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La légèreté, simplicité et robustesse des systèmes mécaniques binaires font en sorte qu'ils sont une alternative prometteuse aux systèmes analogiques employés de nos jours dans des applications en robotique et en mécatronique. Les performances de systèmes mécaniques binaires sont présentement restreintes par la complexité, le poids et le coût des actionneurs conventionnels. De nouvelles technologies d'actionneurs, telles celles des matériaux intelligents (Smart Materials), doivent donc être développées afin de permettre l'essor et la commercialisation de systèmes binaires performants. Les actionneurs diélectriques en polymère (Dielectric Elastomer Actuators : DEA) sont capables de grandes déformations et de hautes énergies volumiques. Toutefois, l'application de cette technologie d'actionneurs à des systèmes binaires concrets est présentement limitée par la faible fiabilité de ces actionneurs et les faibles énergies volumiques développées par les configurations de DEAs actuelles. Afin de permettre l'avancée de la technologie des DEAs dans des applications binaires, cette recherche propose des configurations antagonistes et bistables qui développent ~10x plus d'énergie volumique que les configurations bistables développées antérieurement. De plus, cette recherche investigue les impacts des techniques de fabrication sur la fiabilité des actionneurs.

Valve stem seal leakage is a major source of fugitive emissions, and controlling these emissions can result in added expense in leak detection and repair programs. Elastomeric O-rings can be used as valve stem seals, and O-ring manufacturers recommend lubrication of elastomeric seals to prevent damage and to assure proper sealing. In this research, a metallic coating was applied as a lubricant using a vacuum vapor deposition process to the surface of elastomeric valve stem seals. Valve stem leak measurements were taken to determine if the coated O-rings, alone or with the recommended lubrication, reduced valve stem seal leakage. This research determined that the metallic coating did not reduce valve stem leakage.

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.

Les nanocomposites à matrice polymère et plus particulièrement les élastomères chargés intéressent depuis de nombreuses années la communauté scientifique du fait notamment de leurs bonnes propriétés mécaniques. Il est établi que l'amélioration des propriétés mécaniques observées dans les élastomères renforcés par des charges nanoscopiques est principalement due à des effets de structure (dispersion des charges) et à des effets d'interface (interactions charges/matrice). Afin d'alimenter la discussion sur l'origine du renforcement dans les élastomères chargés, cette étude s'intéresse à la synthèse et à la caractérisation de nanocomposites modèles pour lesquels les interactions charges/matrice et la microstructure sont maîtrisées. En parallèle, ce travail propose également une analogie entre ces systèmes et les ionomères, matériaux constitués de macromolécules sur lesquelles des groupements ioniques sont greffés. Ces matériaux ionomère présentent des propriétés originales et permettent la création de nœuds de réticulation réversibles avec la température / In polymer-based nanocomposites macroscopic properties are driven by one specific feature: the huge interfacial area developed by nanofillers, leading to a strong improvement in mechanical properties. Even though the molecular origins of this reinforcement are still not well understood, its amplitude appears to be strongly related to two main effects: a structural effect (dispersion state) and an interfacial effect (filler/matrix interactions). The present project aims at developing and studying organic-inorganic nanocomposite materials based on an elastomeric matrix and spherical nanoparticles. A specific attention is paid to get tailored interactions and microstructures, different model nanocomposites are obtained with interesting and original thermo-mechanical properties. In parallel, this work also gives an analogy between these nanocomposite and ionomers, polymer chains on which ionic groups are grafted. These ionomer materials show original mechanical properties and allow creating reversible crosslink nodes with temperature

There is a growing interest in the field of Dielectric Elastomer Actuators (DEAs).A DEA consists of a thin DE lm coated with a compliant electrode. It expandsin planar directions and contracts in thickness under a driving voltage. Becauseof the similar actuation capability compared with human muscles, it is oftenreferred as artificial muscle. One possible application is to integrate the DEA inwearable devices for tremor suppression. In this thesis, the development of theDEA has been advanced towards this application in three aspects: performanceenhancement, modelling accuracy and self-sensing control. The results presented demonstrate that the combination of pre-strain and motion constraining enhances the force output of the DEA significantly but it also leads to the pre-mature electric breakdown that shortens the operational life. This drawback was suppressed by optimising the electrode configuration to avoid the electrically weak regions with low thickness across the DE lm, together with the lead contact o the active electrode region. The durability of the enhanced DEA was therefore improved significantly. Polyacrylate, a commonly used DE, was characterised for dynamic mechanical loading and electrical actuation. The conventional Kelvin-Voigt model was proved to be deficient in simulating the viscoelastic behaviour of polyacrylate in the frequency domain. The error in modelling was substantially reduced using a higher material model that contains multiple spring-damper combinations. It allows the system dynamics to be shaped over frequency ranges. A detailed procedure was given to guide the parameter identification in higher order material model. A novel self-sensing mechanism that does not require superposition of drivingvoltage and excitation signal was also designed. It reconfigures the conventionalDEA to have separate electrode regions for sensing and actuating. As the DElm deforms under driving voltage, the capacitive change in the electrode regionfor sensing was measured via a capacitor bridge and used as the feedback foractuation control. The self-sensing DEA can, therefore, be implemented with anyhigh voltage power supply. Moreover, the sensing performance is demonstratedto have improved consistency without interference of the electrical field. It alsohas a unique feature of DE lm wrinkling detection.

