Made available in DSpace on 2014-10-09T12:48:53Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:37Z (GMT). No. of bitstreams: 1 09665.pdf: 5199882 bytes, checksum: 82561843731e1ff278143adb437e1eeb (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T14:16:47Z No. of bitstreams: 0 / Made available in DSpace on 2015-04-10T14:16:47Z (GMT). No. of bitstreams: 0 / O desenvolvimento de nanosensores luminescentes, não tóxicos e biocompatíveis estão sendo utilizados para marcação e visualização de células em biologia celular e imunoensaios ultrassensíveis. Neste trabalho, marcadores biológicos à base de terras raras para a detecção do 17-β-estradiol (E2), em fluido biológico(plasma) foram estudados. Os complexos precursores à base de terras raras (Eu3+ e Tb3+) foram sintetizados e caracterizados. O complexo contendo tta- de Eu3+ e liganteauxiliar TOPO [Eu(tta)3(TOPO)2] registrou a maior eficiência de luminescência dentre todos os demais compostos estudados e foi escolhido como sonda luminescente para desenvolvimento das etapas seguintes deste trabalho. Este complexo foi incorporado às matrizes poliméricas, PMMA e PHB, em diferentes concentrações de dopagens pordois métodos distintos: nanoprecipitação crioscópica e pela técnica de emulsão-difusão. As nanopartículas poliméricas de PMMA demonstraram maior eficiêncialuminescente quando dopadas com concentração de 5% do complexo precursor [Eu(tta)3(TOPO)2]. Estas nanopartículas foram funcionalizadas com 1,6 hexodiamino eposteriormente foram ligadas a um dialdeído que servirá como ponte na reação comas entidades biológicas. No entanto, devido à transferência de energia do sistemaorgânico Ac-Ac/nanossensor, as nanopartículas poliméricas luminescentes de PHBdemonstraram maior intensidade de sinal para a detecção do 17-β-estradiol por espectrofluorimetria. Pode-se concluir que as nanopartículas produzidas e testadasneste trabalho são fortes candidatas para a detecção do 17-β-estradiol em plasma sanguíneo ou outras entidades biológicas, apresentando opções diagnósticas, conduta extremamente importante para direcionamento terapêutico. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Cette thèse a pour objet la mesure de déformations sans contact lors d'un essai de traction à l'aide de la méthode de corrélation d'images numériques DIC (Digital Image Correlation). Cette technologie utilise le repérage d'un motif aléatoire de tachetures pour mesurer avec précision les déplacements sur une surface donnée d'un objet subissant une déformation. Plus précisément, un algorithme DIC plus efficace a été formulé, appliqué et validé. La présente thèse comporte cinq parties consacrées au développement et à la validation du nouvel algorithme DIC: (a) la formulation mathématique et la programmation, (b) la vérification numérique, (c) la validation expérimentale, par essai de traction, en comparant les mesures DIC à celles obtenues par des jauges de déformation, (d) l'étude d'un procédé d'atomisation novateur pour générer de façon reproductible le motif de tachetures pour un repérage plus exact, et (e) l'analyse des sources d'erreur dans les mesures DIC. Plus précisément, l'algorithme DIC a servi à analyser, à titre d'exemple d'application, les propriétés mécaniques du polyméthyl métacrylate utilisé pour la reconstruction du squelette. Avec l'algorithme DIC, les images d'un objet sont acquises pendant la déformation de celui-ci. On applique ensuite des techniques d'optimisation non linéaire pour suivre le motif de tachetures à la surface des objets subissant une déformation en traction avant et après le déplacement. Ce procédé d'optimisation demande un choix de valeurs de déplacement initiales. Plus l'estimation de ces valeurs de déplacement initiales est juste, plus il y a de chances que la convergence du processus d'optimisation soit efficace. Ainsi, cette thèse présente une technique de traitement novatrice reposant sur une logique floue incluant aussi l'approximation des valeurs initiales du déplacement pour démarrer un processus itératif d'optimisation, ayant pour résultat une reproduction plus exacte et efficace des déplacements et des déformations. La formulation mathématique du nouvel algorithme a été développée et ensuite mise en œuvre avec succès dans le langage de programmation MATLAB. La vérification de l'algorithme a été faite à l'aide d'images de synthèse simu­lant des déplacements de corps rigides et des déformations de traction uniformes. Plus particulièrement, les images de déplacement simulaient (1) des déplacements de 0, 1 - 1 pixel en translation, (2) des angles de rotation de 0, 5 - 5°, et (3) de grandes déformations en traction de l'ordre de 5000 à 300000µE déformation, respectivement. Les processus de vérification ont démontré que le taux d'exactitude du nouvel algorithme DIC est supérieur à 99% en ce qui concerne les mesures des différents types et niveaux de déplacements simulés. Une validation expérimentale a été menée afin d'examiner l'efficacité de la nouvelle tech­nique dans des conditions réalistes. Des