Smart skins are integrating an increasing number of functionalities in order to improve the interaction between the systems they equip and their ambient environment. Here we have developed an electromechanical soft actuator with controlled surface texture due to applied thermal gradient via electrical voltage. The device was fabricated and integrated with optimized process parameters for a prepared heater element [doped PEDOT: PSS (poly-(3, 4 ethylenedioxythiophene): poly (styrene sulfonic acid))], a soft actuator (Ecoflex 00-50/ethanol) and overall packaging case [PDMS (polydimethylsiloxane)]. To study a potential application of the proposed smart skin, we analyze the fluid drag reduction in a texture controlled water flow unit. As a result, we obtained a reduction of approximately 14% in the skin drag friction coefficient during the actuation. We conclude that the proposed soft actuator device is a preferred option for a texture-controlled skin that reduces the skin drag friction coefficient.

No description available.

Organic coatings are widely used to lower the corrosion rate of metallic structures. However, penetration of water, oxygen and corrosive ions through pores present in the coating results in corrosion initiation and propagation once these species reach the metal substrate. Considering the need for systems that offer active protection with self-healing functionality, composite coatings containing polyaniline (PANI) conducting polymer are proposed in this study. In the first phase of my work, PANI was synthesized by various methods and characterized. The rapid mixing synthesis method was chosen for the rest of this study, providing PANI with high electrical conductivity, molecular structure of emeraldine salt, and morphology of spherical nanoparticles. PANIs doped with phosphoric and methane sulfonic acid revealed hydrophilic nature, and I showed that by incorporating a long-chain alkylphosphonic acid a hydrophobic PANI could be prepared. The second phase of my project was dedicated to making homogenous dispersions of PANI in a UV-curable resin based on polyester acrylate (PEA). Interfacial energy studies revealed the highest affinity of PEA to PANI doped with phosphoric acid (PANI-PA), and no attractive or long-range repulsive forces were measured between the PANI-PA surfaces in PEA.This is ideal for making conductive composites as, along withno aggregation tendency, the PANI-PA particles might come close enough to form an electrically connected network. Highly stable PEA/PANI-PA dispersions were prepared by pretreatment of PANI-PA in acetone followed by mixing in PEA in small portions under pearl-milling. The third phase of my project dealt with kinetics of the free radical polymerization that was utilized to cure the PEA/PANI-PA mixture. UV-vis absorption studies suggested a maximum allowed PANI-PA content of around 4 wt.% in order not to affect the UV curing behavior in the UV-C region. Real-time FTIR spectroscopy studies, using a laboratory UV source, revealed longer initial retardation of the photocuring and lower rates of crosslinking reactions for dispersions containing PANI-PA of higher than 3 wt.%. The presence of PANI-PA also made the formulations more sensitive to changes in UV light intensity and oxygen inhibition during UV curing. Nevertheless, curing of the dispersions with high PANI-PA content, of up to 10 wt.%, was demonstrated to be possible at either low UV light intensities provided the oxygen replenishment into the system was prevented, or by increasing the UV light intensity to very high levels. In the last phase of my project, the PEA and PEA/PANI-PA coatings, cured under high intensity UV lamps, were characterized. SEM analysis showed small PANI-PA particles to be closely packed within the matrix, and the electrical conductivity of the composite films was measured to be in the range of semiconductors. This suggested the presence of a connected network of PANI-PA, as confirmed by investigations of mechanical and electrical variations at the nanoscale by PeakForce TUNA AFM. The data revealed the presence of a PEA-rich layer at the composite-air interface, and a much higher population of the conductive network within the polymer matrix. High current signal was correlated with a high elastic modulus, consistent with the level measured for PANI-PA, and current-voltage studies on the conductive network showed non-Ohmic characteristics. Finally, the long-term protective property of the coatings was characterized by OCP and impedance measurements. Short-term barrier-type corrosion protection provided by the insulating PEA coating was turned into a long-term and active protection by addition of as little as 1 wt.% PANI-PA. A large and stable ennoblement was induced by the coatings containing PANI-PA of up to 3 wt.%. Higher content of PANI-PA led to poorer protection, probably due to the hydrophilicity of PANI-PA facilitating water transport in the coating and the presence of potentially weaker spots in the film. An iron oxide layer was found to fully cover the metal surface beneath the coatings containing PANI-PA after final failure observed by electrochemical testing. / <p>QC 20141103</p>