O objetivo no presente trabalho foi avaliar a fidelidade dimensional de troqueis de gesso tipo IV (Vel-Mix®), obtidos a partir de moldes de um único elastômero (Impregum® F), utilizando-se duas diferentes técnicas de moldagem (com casquete ou com moldeira de estoque). A fidelidade de cada troquel obtido foi avaliada através de uma coroa-padrão, a qual encaixava-se com alta precisão ao troquelpadrão, o qual era a estrutura original a ser moldada. Assim foram compostos os 4 seguintes grupos, com o aquecimento do molde não tendo sido efetuado apenas no primeiro deles: 1- do casquete de resina, sem contato com a porção cervical do troquel-padrão (Cstsa); 2- do casquete, também sem o referido contato (Cstca) ; 3- novamente do casquete, agora com contato (Cctca) e 4-. da moldeira de estoque perfurada (Mca). Com base nos resultados encontrados nas condições estabelecidas, após o respectivo tratamento estatístico, foi possível concluir que: 1 - o pior desempenho ocorreu com a moldeira perfurada, com um desajuste médio da ordem de 397, 70 micrometros; 2 - o casquete com toque e com aquecimento (desajuste médio de 85,37 micrometros) apresentou desempenho semelhante ao do casquete sem toque e sem aquecimento (desajuste médio de 102,38 micrometros) e 3 - o melhor desempenho ocorreu com o casquete sem toque e com aquecimento, com um desajuste médio de 0, 03 micrometros. / The aim in this study was to evaluate the dimensional accuracy of dies made with a type IV stone (Vel-Mix®) dies, obtained from moulds of a sole elastomer (Impregum® F), by employing 2 different moulding techniques, with a shell or with a perforated stock tray. Stone dies accuracy was measured by means of a standard crown which could be accurately fitted to the standard die, the original structure to be moulded. In this way, the following 4 groups were stablished, with the mould heating not being done only in the first of them: 1- with the acrylic resin shell cervically not contacting the standard die; 2- with the refered shell but without that contact; 3- once more with the shell, again with that contact and 3- with the stock tray. Under the stablished conditions, after statistical treatment of results, the following conclusions could be drawn: 1- worst performance was presented by the stock tray, with a 397,70 µm mean inaccuracy; 2- the shell performance with cervical contact and heated (85,37 µm mean inaccuracy) was similar to that of it without contact and without heating (102,38 µm mean inaccuracy) and 3- better performance was presented by shell without contact and with heating, with a 0,03 µm mean inaccuracy.

