣ-irradiation of dichloromethane solutions containing organic monomers was also studied in particular in case of P3HT. The electronic and electrochemical properties were checked for all radio-synthesized CPs. Accordingly, these polymers were then incorporated in hybrid organic and inorganic perovskite solar cells (PSCs) and used as hole transport materials (HTMs). Our new radiolytic strategy described and extended in this manuscript opens the way for the preparation of new nanostructured CPs with controlled morphology and enhanced properties by using microemulsion polymerization and also for the preparation of processable conjugated materials through copolymerization
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Vijayakumar, Vishnu. "Highly oriented conducting polythiophene films for thermoelectric applications." Thesis, Strasbourg, 2020. http://www.theses.fr/2020STRAE004.
Full textAbstract:
Cette thèse concerne la fabrication de matériaux thermoélectriques (TE) à base de films minces orientés de polythiophènes (PBTTT). Le brossage à haute température produit des films minces de cristallinité et d’orientation contrôlées. Différentes méthodes de dopage avec des dopants tels F4TCNQ, F6TCNNQ et FeCl3 ont permis de fabriquer des films polymère conducteurs orientés aux propriétés TE anisotropes. Une combinaison de spectroscopie UV-vis-NIR polarisée et de MET donne accès à l’orientation et à la quantité de dopants intercalés dans les cristaux polymère. Le coefficient de diffusion du dopant est corrélé à la longueur des chaînes alkyls des polymères : les PBTTTs ayant des chaînes alkyls en C12 présentent les meilleurs propriétés TE en raison d’une diffusion rapide et efficace des dopants dans le polymère. Finalement, nous avons étudié l’effet du type de dopant (son électronégativité, sa taille) sur les propriétés TE des films. Le dopage de films orientés de C12-PBTTT avec FeCl3 permet d’atteindre des valeurs records de conductivité de 2.105 S/cm et des facteurs de puissance de l’ordre de 1 mW/mK2The aim of this thesis is to develop new polymeric thermoelectric (TE) materials based on oriented polythiophene (PBTTT) films. High-temperature rubbing produces oriented films of controlled orientation and crystallinity. Various doping methods with suitable dopants (F4TCNQ, F6TCNNQ and FeCl3) produced enhanced TE properties along the rubbing direction. A combination of polarized UV-Vis-NIR spectroscopy and TEM uncovered the amount and orientation of dopants intercalated in the crystals of PBTTT. The diffusion coefficient of dopants is correlated to the length of alkyl side chains : PBTTT with C12 side chains shows the best TE properties because of a fast and effective diffusion of dopants in the polymer films. Finally, we evaluated the impact of dopant (geometry, electronegativity) on the TE properties. Doping oriented PBTTT with FeCl3 helped reach record electrical conductivity of 2×105 S/cm and TE power factors of 1 mW/mK2
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Hangarter, Carlos Maldonado. "Electrochemical synthesis of one-dimensional nanostructures for sensor and spintronic applications." Diss., [Riverside, Calif.] : University of California, Riverside, 2009. http://proquest.umi.com/pqdweb?index=0&did=1957308741&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1269278715&clientId=48051.
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Thesis (Ph. D.)--University of California, Riverside, 2009.Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 12, 2010). Includes bibliographical references. Also issued in print.
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Moutsatsou, Panagiota. "Production and evaluation of electrospun polyaniline/biopolymer composite nanofibres for medical applications." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25673.
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The aim of this study is the production of a nanofibrous electroactive mat and the investigation of its potential use in tissue engineering, and more specifically for wound dressing purposes. The limitations regarding electrospinnability of the conducting polymer will be identified and addressed and the factors related to its biological properties will be evaluated. To this end, conducting polymer, polyaniline (PANI) was chosen as the electroactive component and blend electrospinning was identified as the most suitable method to produce continuous nanofibres containing PANI. Various biocompatible polymers and solvent systems were investigated for their suitability to assist in electrospinning and PEO (polyethylene oxide) and CH (chitosan) were chosen as carrier polymers for blend electrospinning of PANI. Consequently, CSA (Camphor-10-sulfonic acid (β)) doped PANI/PEO and CSA doped PANI/CH conducting nanofibrous mats were produced by electrospinning. The electrospinning windows for both blends were determined by using full factorial experimental designs. The combined effects of the humidity, voltage and flow rate on the fibre morphology and diameter were examined for both blends, demonstrating that the ambient humidity is the critical factor affecting the electrospinning process and determining the electrospinning window for a conducting polymer. Low humidity favors the formation of defect free fibres while high humidity either hinders fibre formation or causes the formation of defects on the fibres. In the case of PANI/PEO blends, different levels of PANI doping were investigated, and high level of doping with CSA was found to lead to the formation of crystalline structures. Data fitting was used to explore the behavior of conducting polymers using the case of PANI/PEO electrospinning and very good agreement between experimental and theoretical predictions was obtained for only a limited range of experimental conditions, whereas deviation was observed for all other sets of conditions. In the case of PANI/CH, the effect of different ratios of conducting polymer in the blend (0:1, 1:3, 3:5 and 1:1) was examined, as for the electrospinnability, resulting 3 nanofibrous morphology, mat contact angle, electrical conductivity, antibacterial activity and cellular biocompatibility. The incorporation of PANI in the electrospinning blend, affected the electrospinnability of the solution, making it more susceptible to RH deviations, and contributed to the decrease of nanofibre diameter. Higher PANI content was found to result in more hydrophobic and more conducting mats. The method that was used to stabilize the PANI/CH mats was also found to affect antibacterial activity and conductivity. The produced blend mats, exhibited antibacterial activity which was higher against Gram positive B. subtilis and lower against gram negative E. coli. The cellular biocompatibility was assessed with human osteoblasts and fibroblasts, in terms of cell proliferation rate as well as cell attachment and morphology. Cells of both cell lines adhered well and showed good growth rates on nanofibrous substrates of all blend ratios when compared to standard tissue culture plastic. Finally, amongst the PANI containing mats, the one of 1:3 PANI:CH ratio, was identified as the best to support osteoblast and fibroblast cell proliferation when compared to the pure chitosan.