Conducting polymer hydrogels (CPHs) is a class of unique materials that synergize the advantages of conducting polymers (CPs) and polymer hydrogels together. It has been employed in many high-performance electrochemical devices for years, such as energy storage and biosensors. However, large limitations of applying CPHs into the abovementioned areas have been facing the researcher for a long time, mainly due to the difficulties from complicated materials synthesis and untenable nanostructures for potential applications. The drawbacks of previously reported CPHs have put numerous disadvantages onto their applications, partially because they have, for example, high prices, untunable microscale or nanoscale architectures, environmentally hazardous properties, and unscalable and time-consuming synthesis processes. In this thesis, we proposed a novel route for carrying out CPHs by one-step organics synthesis at ambient conditions. The CPHs have hierarchically porous nanostructures crosslinked in a three-dimensional (3D) way, which enable its stable mechanical, unique chemical and physical properties, and outstanding electrochemical properties for potential applicability in long-term energy storage devices and highly sensitive biosensors. With highly controllable nanostructures of the CPHs, our novel concept and material system could possibly be utilized in a broad range of electrochemical applications, including but not limited to lithium-ion batteries (LIBs) electrodes, electrochemical capacitors (ECs), biofuel cells, medical electrodes, printable electronic devices, and biosensors. / text

This thesis presents a novel architecture for a sensing element fabricated from a conducting polymer and a bioderived membrane. The thin film device provides controlled, selective ion transport from a chemical concentration and produces measurable electrical signals, ion storage, and small scale actuation. A chemical gradient applied across a bioderived membrane generates ion flow through protein transporters in the presence of a gating signal. A conducting polymer undergoes ion ingress/egress in the presence of an electrical and chemical potential, which causes a change on the polymers conformal backbone. A ligand (or) voltage gated protein in the bioderived membrane results in ion transport through the bioderived membrane. Integrating the two electroactive materials provides a unique architecture which takes advantage of their similarities in ionic function to produce a device with controlled and selective ion transport. The chemoelectromechanical device is one that couples chemical, electrical, and mechanical potentials through number of ions, dielectric displacement, and strain. The prototype consists of a stacked thin conducting polymer film and bioderived membrane which form three aqueous chambers of varying ionic concentrations. The top chamber contains an electrolytic solution, and the bottom chamber contains deionized water adjacent to the conducting polymer. The current that passes through a conducting polymer for an applied electrical signal is based on the level of doping/undoping and therefore can be used as a method of sensing protein function in the sensing element. This architecture results in a sensing element applicable in real time chemical sensors, volatile organic compound detectors, and bioanalytical sensors. The conducting polymer layer is formed from polypyrrole (PPy) doped with sodium dodecylbenzenesulfonate (NaDBS), and the bilayer lipid membrane is formed from 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) reconstituted with the protein alamethicin. The magnitude of current required to span a 175 µm pore was empirically found to be 326.5 A/cm2 and is based on electrode condition, electrode surface area, pyrrole concentration, and electrical potential. A micron-scale pore through a silicon substrate is spanned by a thin PPy(DBS) layer, forming a bridge which supports the bioderived membrane. The bioderived membrane is reconstituted with alamethicin, a voltage-gated protein extracted from trichoderma viride. Ion transport experiments were performed to characterize the PPy(DBS) layer and the bioderived membrane and are represented as electrical equivalents for subsequent analysis. The equivalent impedance of polypyrrole was calculated to be 1.7847±0.1735Ωcm2 and capacitance was calculated to be 1.2673±0.1823µF/cm2. The equivalent impedance of a bioderived membrane was calculated to be 1.654±1.9894MΩcm2, capacitance was calculated to be 1.1221± 0.239µF/cm2, and alamethicin resistance was calculated to be 1.025± 0.7228MΩcm2. Thus, using impedance measurements in the conducting polymer layer, it is proposed that a scaled up sensing element can be fabricated using the suspended polypyrrole supported bioderived membrane.

Organic electrode materials are finding increasing use in energy storage devices due to their attractive properties that allow building of flexible and low weight devices in an environmentally friendlier manner than traditional alternatives. Among these organic electrode materials, conducting redox polymers (CRPs), consisting of conducing polymer (CP) with covalently attached redox active pendant groups (PG), have attracted our interests. This is due to the advantageous synergy between CP and PG, e.g. electronic conductivity, high stability and large charge storage capacity. In this thesis polypyrrole has been selected as CP and quinones as PGs. A series of quinone-pyrrole dyad polymers has been synthesized with a variety of quinone substituents, demonstrating the adjustability of quinone formal potentials by choice of substituents. Importantly, in this series we show that the CP-PG redox match, i.e. that the formal potential of the PG is within the conducting region of the CP, is a requirement for fast charge transfer from the electrode to the PGs. Moreover, a series of quinone-pyrrole dyad polymers with various linkers was synthesized, showing that the choice of linker has a pronounced impact on the interactions between the PG and CP. In addition, the temperature dependence of conductance during doping of the polymers reveals the charge transport mechanism. To summarize, the adjustability of the quinone formal potential as well as the fast charge transport in the bulk material ensures the applicability of the CRPs as electrode materials in organic batteries.