Este trabalho visa a caracterização estrutural, mecânica e óptica de elastômeros de uretâno/uréia (PU/PBDO), baseados em óxido de poli(propileno) e poli(butenodiol), puro, após inflação em tolueno e dopados com ferrofluido. As proporções em massa (%) de PU e PBDO utilizadas são 40/60, 50/50, 60/40 e 80/20. As análises estruturais foram feitas através das técnicas de microscopia óptica de luz polarizada, microscopia de força atômica e magnética, e microscopia confocal de varredura laser com as quais foi verificado que os filmes são isotrópicos e autofluorescentes. A amostra após inflação com tolueno não apresenta diferença em sua textura em relação a amostra pura. As amostras dopadas apresentam coloração marrom devido aos grãos magnéticos. Também verificamos que o processo de dopagem com inflação dos filmes em solução de tolueno e ferrofluido é eficiente, uma vez que o filme não apresenta grandes agregados de grãos magnéticos. Medidas do coeficiente de absorção óptica mostraram que o tempo de inflação das amostras em tolueno não altera de forma significativa esses filmes. Também verificamos que o tempo, de imersão do filme na solução de tolueno e ferrofluido, para que as amostras incorporem a maior quantidade de grãos magnéticos aumenta com a concentração de PU. O número de grãos magnéticos na matriz elastomérica não aumenta depois que a amostra atinge o nível de saturação. Experimentos mecânicos e ópticos mostram que o processo de preparação do elastômero (casting) introduz uma anisotropia estrutural nas amostras opticamente isotrópicas. Esse fato foi evidenciado pelas medidas do módulo de Young e orientação do eixo óptico das amostras sob estiramento. A dependência da diferença de fase e consequentemente da birrefringência óptica em amostras puras, após inflação com tolueno e dopadas com ferrofluido, com a deformação é linear. O coeficiente de deformação óptico também é linear com a concentração de ferrofluido. Para todos os tempos de inflação em tolueno e ferrofluido as amostras 50/50 e 60/40 foram as que apresentaram maior birrefringência induzida por estiramento. / This work aims the structural, mechanical and optical characterization of urethane/urea elastomers (PU/PBDO), based on polypropylene oxide and polybutadiene diol, pure, after swelling in toluene and doped with ferrofluid. The ratios in weight % of PU and PBDO used are 40/60, 50/50, 60/40 and 80/20. The structural analysis were made through of polarized light microscopy, atomic and magnetic force microscopy, and confocal laser scanning microscopy techniques in such was verified that films are isotropics and autofluorescents. The sample after swelling with toluene does not present difference in its texture compared with pure sample. Doped samples present brown color due the magnetic grains. It was also verified that doping process by swelling of film in solution of ferrofluid with toluene is efficient because the film not shows large aggregates of magnetic grains. Measurements of optical absorption coefficient show that the swelling time of the samples in toluene does not modify significantly these films. We verified that the immersion time of the film in the solution of ferrofluid with toluene, to incorporate in the greatest quantity of magnetic grains in samples, increases with the PU concentration. The number of magnetic grains in the elastomeric matrix does not increase after the samples reach the saturation level. Mechanical and optical experiments show that the elastomer preparation procedure (casting) introduces a structural anisotropy in the optically isotropic sample. This result was evidenced by the measurements of the Young\'s module and orientation of the sample\'s optic axis under stretching. The dependence of phase shift, and, consequently the optical birefringence, with strain in pure, after swelling in toluene and doped with ferrofluid samples, is linear. The strain-optic coefficient is linear with the concentration of ferrofluid. For all the swelling time in toluene and ferrofluid the 50/50 and 60/40 samples were those that present the greatest induced birefringence under stretching.

Touch is one of the less exploited sensory channels in human machine interactions. While the introduction of the tactile feedback would improve the user experience in several fields, such as training for medical operators, teleoperation, computer aided design and 3D model exploration, no interfaces able to mimic accurately and realistically the tactile feeling produced by the contact with a real soft object are currently available. Devices able to simulate the contact with soft bodies, such as the human organs, might improve the experience. The existing commercially available tactile displays consist of complex mechanisms that limit their portability. Moreover, no devices are able to provide tactile stimuli via a soft interface that can also modulate the contact area with the finger pad, which is required to realistically mimic the contact with soft bodies, as needed for example in systems aimed at simulating interactions with virtual biological tissues or in robot-assisted minimally invasive surgery. The aim of this thesis is to develop such a wearable tactile display based on the dielectric elastomer actuators (DEAs). DEAs are a class of materials that respond to an electric field producing a deformation. In particular, in this thesis, the tactile element consists of a so-called hydrostatically coupled dielectric elastomer actuator (HC-DEAs). HC-DEAs rely on an incompressible fluid that hydrostatically couples a DEA-based active part to a passive part interfaced to the user. The display was also tested within a closed-loop configuration consisting of a hand tracking system and a custom made virtual environment. This proof of concept system allowed for a validation of the abilities of the display. Mechanical and psychophysical tests were performed in order to assess the ability of the system to provide tactile stimuli that can be distinguished by the users. Also, the miniaturisation of the HC-DEA was investigated for applications in refreshable Braille displays or arrays of tactile elements for tactile maps.