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Dogruer, Deniz. "The development of a hydrodynamic model for the segmented ionic polymer metal composite (IPMC) for underwater applications and the potential use of IPMCs for energy harvesting." abstract and full text PDF (free order & download UNR users only), 2006. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1438915.
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Yahyaie, Iman. "Electrical characterization of microwire-polymer assemblies for solar water splitting applications." American Chemical Society, 2011. http://hdl.handle.net/1993/9225.
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The increasing demand for energy and the pressure to reduce reliance on fossil fuels encourages the development of devices to harness clean and renewable energy. Solar energy is a large enough source to fulfill these demands, however, in order to overcome its daily and seasonal variability, it has been proposed that sunlight be harvested and stored in the form of chemical fuels. One potential approach is the photosynthetic splitting of water to store solar energy in the simplest chemical bond, H–H, using a device that includes: semiconducting microwire arrays as light harvesting components, redox catalysts, and a membrane barrier for separating the products of water redox reactions..
However, the harvested solar energy can be lost across the system and it is critical to characterize the electrical properties of each component within the system to quantify how much of this energy will ultimately be coupled to the water splitting reactions. The aim of this research is to develop approaches for characterization of a proposed system of this kind, incorporating individual semiconductor microwires as photoelectrodes (with no redox catalysts) embedded into a candidate conducting polymer membrane to form a single functional unit.
Semiconductor microwires were isolated and using a novel contact formation approach with tungsten probes in a standard probe station, and their current versus voltage properties were characterized. This approach is of particular interest when
ii
considering the limitations of conventional contact formation approaches (e.g. thermal evaporation of contact metals), arising from the small dimensions of the microwires and also the incompatibility of these techniques with many microwire/polymer structures due to the unwanted interactions between polymers, photoresists, etchants and the high temperature lithographic processes.
The electrical properties of different microwires and also the junctions between microwires and two candidate polymers were studied. Specifically, the combination of methyl-terminated silicon microwires and PEDOT:PSS:Nafion demonstrated promising behavior, with a total DC resistance of approximately 720 kΩ (i.e. losses < 16 mV at maximum available photocurrent), making it a suitable candidate for the use in the proposed system. The outcome of these research may be applied to many applications including semiconducting microstructures and conducting polymers.
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Aussawasathien, Darunee. "ELECTROSPUN CONDUCTING NANOFIBER-BASED MATERIALS AND THEIR CHARACTERIZATIONS: EFFECTS OF FIBER CHARACTERISTICS ON PROPERTIES AND APPLICATIONS." Akron, OH : University of Akron, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1145050541.
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Dissertation (Ph. D.)--University of Akron, Dept. of Polymer Engineering, 2006."May, 2006." Title from electronic dissertation title page (viewed 10/11/2006) Advisor, Erol Sancaktar; Committee members, James L. White, Kyonsuku Min, Darrell H. Reneker, Wieslaw Binienda; Department Chair, Sadhan C. Jana; Dean of the College, Frank N. Kelley; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Hu, Qi-Ang. "UV curable resin for ink jet printing on textile substrates." Thesis, Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/8550.
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Ullah, Habib. "First-principles density functional theory study of novel materials for solar energy conversion and environment applications." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/32949.