Depuis de nombreuses années des chercheurs imitent le vivant afin d'obtenir des systèmes capables de s'adapter à des environnements de plus en plus complexes. Aujourd'hui aucune des technologies classiques n'est capable de rivaliser complètement avec le fonctionnement d'un muscle. L'objectif de ce travail est de synthétiser et d'intégrer une nouvelle génération d'actionneurs-capteurs à base de réseaux interpénétrés de polymères conducteurs dans des systèmes de perceptions biomimétiques. Nous avons tout d'abord réalisé la synthèse et la caractérisation d'une nouvelle matrice hôte à base de réseaux interprétés de polymères (RIP) combinant de bonnes propriétés mécaniques du caoutchouc nitrile (NBR) et de conductivités ioniques du poly (oxyde d'éthylène). Nous avons ensuite incorporé dans cette matrice hôte un polymère conducteur électronique, le poly (3,4-éthylènedioxythiophène), par polymérisation in situ. Nous avons caractérisé les effets de différents paramètres de synthèse sur la localisation et la morphologie du polymère conducteur au sein de la matrice. Puis nous avons caractérisé les propriétés d'actionneurs et de capteurs de ces matériaux électroactifs. Enfin nous avons réalisé l'intégration de ces matériaux dans deux prototypes de systèmes de perceptions biomimétiques, le premier tactile imitant les vibrisses du rat et le deuxième visuel imitant les muscles oculomoteurs. Finalement, nous concluons que les propriétés et performances de cette nouvelle génération d'actionneurs-capteurs permettent leurs intégrations dans des systèmes de perceptions spécifiques pouvant être utilisés sur un robot mobile. / For many years researchers mimic the living in order to obtain systems that can adapt to complex environments. Today no conventional technology is able to fully compete with the functioning of a muscle. The objective of this work is to synthesize and integrate a new generation of actuators and sensors based on interpenetrating polymer networks of conductive polymers in biomimetic perceptions systems. We first carried out the synthesis and characterization of a novel host matrix based on interpreted polymer networks (IPN) combining good mechanical properties of nitrile rubber (NBR) and ionic conductivities of poly(ethylene oxide ) (PEO). Then, We incorporated into this host matrix an electronically conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), by in situ polymerization. We characterized the effects of various synthesis parameters on the location and morphology of the electrically conductive polymer within the matrix. Then, we characterized the actuation and sensing properties of these électroactive materials. Finally, we completed the integration of these materials into two prototypes of biomimetic perceptions. The first one tactile is imitating and emulating tactile perception of the rat vibrissae. The second one visual is imitating the extraocular muscles. Finally, we conclude that properties and performances of this new generation of sensor-actuators allow their integration into specific perception system that can be used on a mobile robot.

Os polímeros condutores intrínsecos são materiais isolantes ou semicondutores que, quando submetidos a um processo de dopagem, passam a apresentar condutividade próxima à metálica. Dentre os polímeros condutores sintetizados mais estudados está a poli(anilina), (PANI), que apesar de ter sido sintetizada pela primeira vez há aproximadamente 150 anos, continua sendo objeto de estudo de muitos grupos de pesquisa por todo o mundo até hoje. Apesar das características atrativas da PANI (facilidade de preparação e dopagem, estabilidade química e baixo custo), ela é categorizada como um material insolúvel e infusível em condições normais, o que dificulta sua processabilidade e aplicabilidade. Em vista dessas características indesejáveis, muitos derivados da PANI, tais como PANIs substituídas, copolímeros e blendas, são preparados em busca de novos materiais mais solúveis e processáveis. A obtenção do PPSA, um copolímero alternado da PANI e do PPS, mostrou-se atraente devido à possibilidade desse material poder apresentar as propriedades desejáveis de ambos os homopolímeros, juntamente com uma maior solubilidade. Nesta tese, apresentar-se-á a preparação desse polímero bem como sua respectiva caracterização espectroscópica e térmica e a determinação da massa molecular pela técnica de espalhamento de luz. Um estudo do comportamento eletroquímico por voltametria cíclica combinada com técnicas \"in situ\": espectroscopia Raman Ressonante, UV-Visível e por microbalança eletroquímica a cristal de quartzo também será mostrado. / The intrinsic conducting polymers are insulating or semi-conducting materials that show conductivities similar to metals when submitted to a doping process. Polyaniline (PANI), synthesized for the first time 150 years ago, is still the subject of research of many groups in the world, being one of the most studied conductive polymers. Besides its attractive properties (easy synthesise and doping, chemical stability and low cost), PANI is an insoluble and infusible material in normal conditions, what makes its processability and applicability very difficult. In order to overcome these difficulties, many PANI derivatives, such as substituted PANIs, copolymers and blends have been prepared, searching for more soluble materials and processible. PPSA, an alternate copolymer of PANI and PPS, is an attractive alternative because this material can show interesting properties of both homopolymers, together with a higher solubility. In this thesis it will be shown the preparation of this copolymer, as well as its spectroscopic and thermal characterization, and the determination of its molar mass by light scattering. The electrochemical behavior, studied by cyclic voltammetry combined with \"in situ\" techniques such as Raman resonant spectroscopy, UV-VIS and electrochemical quartz crystal microbalance, will also be shown.

