It is more than a decade that Ionic Polymer-Metal Composites (IPMCs) have been known as an exciting class of smart materials and attracted growing worldwide attention. IPMCs are soft and flexible, and can generate large and reversible strains in response to electrical stimulus. Thus, they have potential applications in industrial and biomedical fields, as actuators. Before these applications can be realized , however, the performance of IPMCs must be understood and improved through improvement of component characteristics and of preparation methods. In general, the aim of this thesis is to gain a fundamental understanding of the chemical and structural factors that affect the electromechanical performance of IPMCs. To this end, a multi-technique investigation is applied to correlate the electrochemical and electromechanical behavior of IPMCs, during operation, with their chemistry, microstructure and nanostructure. Researchers have suggested several plausible mechanical and mathematical models to reveal that ion transport occurs within IPMCs and that it is an important factor in their actuation performance. However, there is still a need for further experimental studies to help refine our understanding of the actuation mechanism of these materials. In this work, the powerful, non-invasive and non-destructive technique of Magnetic Resonance Imaging (MRI) is employed to study the internal structure and water content distribution in Nafion membranes and also IPMCs. Moreover, MRI is also applied to image electrically-induced diffusion of ions with their associated water molecules in real time, in operating IPMC actuators. This forms the major part of this project and, to the best of our knowledge, it is the first recorded electrochemical experiment of this kind. The size and dimensions of IPMCs can affect their actuation performance. Thus, in this work, model IPMC actuators are prepared based on the available commercial Nafion membrane and fabricated cast Nafion membrane and their electromechanical behaviors are compared. The effect of parameters such as electrode composition and Nafion thickness on actuation behavior is also studied by measuring displacement and force generation of the IPMC actuators during actuation cycles. Simultaneous current and electrochemical measurements are made to correlate electrochemical processes with actuation behavior directly. Scanning electron microscopy (SEM) is also used to study the internal and surface structure of IPMCs.

Ce travail porte sur la caractérisation de matériaux en couches minces par spectroscopie terahertz dépendant du temps. Dans ce but, nous avons élaboré un banc d’analyse spectroscopique dont l’émission et la détection terahertz reposent sur l’utilisation de laser femtoseconde, de semi-conducteurs, de photocommutateurs ultrarapides ou de cristaux électro-optiques. La réponse diélectrique quantitative de matériaux ferroélectriques (titanate de baryum/ - Ba1-xSrxTiO3) déposés sous forme de couches minces, a permis de mettre en évidence l’importance des modes mous de phonon par une étude en température. Enfin, le comportement électromagnétique de polymères conducteurs à base de polyaniline a été effectué notamment leur efficacité de blindage en bande millimétrique et submillimétrique. / This work concerns the characterization of thin film materials by terahertz time domain spectroscopy. For this purpose, we elaborated a terahertz setup in which the terahertz emission and terahertz detection are based on the use of femtosecond laser, semiconductors, ultrafast photoswitches or electro-optic crystals. The study of dielectric function of ferroelectrics thin film (barium titanate/-Ba1-xSrxTiO3) with temperature, give the importance of soft phonon mode. Finally, the electromagnetic behavior of conducting polymers based on polyaniline was made, in particular their shelding effectiveness in millimeter and sub-millimeter length.