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To design an efficient solar energy conversion device, theoretical input is extremely important to provide the basic guideline for experimental scientists, to fabricate the most efficient, cheap, and stable device with less efforts. This desire can be made possible if computational scientist use a proper theoretical protocol, design an energy material, then the experimentalist will only invest weeks or months on the synthetic effort. This thesis highlights my recent efforts in this direction. Monoclinic BiVO4 is has been using as a photocatalyst due to its stability, cheap, easily synthesizable, narrow band gap and ideal VB (-6.80 eV vs vacuum) but inappropriate CB (-4.56 eV vs vacuum) edge position, responsible for its low efficiency. We have carried out a comprehensive experimental and periodic density functional theory (DFT) simulations of the pristine, Oxygen defective (Ov), Se doped monoclinic BiVO4 and heterojunction with Selenium (Se-BiVO4), to improve not only its CB edge position but photocatalytic and charge carrier properties. It is found that Ov (1% Oxygen vacancy) and mild doped BiVO4 (1 to 2% Se) are thermodynamically stable, have ideal band edges ~ -4.30 eV), band gaps (~1.96 eV), and small effective masses of electrons and holes. We have also investigated the contribution of Se to higher performance by effecting morphology, light absorption and charge transfer properties in heterojunction. Finally, it is found that Se makes a direct Z-scheme (band alignments) with BiVO4 where the photoexcited electron of BiVO4 recombine with the VB of Se, consequences electron-hole separation at Se and BiVO4, respectively, as a result, enhanced photocurrent is obtained. Theoretical study of β-TaON in the form of primitive unit cell, supercell and its N, Ta, and O terminated surfaces are carried out with the help of periodic DFT. Optical and electronic properties of all these different species are simulated, which predict TaON as the best candidate for photocatalytic water splitting contrast to their Ta2O5 and Ta3N5 counterparts. The calculated bandgap, valence band, and conduction band edge positions predict that β-TaON should be an efficient photoanodic material. The valence band is made up of N 2p orbitals with a minor contribution from O 2p, while the conduction band is made up of Ta 5d. Turning to thin films, the valence band maximum; VBM (−6.4 eV vs. vacuum) and the conduction band minimum; CBM (−3.3 eV vs. vacuum) of (010)-O terminated surface are respectively well below and above the redox potentials of water as required for photocatalysis. Charge carriers have smaller effective masses than in the (001)-N terminated film (VBM −5.8 and CBM −3.7 eV vs. vacuum). However, due to wide band gap (3.0 eV) of (010)-O terminated surface, it cannot absorb visible wavelengths. On the other hand, the (001)-N terminated TaON thin film has a smaller band gap in the visible region (2.1 eV) but the bands are not aligned to the redox potential of water. Possibly a mixed phase material would produce an efficient photoanode for solar water splitting, where one phase performs the oxidation and the other reduction. Computational study of an optically transparent, near-infrared-absorbing low energy gap conjugated polymer, donor−acceptor−donor (D-A-D) with promising attributes for photovoltaic application is reported herein. The D and A moiety on the polymeric backbone have been found to be responsible for tuning the band gap, optical gap, open circuit (Voc) and short-circuit current density (Jsc) in the polymers solar cells (PSC). Reduction in the band gap, high charge transformation, and enhanced visible light absorption in the D-A-D system is because of strong overlapping of molecular orbitals of D and A. In addition, the enhanced planarity and weak steric hindrance between adjacent units of D-A-D, resulted in red-shifting of its onset of absorption. Finally, PSC properties of the designed D-A-D was modeled in the bulk heterojunction solar cell, which gives theoretical Voc of about 1.02 eV. DFT study has been carried out to design a new All-Solid-State dye-sensitized solar cell (SDSC), by applying a donor-acceptor conjugated polymer instead of liquid electrolyte. The typical redox mediator (I1−/I3−) is replaced with a narrow band gap, hole transporting material (HTM). A unique “upstairs” like band energy diagram is created by packing N3 between HTM and TiO2. Our theoretical simulations prove that the proposed configuration will be highly efficient as the HOMO level of HTM is 1.19 eV above the HOMO of sanitizer (dye); providing an efficient pathway for charge transfer. High short-circuit current density and power conversion efficiency is promised from the strong overlapping of molecular orbitals of HTM and sensitizer. A low reorganization energy of 0.21 eV and exciton binding energy of 0.55 eV, confirm the high efficiency of HTM. Theoretical and experimental studies of a series of four porphyrin-furan dyads were designed and synthesized, having anchoring groups, either at meso-phenyl or pyrrole-β position of a zinc porphyrin based on donor–π–acceptor (D–π–A) approach. The porphyrin macrocycle acts as donor, furan hetero cycle acts as π-spacer and either cyanoacetic acid or malonic acid group acts as acceptor. Optical bandgap, natural bonding, and molecular bonding orbital (HOMO–LUMO) analysis confirm the high efficiency pyrrole-β substituted zinc porphyrins contrast to meso-phenyl dyads. DFT study of polypyrrole-TiO2 composites has been carried out to explore their optical, electronic and charge transfer properties for the development of an efficient photocatalyst. Titanium dioxide (Ti16O32) was interacted with a range of pyrrole (Py) oligomers to predict the optimum composition of nPy-TiO2 composite with suitable band structure for efficient photocatalytic properties. The study has revealed that Py-Ti16O32 composites have narrow band gap and better visible light absorption capability compared to individual constituents. A red-shifting in λmax, narrowing band gap, and strong intermolecular interaction energy (-41 to −72 kcal/mol) of nPy-Ti16O32 composites confirm the existence of strong covalent type interactions. Electron−hole transferring phenomena are simulated with natural bonding orbital analysis where Py oligomers found as donor and Ti16O32 as an acceptor in nPy-Ti16O32 composites. Sensitivity and selectivity of polypyrrole (PPy) towards NH3, CO2 and CO have been studied at DFT. PPy oligomers are used both, in the doped (PPy+) and neutral (PPy) form, for their sensing abilities to realize the best state for gas sensing. Interaction energies and amount of charges (NBO and Mulliken charge analysis) are simulated which reveal the sensing ability of PPy towards these gases. PPy, both in doped and neutral state, is more sensitive to NH3 compared to CO2 and CO. More interestingly, NH3 causes doping of PPy and de-doping of PPy+, providing evidence that PPy/PPy+ is an excellent sensor for NH3 gas. UV-vis and UV-vis-near-IR spectra of nPy, nPy+, and nPy/nPy+-X complexes demonstrate strong interaction of PPy/PPy+ with these atmospheric gases. The applications of graphene (GR) and its derivatives in the field of composite materials for solar energy conversion, energy storage, environment purification and biosensor applications have been reviewed. The vast coverage of advancements in environmental applications of GR-based materials for photocatalytic degradation of organic pollutants, gas sensing and removal of heavy metal ions is presented. Additionally, the presences of graphene composites in the bio-sensing field have been also discussed in this review.