Conducting polymer coating is the new developing area in the field of advanced textiles. In this project the rheological behaviour of paste containing conducting polymer was studied during formulation to coating application. The literature study is done by keeping all the contents of project in mind and a wide area of conductive polymer, coating methods, binder system and rheology modifier is covered. The rheological behaviour of different fluid containing newtanion and non-newtanion behaviour is discussed for better understanding of the project working. Polyester fabric was coated by knife coating method. In paste formulation, the chemicals used were polyurethane binder with two HEUR based rheology modifiers. A lot of experiments were performed to determine the right amount of rheology modifier alone or in combination for paste formulation and coating application and interesting findings were observed during the experimental work which had been justified in results and analysis. After application, the coated fabric was checked for resistivity. / Program: Magisterutbildning i textilteknologi

<p>The thesis describes an investigation into the interaction between the conducting polymer and cellulosic materials, and the preparation of electroconductive paper. The adsorption behavior of the conducting polymer onto cellulosic materials was characterized. Poly(3,4-ethylenedioxythiophene) doped with poly(4-styrene sulfonate) (PEDOT:PSS) was used as conducting polymer because of its attractive properties in terms of conductivity, water solubility, and environmental stability. The model substrate used for adsorption was microcrystalline cellulose (MCC). Various pH levels and salt concentrations were explored to completely understand the adsorption behavior of PEDOT:PSS. The variation in surface charge characteristics when the pH and salt concentration were changed was monitored by polyelectrolyte titration and zeta potential measurement. The adsorption isotherm showed a broad molecular distribution of the conducting polymer and considerable interaction between the polymer and MCC. As the pH of the solution was increased, the adsorbed amount decreased. With varying salt concentrations, the adsorption passed through a maximum. The extent of deposition of PEDOT:PSS on the surface of cellulosic fibers was investigated using X-ray Photoelectron Spectroscopy (XPS) with a commercial base paper as substrate. XPS analysis of dip-coated paper samples showed PEDOT enrichment on the surface. The degree of washing the dip-coated paper with acidic water did not significantly affect the PEDOT enrichment on the surface.</p><p> </p><p>A base paper was coated with PEDOT:PSS blends to produce electroconductive papers. The bulk conductivities (σ_dc) of the coated papers were measured using a four-probe technique and impedance spectroscopy. One-side and two-side coating gave comparable conductivity levels. Various organic solvents added to the PEDOT:PSS dispersion at different concentrations showed various effects on the bulk conductivity of the coated paper. Blends containing sorbitol and isopropanol did not enhance the bulk conductivity of the coated paper, and at high concentrations these organic solvents lowered the conductivity. Paper samples coated with a PEDOT:PSS blend containing N-methylpyrrolidinone (NMP) and dimethyl sulfoxide (DMSO) exhibited a higher conductivity than when coated with pure PEDOT:PSS, due to conformational changes and their plasticizing effect. The effect of calendering was investigated and only the sample subjected to 174 kN/m line load after coating showed significant conductivity enhancement. The addition of TiO₂ pigment lowered the bulk conductivity of the paper. Contact angle measurements were made to monitor the effect of coating the paper with PEDOT:PSS blends on the hydrophilicity of the paper samples. The amount of PEDOT:PSS deposited in the fiber network was determined using total sulfur analysis. Thus, this study makes use of conventional paper surface treatment as method for achieving bulk conductivity of paper in the semi-conductor range without significantly decreasing the paper strength.</p> / Printed Polymer Electronics