Submitted by RENATO CARVALHO RESENDE (htc.renato@gmail.com) on 2017-03-30T23:23:31Z No. of bitstreams: 1 Dissertação Mestrado Renato Carvalho Resende.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2017-04-06T14:17:14Z (GMT) No. of bitstreams: 1 resende_rc_me_bauru.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) / Made available in DSpace on 2017-04-06T14:17:14Z (GMT). No. of bitstreams: 1 resende_rc_me_bauru.pdf: 9175175 bytes, checksum: 3d504c6ae855f8c5ee734700afd5a7cc (MD5) Previous issue date: 2017-03-06 / Os elastômeros termoplásticos (TPE) têm sido bastante empregados em substituição às borrachas tradicionais, por terem custo reduzido de matéria prima, facilidade no processamento e serem recicláveis. Apresentam propriedades mecânicas semelhantes, porém quando utilizados em componentes de vedação apresentam limitada resistência à corrosão em água clorada. Assim, o desenvolvimento de tratamento superficial que não modifique as características originais, mas tornem o material mais resistente são desejáveis. Para tanto, este trabalho pretende desenvolver uma metodologia a plasma para melhorar esse quesito. O elastômero termoplástico de copoliéster (COPE) foi escolhido por ser o mais empregado em componentes de vedação. O tratamento a plasma de baixa pressão com hexafluoreto de enxofre (SF6) foi empregado visando tornar a superfície do COPE hidrofóbica através da incorporação de grupos fluorados. A implantação iônica por imersão em plasmas (IIIP) de argônio foi utilizada para criar uma camada superficial mais coesa e entrelaçada, além da possibilidade de torná-la hidrofóbica após envelhecimento. Para o tratamento com SF6, os parâmetros de excitação do plasma (12 Pa e 80 W) foram mantidos, variando-se o tempo do tratamento entre 2 e 180 minutos de modo a encontrar uma condição ótima para esse processo. Para a IIIP de Ar os parâmetros de excitação do plasma (5 Pa e 60 min) foram mantidos e a potência da radiofrequência foi variada entre 10 e 150 W. A energia de superfície e ângulo de contato foram obtidos pelo método da gota séssil em um goniômetro automatizado. A morfologia da superfície foi avaliada por microscopia eletrônica de varredura (MEV) e microscopia de força atômica (AFM). Espectroscopia de energia dispersiva (EDS) e espectroscopia de fotoelétrons de raios X (XPS) foram utilizadas para análises da composição química e estrutura molecular. Corrosão por plasma de O2 e imersão em água clorada foram utilizados para avaliar a resistência antes e após os tratamentos a plasma. Os resultados mostram que as amostras tratadas por 90, 120 e 180 minutos em plasmas de SF6 tornam-se hidrofóbica, mesmo após o envelhecimento, apresentando incorporação de flúor, alterando assim a composição química e morfológica da superfície do COPE. Melhorias substanciais foram observadas nessas amostras após os ensaios de corrosão, indicando que um aumento na vida útil do material em situações reais de uso possam ter sido alcançadas. A IIIP de Ar tornou as amostras inicialmente mais hidrofílicas do que a amostra como-recebida, porém após a ação do tempo, algumas amostras permaneceram hidrofóbicas enquanto outras amostras retornaram à condição inicial. Apesar da hidrofobicidade não ter sido alcançada em todas as amostras, alterações na rugosidade e na morfologia foram verificadas, principalmente nas amostras tratada com 100 W de potência do plasma, ocasionando em melhora na resistência do COPE à água clorada. Essa melhora na resistência é atribuída ao aumento da conectividade da estrutura pelo estabelecimento de reticulações geradas pelo processo de IIIP, densificando o material tornando a permeação de íons da solução mais difícil. / Thermoplastic elastomers have been widely used in substitution for conventional rubber, given that the feedstock is cheaper, easier to process and recyclable. Its mechanical properties are similar, but when applied to sealing components its resistance is limited due to the chlorine present in water, therefore, it is interesting to develop a surface treatment that do not alter the original characteristics, but make the material more robust. To achieve such result, we chose to submit the copolyester thermoplastic elastomer (COPE) to plasma. This material was naturally chosen, once it is widely used for sealing purposes in this specific industry. By using low pressure plasma with sulfur hexafluoride, we expect to alter COPEs surface by incorporating fluorine groups, thus making it hydrophobic. We also submitted the sample to a second treatment, by submersion to argon plasma, making the outer layer less defective and more entangled with aging, as observed in previous experiments. For SF6 treatment, the exiting plasma parameters (12Pa and 80W) were kept and the treatment time was varied between 2 to 180 minutes in order to find the optimal treatment time. For Argon IIIP, the plasma exciting parameters (5Pa and 60 min) were maintained, while the radio frequency variation was between 10 to 150W. Surface energy and contact angle were obtained by and automatic goniometer, through the sessile drop method. The surface's morphology was analyzed by electronic scanning microscope and atomic force microscopy. Dispersive energy spectroscopy and X-ray photoelectric spectroscopy were responsible for the chemical composition and molecular structure analyses the new surface's resistance was tested by O2 plasma corrosion and immersed in chlorinated water. Results show the samples treated for 90,120 and 180 minutes in SF6 plasma became hydrophobic, even after aging. The samples were substantially improved and its resistance prolonged its lifespan in conventional usage. Argon IIIP made the surface more hydrophilic. However, after time part of the material restored its original characteristics. Although hydrophobic it was not achieved, the roughness and morphology alteration (especially when treated with 100W of plasma) improved COPE'S resistance. The results are explained by the increase in the structure's ability to connect by the establishment of reticulate one generated by the IIP process, making the component denser and the ionic solution less permeable.