Biosensors based on solid-state field-effect transistor as transducer stage using organic semiconducting materials as sensing stage have been developed. Polyaniline thin films galvanostatic electrodeposited were fabricated. Varied electrodeposition parameters were tested, such as deposited charge, current density, deposition time and monomer concentration, besides the tests of a polymeric blend composed of polyaniline and polypyrrole and tested as pH potentiometric extended gate field-effect transistor sensor. Then, biosensors were produced using the one-step electrochemical immobilization process to obtain thin polyaniline films with entrapped glucose oxidase and urease enzymes, to detection of glucose and urea, respectively. The optimized films presented sensitivity, linearity and detection range to glucose of 14.6 ± 0.4 mV/decade, 99.8 % and from 10-4 mol/L to 10-1 mol/L. Two different biosensors were produced based on the enzymatic catalysis of urea with selectivity to ammonium or hydroxyl ions. For ammonium ion selective films, the sensor presented sensitivity, linearity and detection range of 14.7 ± 0.9 mV/decade, 98.2 % and from 10-5 mol/L to 10-1 mol/L. For the hydroxyl ion selective film, the same parameters were 7.4 ± 0.5 mV/decade, 98.1 % and from 10-5 mol/L to 10-1 mol/L. The same functionalized polyaniline thin films were used in optical and conductometric biosensors due to the polyelectrochromic characteristic of the material. Improvement of the field-effect system was possible with the multimodal array of enzymatic biosensor. The device was built using different enzymatic sensing stages connected to the extended gate field effect transistor. The system decreased the time needed to make distinct measurements, showed good response to the variation in solutions pH, to the presence of the reference film and to injection of target analyte in solution in real time measurement. The electrolyte gated organic field-effect transistor based on a polythiophene organic semiconducting layer was developed. A modular enzymatic biosensor for glucose and urea, with a linear response in the range between 10-6 and 10-3 mol/L, was achieved. This biosensor relies on the immobilization the enzymes on gold rods, used as gate electrodes in the devices. The use of the bioreceptors proved to be selective and cross-selective in the devices. The possibility of exchanging the modified gate electrode to detect specific analytes using the same device system allows the modular sensor to be reused and applied for a broad range of applications. Which is the case for explosives molecules, TNT and DNT, biosensor fabricated in the same terms. This biosensor relies on the immobilization of specific binding peptides for TNT and DNT on the gold rod / Biossensores do estado sólido baseados em transistores de efeito de campo como estágio transdutor fabricados com materiais semicondutores orgânicos como estágio de detecção foram desenvolvidos. Filmes finos de polianilina eletrodepositados galvanostaticamente foram fabricados. Parâmetros de eletrodeposição foram testados, como carga depositada, densidade de corrente, tempo de deposição e concentração de monômero, além de testes com compósito polimérico de polianilina e polipirrol e aplicados como sensor de transistor de efeito de campo de porta estendida potenciométrica de pH. Em seguida, os biossensores foram produzidos utilizando-se o processo de imobilização eletroquímica conjunta para obtenção de filmes finos de polianilina com enzimas glicose oxidase e urease imobilizadas, para detecção de glicose e ureia, respectivamente. Os filmes otimizados apresentaram sensibilidade, linearidade e faixa de detecção para glicose de 14,6 ± 0,4 mV/década, 99,8% e de 10-4 a 10-1 mol/L. Dois biossensores diferentes foram produzidos a partir da catálise enzimática da ureia com seletividade para íons amônio ou hidroxila. Para filmes seletivos ao íon amônio, o sensor apresentou sensibilidade, linearidade e faixa de detecção de 14,7 ± 0,9 mV/década, 98,2% e de 10-5 a 10-1 mol/L. Para o filme seletivo ao íon hidroxila, os mesmos parâmetros foram 7,4 ± 0,5 mV/década, 98,1% e de 10-5 a 10-1 mol/L. Os mesmos filmes finos de polianilina funcionalizados foram utilizados em biossensores ópticos e condutométricos devido à característica polieletrocromática do material. A melhoria do sistema foi possível com o arranjo multimodal do biossensor enzimático. O dispositivo foi construído usando diferentes estágios de detecção enzimática conectados ao transistor de efeito de campo de porta estendido. O sistema diminuiu o tempo necessário para fazer medições distintas, mostrou boa resposta à variação no