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Oesterle, Matthew John. "Silver ion and solvent effects on polystyrene photochemistry." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/27565.
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Groombridge, Paul. "Development of a control system for microwave joining of homogenous and hetrogenous thermoplastic polymers." Thesis, Queensland University of Technology, 1999.
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Lee, Kwang Seok 1973. "Water-dispersible, conductive polyaniline for organic thin-film electronics." Thesis, 2007. http://hdl.handle.net/2152/3733.
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Weng, Yu-Ting, and 翁郁婷. "Applications of conducting polymers in supercapacitors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/76322351164206486437.
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博士國立臺灣大學
化學工程學研究所
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This thesis focuses on the synthesis of novel high-performance supercapacitors based on conducting polymer (CP). In view of potential applications of supercapacitors for electric vehicle and stand-alone renewable energy storage under severe temperatures, much attention has been placed on different performance aspects of the CP-based supercapacitors over widely different temperature ranges other than the room temperature. First, Polypyrrole (PPy) film, doped with p-toluenesulfonate, has been coated onto activated carbon (AC) electrode preform. Although the specific capacitance of the electrode is doubled, from 176 F/g to 352 F/g, with coating of 17.7 wt.% PPy, the capacitance lost nearly 60% after 10,000 cycles at 40 oC, in contrast to 20% loss at 25 oC. It is demonstrated that the problem of accelerated fading at high temperature is effectively alleviated, in conjunction with significant (up to 50%) improvement in power performance, by embedding conductive TiC nanoparticles within the PPy layer via co-electroplating. With addition of 1.7 wt.% of TiC in the composite electrode, the capacitance retain 92% of its initial capacitance under the same cycling conditions (40 oC, 10,000 cycles). The enhanced high-temperature cycling stability has in part been attributed to the reduction in the mismatch of thermal expansion coefficient between the conducting polymer layer and the AC substrate. High conductivity inorganic nanoparticle, TiC, is introduced into PPy/polyvinyl alcohol (PVA) bi-polymers composite to form the particular “core−shell” nanostructurized TiC@PPy/PVA composite by utilizing interfacial polymerization of the shell−forming polymers on the surface of TiC. This nanocomposite possesses high rate performance and stable long term cycle life over a wide operating temperature ranges from −18 to 60 °C. This is attributed to PVA induced enhancement of the mechanical properties of PPy and the aligned nanostructure of PPy/PVA bi-polymers on the surfaces of TiC core nanoparticles, resulting in the reduced resistance of PPy/PVA nanocomposites. Finally, supercapacitor composite electrode containing predominantly (81 wt.%) Poly(3,4-ethylene-dioxythiophene):Polystyrenesulfonate (PEDOT-PSS) conducting polymer (CP) and graphite oxide (GO; 16 wt.%) and carbon nanotube (CNT; 3 wt.%) has been prepared by a solution casting method. The stacking between these carbon additives having very different dimensionality provides a unique skeletal structure that allows for enlarged polymer/electrolyte interface for high-capacitance and for enhanced electronic and ionic conductivities needed for high-power performance. The resulting ternary electrode exhibits nearly ten-fold increase in energy and power performance as compared with pure CP electrode. It possesses a specific capacitance of 365 F/g-electrode over an operating potential window of 2.0 V, and exhibits a specific energy greater than 100 Wh/kg-electrode at the power of nearly 200 kW/kg-electrode with good cycle stability. Given the processing simplicity and outstanding power performance, the present PEDOT-PSSCP-C composite active material is considered possessing great potential for large-scale supercapacitor applications.
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Guimard, Nathalie Kathryn 1979. "Biodegradable electroactive materials for tissue engineering applications." 2008. http://hdl.handle.net/2152/18236.