pH da solução, à presença do filme de referência e à injeção do analito alvo em solução na medição em tempo real. Foi desenvolvido o transistor orgânico de efeito de campo com porta eletrolítica, baseado em uma camada semicondutora orgânica de politiofeno. Um biossensor enzimático modular para glicose e ureia, com uma resposta linear na faixa entre 10-6 e 10-3 mol/L, foi alcançado. Este biossensor depende da imobilização das enzimas no eletrodo ouro utilizado como porta nos dispositivos. O uso dos bioreceptores mostrou-se seletivo nos dispositivos. A possibilidade de trocar o eletrodo de porta modificada para detectar analitos específicos usando o mesmo sistema de dispositivos permite que o sensor modular seja reutilizado e com diversas aplicações. Sendo este o caso de moléculas de explosivos, TNT e DNT, com biossensor fabricado nos mesmos termos. Este biossensor depende da imobilização de peptídeos de ligação específica para TNT e DNT no eletrodo de ouro

Le développement de nouveaux matériaux pour augmenter les performances des capteurs biologiques est très important lorsqu'on sait que les signaux électriques constituent la base des évènements biologiques fondamentaux comme l’activité cérébrale, le battement du coeur ou la sécrétion hormonale. Ces signaux cellulaires sont souvent enregistrés avec des sondes qui nécessitent des modifications génétiques ou chimiques. Cependant, des signaux intrinsèques pourraient être exploités directement. Des matrices de microélectrodes extracellulaires (MEAs) et des transistors électrochimiques à base de polymères (OECTs) sont par exemple sensibles aux flux ioniques. Ils sont, de plus, non-invasifs et donnent des informations importantes sur l’activité cellulaire. Cependant, ils ne peuvent différencier les espèces ioniques impliquées dans les signaux pour l’obtention d’une image précise de l’activité électrique. Ce travail de thèse a ainsi consisté dans : le développement de polymères bivalents ion-sensibles et conducteurs électroniques, la démonstration de leur biocompatibilité avec des cellules bêta-pancréatiques, la fabrication de transistors OECTs intégrant ces matériaux et la preuve de concept de son applicabilité comme plateforme non-invasive pour la détection de flux ioniques. / The generation of novel materials to harness the power of biological sensors is extremely attractive because precisely configured electrical activities form the base of key biological events such as brain activity, heart beat or vital hormone secretion. Cellular signals are often recorded using probes that require genetic or chemical manipulation. Intrinsic signals offer the huge advantage to harness these properties without further transformations. Extracellular microelectrode arrays (MEAs) and polymer-based organic electrochemical transistor arrays (OECTs) rely on the movement of ions, are non-invasive and provide some information on cell activity. However, they cannot resolve fluxes of specific species as targeted ions to obtain a precise picture of cell/organ activity. In this context, this work has consisted on the development of multimodal ion-sensing polymers, demonstration of their biocompatibility to beta-cells, the engineer of original OECTs incorporating these materials and demonstration of their viability as non-invasive platform of electrical cell activity and specific ion fluxes.

With the goal of improving chemical detection methods for buried improvised explosive devices (IED’s), the intention of this study is to show that functionalized nano-particles improve the sensing properties of a polymer applied to gas sensors. The approach was reinforcing the polymer, Nafion, with acid-functionalized carbon nanotubes (CNT’s). Ammonia was chosen as the analyte for its similarity to IED byproducts without the dangers of toxicity or explosion. Two sensor platforms were investigated: Quartz crystal microbalances (QCM’s) and microcantilevers (MC’s). Preliminary evaluation of treated QCM’s, via frequency analyzer, showed improvements in sensitivity and fast reversal of adsorption; and suggested increased stability. Tests with coated MC’s also supported the findings of QCM tests. Amplitude response of MC’s was on average 4 times greater when the Nafion coating contained CNT’s. Quantitative QCM testing with gas-flow meters showed that with CNT inclusion: the average number of moles adsorbed increased by 35% (>1.2 times frequency response); sensitivity improved by 0.63 Hz/ppt on average; although the detection threshold decreased marginally; but reusability was much better after extended exposures to concentrated ammonia. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.

Neste trabalho, desenvolvemos blendas de polímeros biodegradáveis e polímeros condutores com objetivo de avaliar o potencial destes materiais para uso em aplicações biomédicas. O polímero condutor polipirrol (PPY) e os polímeros biodegradáveis poli(-caprolactona) (PCL) e poli(3-hidróxido de butirato) (P3HB) foram escolhidos devido à comprovada biocompatibilidade apresentada por cada um destes três polímeros. O PPY foi sintetizado via polimerização em emulsão, utilizando-se o dodecil sulfato de sódio (SDS) como surfactante e o FeCl3 como oxidante e dopante. A morfologia do polímero obtido foi estudada por microscopia eletrônica de varredura e por microscopia eletrônica de transmissão. O PPY se apresentou como agregado de partículas aproximadamente esféricas, com dimensões da ordem de 80 a 200nm. Verificamos que ocorre uma redução significativa do tamanho das partículas formadas, proporcionalmente ao aumento da concentração de SDS. Os ensaios de microanálise por energia dispersiva (EDS) e de espectroscopia de absorção no infravermelho (FTIR) demonstraram a incorporação de SDS ao PPY, o SDS atuando como contra-íon deste polímero. Isto está de acordo com os resultados de condutividade elétrica obtidos para o polímero sintetizado sem o SDS (1.9S/cm) e com 100mM de SDS (23.3S/cm). A seguir, foram preparadas as blendas, dispersando-se as partículas de PPY em matrizes poliméricas de PCL ou de P3HB, sendo a morfologia destas blendas estudada por microscopia eletrônica de varredura. Em blendas de PCL, as partículas de PPY localizam-se principalmente entre os esferulitos da matriz, devido ao processo de cristalização da PCL. Diferentemente, nas blendas de P3HB estas partículas agruparam-se em várias regiões, e não foram localizadas na superfície dos filmes produzidos. A condutividade elétrica obtida para as blendas de PCL e de P3HB, ambas contendo 15% de PPY, foi respectivamente, 20.8mS/cm e 5.5mS/cm. Esta diferença de valores encontrada, parece estar relacionada à formação de uma rede de partículas de PPY na matriz de PCL. Medidas do ângulo de contato da superfície das blendas de PCL e de P3HB mostraram que elas se tornam progressivamente mais hidrofílicas com o aumento da proporção de PPY. Os resultados obtidos neste trabalho indicam que estas blendas podem ser biocompatíveis, justificando o prosseguimento de novos estudos envolvendo métodos de ensaio in vivo, para uma avaliação mais adequada. / Polymers blends making use of two biodegradable polymers, and a conductive one, were synthesized and characterized in the laboratory, aiming at the development of a new material that would combine adequate properties of biodegradability and electrical conductivity. As such, these blends would be suitable for making special devices to be used in biomedical applications. The well known conducting polymer polypyrrole (PPY), was synthesized, then blended with either poly(-caprolactone) (PCL) and poly(3-hydroxybutyrate) (P3HB), both biodegradable, therefore biocompatible, polymers. PPY particles were obtained along the polymerization route, in which SDS (sodium dodecyl sulfate) acted as a surfactant and FeCl3 as the oxidizing and dopant agent. The PPY samples were characterized by scanning and transmission electron microscopy, as spherical particles having 80-200nm in diameter; it was found that final particle size was inversely related to the concentration of SDS used in the synthesis pathway. The particles were further characterized by energy dispersive microanalysis (EDS) and infrared spectroscopy (FTIR), to demonstrate incorporation of the SDS into the PPY. SDS actually behaves as a counterion of the polymer, according to electrical conductivity results of polymer synthesized without SDS (1.9S/cm) or with 100mM SDS (23.3S/cm). This PPY polymer was then blended with either PCL or PHB matrices. The microstructure of the two resulting blends, as investigated by scanning electron microscopy demonstrates PPY particles mostly located within the interstices of spherulites in the PCL blends, whereas in P3HB blends, they formed irregular patches along the matrix. Electrical conductivity for blends containing 15% PPY were: 20.8mS/cm for PCL blends and 5.5mS/cm for P3HB blends. It can be concluded therefore, that these different values obtained for electrical conductivity were related to the particle distribution within the two matrices. Also, hydrophilic properties of the two blends, according to contact angle measurements, seem to correspond to the content of PPY.

As propriedades protetoras à corrosão dos polímeros condutores, especialmente da poli(anilina) (PANI), têm sido amplamente explorada. Entretanto, o mecanismo pelo qual esta proteção é efetuada ainda não foi completamente elucidado. Evidências mostram que a habilidade protetora à corrosão da PANI está ligada à formação de um par galvânico entre o polímero e o metal. Neste trabalho, foi feito um estudo sobre a formação de um par galvânico entre a PANI e diferentes substratos metálicos (zinco, ferro, níquel e cobre) em meios ácidos e neutros. Medidas de potencial de circuito aberto mostram que há a possibilidade de formação de um acoplamento galvânico e medidas de corrente galvânica mostram que há uma corrente galvânica fluindo entre todos os pares PANI-metal. Durante este trabalho, foi sintetizada uma suspensão à base de epóxi e PANI, a qual foi eletroforeticamente depositada sobre um eletrodo de ferro. Medidas de potencial de circuito aberto e impedância em uma solução aquosa de ácido sulfúrico mostraram que o revestimento à base de PANI protegeu o substrato metálico em questão através da formação de um par galvânico entre o metal e o polímero. / The corrosion protection properties of conducting polymers, especially poly(aniline) (PANI) ones, have been widely exploited. However, the mechanism by which this protection is made has not been completely cleared yet. Evidences show the ability of PANI\'s corrosion protection is connected to the building of a galvanic couple between the polymer and the metal. In this work, a study about the building of a galvanic couple between PANI and distinct metallic substrates (zinc, iron, nickel and copper) in acid and neutral environment was done. Measurements of open circuit potential showed the possibility of the building of a galvanic coupling and measurements of galvanic current showed the flux of a galvanic current between all the couples PANI-metal. In the course of this work, a suspension based on epoxy and PANI was synthesized and electrophoretically depositated on a iron electrode. Measurements of open circuit potential and impedance in a aqueous sulfuric acid solution showed that the revestiment based on PANI protected the metallic substrate by the building of a galvanic couple between the metal and the polymer.