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This dissertation focuses on the development of biomaterials that could be used to enhance the regeneration of severed peripheral nerves. These materials were designed to be electroactive, biodegradable, and biocompatible. To render the materials electroactive the author chose to incorporate conducting polymer (CP) units into the materials. Because CPs are inherently non-degradable, the key challenge was to create a CP-based material that was also biodegradable. Two strategies were explored to generate a biodegradable CP-based material. The first strategy centered around the incorporation of both electroactive and biodegradable subunits into a copolymer system. In the context of this approach, two bis(methoxyquaterthiophene)-co-adipic acid polyester (QAPE) analogues were successfully synthesized, one through polycondensation (giving undoped QAPE) and the second through oxidative polymerization (giving doped QAPE-2). QAPE was found to be electroactive by cyclic voltammetry, bioerodible, and cytocompatible with Schwann cells. QAPE was doped with ferric perchlorate, although only a low doping percentage was realized (~8%). Oxidative polymerization of a bis(bithiophene) adipate permitted the direct synthesis of doped QAPE-2, which was found to have a higher doping level (~24%). The second strategy pursued with the goal of generating an electroactive biodegradable material involved covalently immobilizing low molecular weight polythiophene chains onto the surface of crosslinked hyaluronic acid (HA) films. HA films are not only biodegradable and biocompatible, but they also provide mechanical integrity to bilayer systems. Dicyclocarbodiimide coupling of carboxylic acids to HA alcohol groups was used to functionalize HA films. The HA-polythiophene composite is still in the early stages of development. However, to date, thiophene has been successfully immobilized at the surface of HA films with a high degree of substitution. The author has also shown that thiophene polymerization can be achieved at the surface of these functionalized films and that the extent of polymer immobilization appears to be affected by the presence of immobilized thiophene. The results reported in this dissertation lead the author to suggest that it is possible to generate biodegradable electroactive materials. Further, she believes that with additional optimization these materials may prove beneficial for the regeneration of peripheral nerves and possibly other tissues that respond favorably to electrical stimulation.text
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Martwiset, Surangkhana. "High temperature proton conducting materials and fluorescent-labeled polymers for sensor applications." 2009. https://scholarworks.umass.edu/dissertations/AAI3379989.
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The majority of this dissertation focuses on proton conducting materials that could be used at high operating temperatures. Higher operating temperatures are desirable as they will increase fuel cell efficiency, reduce cost, and simplify the heat management system. The factors governing proton conduction including segmental mobility, protogenic group identity, and charge carrier density were investigated on a variety of polymers containing 1H -1,2,3-triazole moieties. Proton conductivity measurements were made using AC impedance spectroscopy. Random copolymers and terpolymers of triazole-containing acrylates and poly(ethylene glycol)methyl ether acrylate (PEGMEA) have been synthesized. Conductivity increased with increasing degree of PEG incorporation until reaching a maximum at 30% mole PEGMEA. In comparison to benzimidazole-functionalized polyacrylate with 35% mole PEGMEA, the triazole analog showed a higher proton conductivity, and a less pronounced conductivity temperature dependence. Further increases in conductivity was achieved through the addition of trifluoroacetic acid. To study the effect of charge carrier density on proton conduction, polyacrylates containing a different number of triazole groups per repeat unit were synthesized. The result showed that introduction of more than one triazole per repeat unit did not result in an increase in conductivity as there was an accompanying increase in Tg. To improve the thermal and mechanical properties, triazole groups were tethered to a higher T g backbone polymer, polynorbornene. Introduction of polyhedral oligomeric silsesquioxane (POSS) into triazole-functionalized polynorbornene was also investigated. In a parallel set of investigations, poly(2-(dimethylamino)ethyl methacrylate), PDMAEMA, and copolymers of DMAEMA and methyl methacrylate (PDMAEMA-co-PMMA) were synthesized via atom transfer radical polymerization (ATRP). Fluorescently-labeled PDMAEMAs were synthesized using fluorescent ATRP initiators to ensure the presence of one dye molecule on every polymer chain. PDMAEMAs and PDMAEMA-co-PMMA with different molecular weights have been deposited onto a negatively-charged silica surface via controlled flow deposition. The results show that the polymer deposition rate depends on molecular weight, and is inversely proportional to molecular weight. A preliminary adhesion study of 1-ìm negatively charged silica spheres onto these functionalized surfaces indicates that by varying the molecular weight, the adhesion threshold can be changed. System modeling is being conducted to support experimental observations.
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Lin, Kai-Lun, and 林楷倫. "Development and Investigation of Hybrid Piezoelectric /Conducting Polymers and Their Applications in Power Nanogenerators." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/25159588193710973631.
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Mejia, Michelle Leann. "Synthesis and characterization of electronic materials for photovoltaic applications." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-05-1322.