Neste trabalho foi realizado o estudo espectroscópico (UV-VIS-NIR, FTIR, Raman e RMN) dos produtos de polimerização da anilina com persulfato de amônio em condições de síntese diferentes da utilizada na síntese padrão da polianilina (pH inicial = 1). A reação foi realizada em meio de HCl (pH inicial = 3) e em meio tamponado (pH = 3). No primeiro caso foi observada a formação majoritária de oligômeros de anilina tipo cabeça-cauda, enquanto que em meio tamponado são formadas macromoléculas com segmentos do tipo 1,4 de Michael de anilina e benzoquinona monoimina com diferentes graus de hidrólise/oxidação, além de unidades tipo fenazina. Esta caracterização está de acordo com as propostas distintas de dois grupos (Surwade et al. e Stejskal et al.), que a princípio pareciam contraditórias. Ainda com relação aos produtos obtidos em meio tamponado (pH = 3), é observada a formação de microesferas com diâmetro entre 3-7 µm. A microscopia Raman juntamente com a espectroscopia Raman ressonante revelou uma correlação entre estrutura tipo fenazina e a formação das microesferas. / In this work it was performed the spectroscopic study (UV-VIS-NIR, FTIR, Raman e NMR) of the polymerization products of aniline and ammonium persulfate using different reaction conditions in relation to the standard polyaniline synthesis (initial pH = 1). The reaction was performed in HCl medium (initial pH =3) and in buffered medium (pH = 3) In the first case it was observed the major formation of aniline oligomers with head-to-tail coupling, while in buffered medium macromolecules with 1,4 Michael-type segments between aniline and benzoquinone monoimine with different hydrolysis/oxidation ratio of iminic groups are formed, in addition to phenazine-like units. This characterization is in accordance to the distinct proposals of two groups (Surwade et al. e Stejskal et al.), which at first seemed contradictory. Again, relative to the products obtained in buffered solution (pH = 3), it is observed the formation of microspheres whose diameter range is 3-7 µm. The use of Raman microscopy and resonance Raman spectroscopy revealed a correlation between phenazine-like structure and the microspheres formation.

Atualmente a fabricação de sensores poliméricos tem sido de grande interesse tecnológico e científico, devido à grande demanda por sensores de diversos tipos em inúmeras aplicações. Nesse contexto, a Embrapa Instrumentação Agropecuária tem buscado o desenvolvimento de novas tecnologias, instrumentação, e sensores; visando a preservação do meio ambiente, tema de grande importância mundial. Muitos produtos comercializados nos países em desenvolvimento não atendem ao padrão de qualidade FAO, e o seu mau uso leva a riscos de contaminação de solos, águas de rios, mananciais, e lençóis freáticos; prejudicando a vida aquática, e consequentemente a vida humana. Este trabalho teve um caráter exploratório, e os objetivos foram a preparação, caracterização e desenvolvimento de unidades sensoriais à base de polímeros, com o intuito de avaliar a qualidade da água através da detecção de vários pesticidas. Utilizou-se uma \"língua eletrônica\" constituída por diferentes unidades sensoriais, nas quais foram depositados filmes de polímeros condutores com composições selecionadas e otimizadas a fim de se obter respostas elétricas características para cada tipo de pesticida. Para tanto: i) sintetizou-se quimicamente os polímeros polianilina e poli(oetoxianilina) e caracterizou-se os mesmos; ii) depositou-se (através de automontagem) filmes ultrafinos dos polímeros condutores poli(o-etoxianilina), polianilina e poli(3,4-etilenodioxitiofeno) sobre microeletrodos interdigitados. Estes filmes foram investigados quanto à sensibilidade frente aos pesticidas; iii) Caracterizou-se espectroscopicamente por técnicas de ultra-violeta visível (UVVIS), e microscopicamente (MEV) os filmes e as interações entre os pesticidas e os polímeros; iv) Caracterizou-se o conjunto de unidades sensoriais através de medidas elétricas de capacitância em corrente alternada através de espectroscopia de impedância e análise estatística de Componentes Principais (PCA). Resultados bastante interessantes foram obtidos, e a \"língua eletrônica\" foi capaz de distinguir águas contaminadas com 1 µ mL-1 de pesticidas, de águas não contaminadas / Nowadays the manufacturing of polimeric sensors has been attractingv technological and cientific interests, due to the demand for different sensors in a large number of applications. In this context. Embrapa Agriculturial Instrumentation rias been looking for the development of new technologies, instrumentation and sensor, envisaging environment monitoring, theme of huge global importance. Many products that are in the market in developing countries do not follow the FAO quality standards and their use can cause risks of contamination to soil and water, damaging the acquatic life and consequently the human life. The aim of this project was the preparation. characterization and development of sensing units made by thin layers of conducting polymers, in order to evaluate the water quality mainly due to contamination of pesticides. To achieve these aims, we made use of an \"electronic tongue\" designed with different sensing units in which conductor polymeric films with specific compositions were deposited, in order to have electric responses for each type of pesticide. For that, the following studies were carried out: i) The polymers PANI and POEA were synthesized and characterized ii) these films (PANI, POEA and PEDOT/PSS) were deposited by self-assembly on gold interdigited microelectrodes. The sensibility of these films to different pesticides was evaluated; iii) the interactions between pesticides and polymers were monitored by visible ultraviolet spectroscopic (UV-VIS) and microscopy techiques (SEM); iv) the sensing units were characterized by impedance measurements and by Principal Component Analysis (PCA). Using eight sensing units with PANI, POEA and PEDOT/PSS films it was demonstrated the possibility to detect some pesticides in concentration of 1 µ mL-1 and to distinguish contaminated samples from non contaminated

Wang Yuhao = 利用X光电子谱和导电原子力显微镜对聚3, 4-乙烯二氧噻酚 : 聚苯磺酸改性的研究 / 王宇昊. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Text in English; abstracts in English and Chinese. / Wang Yuhao = Li yong X guang dian zi pu he dao dian yuan zi li xian wei jing dui ju 3, 4-yi xi er yang sai fen : ju ben huang suan gai xing de yan jiu / Wang Yuhao. / Abstract --- p.ii / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.ix / List of Tables --- p.xiii / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Review of conducting conjugated polymers --- p.1 / Chapter 1.1.1 --- Development of conjugated polymer --- p.1 / Chapter 1.1.2 --- Basic concepts in independent-electron theories of conducting conjugated polymers --- p.2 / Chapter 1.1.2.1 --- "Huckel model and its difficulty, the importance of election-phonon" --- p.2 / Chapter 1.1.2.2 --- The SSH model and dimerization --- p.3 / Chapter 1.1.2.3 --- "Charge carriers in conducting conjugated polymers: soliton, polaron and bipolaron" --- p.5 / Chapter 1.1.3 --- "Poly(3,4-ethylenedioxythiophene) or PEDT" --- p.5 / Chapter 1.1.4 --- Derivatives of PEDT --- p.6 / Chapter 1.1.5 --- Application of PEDT and its derivatives --- p.7 / Chapter 1.2 --- Polymeric light emitting diodes (PLED) --- p.7 / Chapter 1.2.1 --- Invention Polymeric light emitting diodes (PLED) --- p.7 / Chapter 1.2.2 --- Electric structure of PLEDs --- p.7 / Chapter 1.2.3 --- Transition from excitons to photons --- p.8 / Chapter 1.2.4 --- Controlling electron and hole injection --- p.8 / Chapter 1.2.5 --- Application of PEDT-PSS as hole transporting layer in PLED --- p.9 / Chapter 1.2.6 --- "Phase separating in PEDT-PSS blend, removing the PSS rich layer" --- p.9 / Chapter 1.3 --- Motivations of the thesis work --- p.10 / References --- p.10 / Chapter CHAPTER 2 --- INSTRUMENTATION --- p.27 / Chapter 2.1 --- X-ray Photoelectron Spectroscopy --- p.27 / Chapter 2.1.1 --- History of XPS techniques --- p.27 / Chapter 2.1.2 --- Physical Basis --- p.28 / Chapter 2.1.3 --- Chemical Shift of Binding Energy in XPS --- p.29 / Chapter 2.1.4 --- Binding Energy Referencing in XPS --- p.29 / Chapter 2.1.5 --- Sampling Depth of XPS --- p.30 / Chapter 2.1.6 --- Instrumental Setup of XPS --- p.30 / Chapter 2.2 --- Scanning Probe Microscopy --- p.31 / Chapter 2.2.1 --- Introduction --- p.31 / Chapter 2.2.2 --- Atomic Force Microscopy and Conductive Atomic Force Microscopy --- p.31 / Chapter 2.2.3 --- Instrumental Setup for Conductive AFM --- p.32 / Chapter 2.3 --- The Low Energy Ion Beam (LEIB) system at CUHK --- p.32 / Chapter 2.3.1 --- Introduction --- p.32 / Chapter 2.3.2 --- Principle --- p.33 / Chapter 2.3.3 --- Instrumentation Setup --- p.33 / References --- p.33 / Chapter CHAPTER 3 --- Effects of Ar+ bombardment at 500 and 100eV --- p.42 / Chapter 3.1 --- Introduction --- p.42 / Chapter 3.2 --- Sample Preparation --- p.42 / Chapter 3.3 --- Ar+ sputtering and XPS measurement of the sputtered sample. --- p.43 / Chapter 3.4 --- Results and Discussion --- p.44 / References --- p.49 / Chapter CHAPTER 4 --- Effects of annealing on PEDT-PSS thin films studied by XPS and AFM --- p.60 / Chapter 4.1 --- Introduction --- p.60 / Chapter 4.2 --- Sample Preparation --- p.60 / Chapter 4.3 --- XPS measurements and results --- p.61 / Chapter 4.3.1 --- XPS of C 1s core level of PEDT-PSS --- p.61 / Chapter 4.3.2 --- XPS of O 1s core level of PEDT-PSS --- p.62 / Chapter 4.3.3 --- XPS of S 2p core level of PEDT-PSS --- p.62 / Chapter 4.3.4 --- XPS of Valence Band of PEDT-PSS --- p.64 / Chapter 4.4 --- C-AFM measurements and results --- p.65 / Chapter 4.4.1 --- C-AFM measurements on PEDT-PSS --- p.65 / Chapter 4.5 --- Measurements and results about film insolubility and conductivity --- p.65 / Chapter 4.5.1 --- Insolubility measurements --- p.66 / Chapter 4.5.2 --- Conductivity measurements --- p.66 / Chapter 4.5.3 --- Results from the film insolubility and conductivity measurements --- p.66 / Chapter 4.6 --- Conclusion --- p.67 / References --- p.68 / Chapter CHAPTER 5 --- Effects of low energy proton bombardment of PEDT-PSS films studied by XPS and AFM --- p.90 / Chapter 5.1 --- Introduction --- p.90 / Chapter 5.2 --- XPS and c-AFM studies of PEDT-PSS films bombarded by H+ --- p.90 / Chapter 5.2.1 --- Sample preparation --- p.90 / Chapter 5.2.2 --- Results and discussion --- p.90 / Chapter 5.3 --- Conductivity measurements --- p.92 / Chapter 5.3.1 --- Sample preparation for conductivity measurements --- p.92 / Chapter 5.3.2 --- Results and discussion --- p.93 / Chapter 5.4 --- Conclusion --- p.93 / References --- p.93 / Chapter CHAPTER 6 --- Concluding Remarks and Future Works --- p.106 / Chapter 6.1 --- Concluding Remarks --- p.106 / Chapter 6.2 --- Future Work --- p.106 / Chapter APPENDIX --- The SSH model in describing polyacetylene --- p.108 / Chapter Part 1 --- Assumptions of the SSH model --- p.108 / Chapter Part 2 --- Bloch model and SSH model. --- p.113 / Reference --- p.117