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Electronic materials are of great interest for use in photovoltaics, sensors, light-emitting diodes, and molecular electronics. Hybrid Inorganic/Organic materials have been studied for device application due to their unique electronic properties. These properties result from the formation of bulk heterojunctions between inorganic (n-type) and organic (p-type) materials. However, due to incomplete pathways for charge transport and poor interfaces between materials, charge trapping and exciton recombination is often high. In an effort to alleviate these problems, we have developed an approach to fabricate bulk heterojunction materials via a seeded growth process. Electropolymerizable Schiff base complexes have been designed, synthesized, and utilized as precursors for conducting metallopolymers. The embedded metal centers are used as seed points for direct growth of size-controllable semiconductor nanoparticles within the polymer film leading to direct electronic communication between the two materials. The synthesis of CdS, CdSe, Ga₂S₃, CuInS₂, CuInSe₂, CuGaS₂, CuGaSe₂, CuGa[subscript x]In[subscript x]-₁S₂, and CuGa[subscript x]In[subscript x]-₁Se₂ has been seen through TEM and EDX. Devices have been fabricated and current studies have focused on the photovoltaic characterization of these materials which have a PCE of 0.11%. As a second but closely related area, polymers have also been studied as organic semiconductors for device applications. However they are hard to process from solution and their polymeric structure can vary. Both of these problems can be solved by using well-defined solution processable oligomers. Thiophene oligomers have been synthesized and characterized through Single Crystal X-Ray Crystallography, Four Point Probe Conductivity, and Powder Diffraction. These oligomers have a well-defined structure and are solution processable from a variety of solvents which can then be used as models to predict and study the properties of polythiophene.text
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Pillai, Rajesh Gopalakrishna. "Electrochemically directed self-assembly and conjugated polymer semiconductors for organic electronic applications." 2010. http://hdl.handle.net/1993/4270.
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The research work presented in this thesis investigates the mechanistic details of conventional as well as electrochemically directed self-assembly of alkylthiosulfates and explores the use of conjugated semiconducting polymers for organic electronic applications. Here, the significance of the use of conjugated polymers is twofold; first, to explore their applications in nanoelectronics and second, the possibility of using them as a top contact on the self-assembled monolayers (SAMs) for molecular electronic applications. Throughout this work, deposition of the organic materials was performed on prefabricated device structures that required no further lithographic or metal deposition steps after modification of the electrodes with the organic molecules.
Self-assembly of alkylthiosulfates on gold are reported to form monolayers identical to those formed from the corresponding alkanethiols. However, these self-assembly processes follow more complex mechanisms of monolayer formation than originally recognized. Studies on the mechanism of alkylthiosulfate chemisorption on gold shows that the self-assembly process is influenced by electrolyte and solvent. Plausible mechanisms have been proposed for the role of trace water in the solvent on conventional as well as electrochemically assisted self-assembly of alkylthiosulfates on gold. Electroanalytical and spectroscopic techniques have been used to explore the mechanistic details of electrochemically directed self-assembly of alkylthiosulfates on gold. It has been found that the self-assembly process is dynamic under electrochemical conditions and the heterogeneous electron transfer process between the organosulfur compound and gold is mediated through gold surface oxide and accompanied by corrosion.
Conducting polymers are serious candidates for organic electronic applications since their properties can be controlled by the manipulation of molecular architecture. Unique electronic properties of conjugated polypyrrole hybrid materials (PPy0DBS-Li+) with immobile dopant anions and mobile cations have been observed and explained on the basis of movement of the cations in an applied electric field. Based on this principle, functioning polymer resistive memory devices have been demonstrated which can be scalable to lower dimensions for nanoelectronics applications. Finally, proof of concept for using a conducting polymer as a top contact in molecular electronic devices created using electrochemically directed self-assembly is demonstrated.
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Raiford, Matthew Thomas. "Creating more effective functional materials: altering the electronics of conducting metallopolymers for different applications." Thesis, 2014. http://hdl.handle.net/2152/30453.
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Conducting metallopolymers possess attractive electronic properties for use in sensors, photoelectronic devices, catalysts, and other applications. Modification of the conducting polymer backbone, through chemical or electrochemical methods, enables control of catalytic, electronic, and optical properties of the metal via inductive modulation of the electron density. Understanding in detail the relationship between the metal and polymer backbone could lead to more effective metallopolymer materials. We hope to study this relationship by probing the band gaps, excited state energy levels, catalytic activity, and sensor function in four metallopolymer systems.
Devices with sub-stochiometric ratios of Cu2ZnSnS4 NPs (CZTS: (Cu2Sn)1-xZn1/xS)(0≥x≥0.75)) grown in Cu(II) conducting metallopolymers were produced to study band gap tuning in hybrid materials. The valence and conductance bands of CZTS (x = 0.60) aligned with the HOMO/LUMO of the Cu(II) metallopolymer. Changing the alignment facilitated charge transfer in the hybrid material, leading to photovoltaic materials with efficiencies of ~0.1%.
Chemoresistive ionophore sensors were developed by incorporating selective binding groups, such as thiourea, into conducting polymer backbones. Thiourea monomers and polymers showed high selectivity for Pb(II) ions over many competitive ions. XPS experiments demonstrated that reversible chelation of Pb(II) ions could be achieved through a simple uptake/rinse process. The conductivity of the thiourea polymer increased fifty-fold, from 7.75×10−2 S/cm2 to 3.5 S/cm2, after Pb(II) exposure. Sensitivity measurements indicated the sensors have limits of detection near 10−10 M.
Highly conjugated ligands were synthesized to explore effective sensitization of visible and near-IR emitting lanthanides. (3,4-ethylenedioxy)thiophene was appended to dipyridophenazine and dipyridoquinoxaline to introduce a group that could be easily electropolymerized. These bi-functional ligands emitted from π-π* and an inter-ligand charge transfer excited states, and therefore, two distinct triplet states were observed. These separate energy pathways allowed for efficient sensitization of both visible (Tb(III), Eu(III), Dy(III)) and near-IR emitting (Nd(III), Yb(III), Er(III)) ions.
Finally, we explored the oxidation of a rhodium-containing conducting metallopolymer and the subsequent effect on the activity of the metal center. Oxidation of the backbone led to ancillary ligand attenuation, allowing for control of the catalytically active species in the conducting metallopolymer. Rh(I,III) monomer and metallopolymer catalytic studies showed potential for new heterogenous/homogeneous hybrid catalysts.text
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Mondal, Sujit Kumar. "Electrochemical Studies Of Polyaniline And Some Of Its Applications." Thesis, 2007. http://hdl.handle.net/2005/646.
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The studies reported in the thesis deal with surface modification of non-platinum metals by coating with electronically conducting polymers, namely, polyanilne (PANI) and polypyrrole (PPY). The oxidation of Г/I2, hydroquinone/quinine and [Fe(CN)6]3-/ [ Fe(CN)6]4-are studied by cyclic voltammetry and chronoamperometry experiments. It has been shown tht the redox reactions, which do not occur on bare stainless steel electrode, occur through electron-transfer mediated by conducting polymers. The effect of heating of polyaniline (PANI) at 80 0C on its electrochemical activity is studies. Although the thermogravimetric analysis indicates that PANI is stable at temperatures up to about 250 0C and it undergoes decomposition at higher temperatures, its intrinsic redox electrochemical activity decreases with duration of heating at a temperature as low as 80 0C . The polymer completely loses its electrochemical activity. The decrease in lectrochemical activity of PANI is attributed to an irreversible loss of water molecules. The reaction order for degradation of PANI is found to be close to unity, and a value of 1.63 X 10-4 s-1 is obtained for the rate constant. The deactivated PANI does not recover its electrochemical activity even after a prolonged treatment in acidic electrolytes. The electrodeposition of PANI is carried out by galvanostatic, potentiostatic and potentiodynamic methods. The impedance data reflect a marked difference between the PANI deposited by static and dynamic methods. Furthermore, the impedance parameters vary with the sweep rate used in potentiodynamic method. Electrochemical impedance spectra of the electrodes are analyzed using a transmission line model consisting of two rails of finite resistances.
Electrochemical deposition of polyaniline (PANI) is carried out on a porous carbon substrate for supercapacitor studies. PANI deposited at 100 mV s-1 sweep rate by potentiodynamic technique on porous carbon substrate is found to possess superior capacitance properties. Capacitance values as high as 1600 F g-1 are obtained and PANI coated carbon electrodes facilitate charge-discharge current densities as hgh as 45 mA cm-2 (19.8 A g-1 ). Electrodes are found to be fairly stable over a long cycle-life, although there is some capacitance loss during the initial stages of cycling. Electrooxidation of ascorbic acid on polyaniline is studied in a fuel-cell. Ascorbic acid (H2A) is employed as fuel and polyaniline (PANI) as the catalyst. H2A is an environmentally and biologically friendly molecule. The catalyst, namely PANI does not consist of any platinum group metal, and at 70 0C , a maximum power density of 4.3 mW cm-2 is obtained at a current density of 15 mA cm-2 . Also, studies on anodically deposited RuO2 for capacitor applications are reported. Cathodic deposition of RuO2 generally produces a mixture of Ru and RuO2 . On the other hand, the anodic depsotion on SS substrates is found to produce RUO2 which is characterized with high power supercapacitance properties. A capacitance value of 274 F g-1 is obtained at a current density of 20mA cm-2 .
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Dyosiba, Xoliswa Lindokuhle author. "Removal of chromium from industrial wastewater using Polypyrrole-based granular nanostructured materials in fixed bed column." 2014. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001655.
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M. Tech. Engineering: ChemicalResearches the usability and efficiency of the synthesized PPy/Al2O3 nanocomposite as adsorbent in Cr(VI) remediation from contaminated wastewaters.The specific objectives of the study are:to synthesise and characterize the PPy/Al2O3 nanocomposite ; to characterize the prepared nanocomposite using several sophisticated instruments such as, SEM, BET, XRD, et cetera ; to carryout batch adsorption equilibrium and kinetics studies for evaluating the performance of the nanosorbent and to gain insight into the underlying adsorption mechanisms.; to apply adsorption equilibrium and kinetic models.; to assess the breakthrough performance of the PPy/Al2O3 nanocomposite for Cr(VI) adsorption by varying operating parameters, in fixed bed column mode and to apply existing mathematical models to predict the performance of fixed bed adsorption systems and to obtain column design parameters.
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Mohammadi, Hourshad 1977. "Mechanistic modeling, design, and optimization of alkaline/surfactant/polymer flooding." 2008. http://hdl.handle.net/2152/18190.
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Alkaline/surfactant/polymer (ASP) flooding is of increasing interest and importance because of high oil prices and the need to increase oil production. The benefits of combining alkali with surfactant are well established. The alkali has very important benefits such as lowering interfacial tension and reducing adsorption of anionic surfactants that decrease costs and make ASP a very attractive enhanced oil recovery method provided the consumption is not too large and the alkali can be propagated at the same rate as a synthetic surfactant and polymer. However, the process is complex so it is important that new candidates for ASP be selected taking into account the numerous chemical reactions that occur in the reservoir. The reaction of acid and alkali to generate soap and its subsequent effect on phase behavior is the most crucial for crude oils containing naphthenic acids. Using numerical models, the process can be designed and optimized to ensure the proper propagation of alkali and effective soap and surfactant concentrations to promote low interfacial tension and a favorable salinity gradient. The first step in this investigation was to determine what geochemical reactions have the most impact on ASP flooding under different reservoir conditions and to quantify the consumption of alkali by different mechanisms. We describe the ASP module of UTCHEM simulator with particular attention to phase behavior and the effect of soap on optimum salinity and solubilization ratio. Several phase behavior measurements for a variety of surfactant formulations and crude oils were successfully modeled. The phase behavior results for sodium carbonate, blends of surfactants with an acidic crude oil followed the conventional Winsor phase transition with significant three-phase regions even at low surfactant concentrations. The solubilization data at different oil concentrations were successfully modeled using Hand's rule. Optimum salinity and solubilization ratio were correlated with soap mole fractions using mixing rules. New ASP corefloods were successfully modeled taking into account the aqueous reactions, alkali/rock interactions, and the phase behavior of soap and surfactant. These corefloods were performed in different sandstone cores with several chemical formulations, crude oils with a wide range of acid numbers, brine with a wide range of salinities, and a wide range of temperatures. 2D and 3D sector model ASP simulations were performed based on field data and design parameters obtained from coreflood history matches. The phenomena modeled included aqueous phase chemical reactions of the alkaline agent and consequent consumption of alkali, the in-situ generation of surfactant by reaction with the acid in the crude, surfactant/soap phase behavior, reduction of surfactant adsorption at high pH, cation exchange with clay, and the effect of co-solvent on phase behavior. Sensitivity simulations on chemical design parameters such as mass of surfactant and uncertain reservoir parameters such as kv/kh ratio were performed to provide insight as the importance of each of these variables in chemical oil recovery. Simulations with different permeability realizations provided the range for chemical oil recoveries. This study showed that it is very important to model both surface active components and their effect on phase behavior when doing mechanistic ASP simulations. The reactions between the alkali and the minerals in the formation depend very much on which alkali is used, the minerals in the formation, and the temperature. This research helped us increase our understanding on the process of ASP flooding. In general, these mechanistic simulations gave insights into the propagation of alkali, soap, and surfactant in the core and aid in future coreflood and field scale ASP designs.text
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Ballantyne, Amy Marisa. "Functionalised polythiophenes : synthesis, characterisation and applications : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Chemistry at Massey University, Palmerston North, New Zealand." 2005. http://hdl.handle.net/10179/1561.
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Conducting polymers display properties such as high conductivity, light weight and redox activity giving them great potential for use in many applications. Polythiophenes have proved to be particularly useful because they are readily functionalised and have good chemical stability. The purpose of this work was to investigate the effect of electron-withdrawing and electron-donating substituents on the synthesis and properties of polythiophenes. Initial work entailed the synthesis of a series of styryl-substituted terthiophenes. Polymerisation of these materials using both chemical and electrochemical methods was found to produce predominantly short chain oligomers (n < 4) and insoluble material that could not be further processed. An analogous series of styryl-substituted terthienylenevinylene materials were electrochemically oxidised for comparison to the terthiophene series. These materials were also found to produce predominantly dimer and short oligomers, but with the expected higher conjugation length than the corresponding terthiophene oligomers. To enhance polymerisation and increase the solubility of the resulting materials, the polymerisation of styryl-terthiophenes with alkyl and alkoxy functionalities was investigated. The properties of the resulting polymeric materials were determined using electrochemistry, mass spectrometry, spectroscopy and microscopy. The alkoxy substituted polymer was found to have a longer average polymer length than the corresponding alkyl derivative (~n = 11 compared to ~n = 6), but was less soluble (78% compared to 100%). It was found, however, that by increasing the alkoxy chain length from 6 carbons to 10 carbons, the solubility of the polymer could be increased to 97% without affecting the average polymer length. The alkoxy-substituted polymers were observed to be very stable in the oxidised, conducting state compared to the alkyl-substituted polymer, which appeared to be more stable in the neutral, non-conducting state. It was found that these soluble materials could be separated into fractions of different length polymers by using sequential soxhlet extractions in different solvents. Preliminary investigations were made into the suitability of these soluble oligomeric and polymeric materials for use in photovoltaic, actuator and organic battery applications and promising results were achieved for actuator and battery functions. In addition, the solubility of these materials allowed nano- and micro-structured fibre and fibril surfaces to be prepared for use in high surface area electrodes.