échantillons de PMMA normalisés, respectant la norme ASTM F3087, ont été produits, inspectés et soumis à une charge de traction jus­qu'à la rupture. La déformation de la surface des échantillons a été mesurée au moyen (a) du nouvel algorithme DIC, et (b) des techniques utilisant des jauges de déformation de type rosette. La force maximale moyenne et la limite de résistance mécanique des quatre échantillons étaient de 880 ± 110 N et 49 ± 7 MPa, respectivement. La limite moyenne de déformation mesurée par la jauge de déformation et provenant de l'algorithme DIC étaient de 15750±2570 et 19890±3790 µs déformation, respectivement. Des déformations d'un tel ordre sont courantes pour les matériaux polymériques, et jusqu'à maintenant, la technique DIC n'n’était pas développée pour faire des mesures de déformations aussi importantes. On a constaté que l'erreur relative de la mesure DIC, par rapport à la technique de la jauge de déformation, s'élevait à 26 ± 8%. Par ailleurs, le module de Young moyen et le coefficient de Poisson moyen mesurés en utilisant des jauges de déformations étaient de 3, 78 ± 0, 07 G Pa et 0, 37 ± 0, 02, alors qu'ils étaient de 3, 16 ± 0, 61 GPa et 0, 37 ± 0, 08, respectivement lorsque mesurés avec l'algorithme DIC. L'écart croissant entre les mesures de déformation DIC et celles obtenues au moyen de jauges de déformation est probablement lié à la dis­torsion graduelle du motif de tachetures à la surface des échantillons de traction. Par la suite, on a introduit un facteur de correction de 1, 27 afin de corriger l'erreur systématique dans les mesures de déformation provenant de l'algorithme DIC. La limite de déformation des mesures DIC a été rajustée à 15712±357 µs déformation avec un taux d'erreur moyen relatif de -0, 5 ± 7, 1 %, comparé aux déformations mesurées par la jauge de déformation. Le module de Young moyen et le coefficient moyen de Poisson de l'algorithme DIC et des mesures obtenues par la jauge de déformation ont par ailleurs été rajustés à 3, 8 ± 0, 4 GPa et 0, 368 ± 0, 025, respectivement. Au moyen d'un procédé d'atomisation, des taches de peinture ont été générées de façon reproductible sur la surface d'un objet. Une approche expérimentale de planification facto­rielle a été utilisée pour étudier le motif de tachetures (répartition et gradient de l'échelle des tons de gris) pour mesurer l'exactitude de l'algorithme DIC. Plus particulièrement, neuf motifs de tachetures différents ont été générés au moyen du procédé d'atomisation et testés pour la translation et la rotation de corps rigides. Les résultats ont révélé que l'erreur moyenne relative parmi les neuf motifs de tachetures variait de 1, 1 ± 0, 3% à -6, 5 ± 3, 6%. Le motif de tachetures préféré, lequel se démarquait par une large gamme de taches claires et de valeurs de tons de gris, a produit une erreur relative de 1, 1 ± 0, 3%. Une analyse des erreurs et des sources d'erreurs relatives de la mesure de l'algorithme DIC a été menée. Ti-ois catégories de sources d'erreurs, incluant l'algorithme lui-même, les paramètres du processus (taille des sous-ensembles, nombre de pixels calculés) et l'en­vironnement physique (uniformité des échantillons, motifs de tachetures, effet thermique de la caméra CCD et distorsion de la lentille, erreur de non-linéarité dans le circuit de la jauge de déformation) ont fait l'objet d'une étude et de discussions. Enfin, des solutions ont été amenées afin d'aider à réduire les erreurs systématiques et aléatoires en lien avec les trois catégories de sources d'erreurs susmentionnées. Pour terminer, un nouvel algorithme DIC permettant une approximation plus juste de l'estimation initiale, entraînant par conséquent une convergence efficace et précise de l'op­timisation a été développé, programmé, mis en oeuvre et vérifié avec succès pour ce qui est des déformations importantes. La validation expérimentale a fait ressortir une erreur systé­matique inattendue des mesures DIC lorsque comparées aux mesures obtenues au moyen de la technique des jauges de déformation. Plus l'échantillon se déformait, plus l'erreur augmentait proportionnellement. Par conséquent, la distorsion graduelle des tachetures sur la surface de l'objet était probablement la cause de l'erreur. L'erreur étant systéma­tique, elle a été corrigée. Le procédé d'atomisation a permis de générer des tachetures de façon reproductible sur la surface d'un objet. Grâce aux mesures DIC, le comportement mécanique des polymères soumis à des déformations importantes, comme le polyméthyl métacrylate servant à la reconstruction du squelette, peut être étudié et une fois maîtrisé, servir à l'élaboration de matériaux plus efficaces. / Abstract : The present thesis is focused on the non-contact and efficient strain measurement using the Digital Image Correlation (DIC) method, which employs the tracking of random speckle pattern for accurate measurement of displacements on a surface of an object undergoing deformation. Specifically, a more efficient DIC algorithm was successfully developed, implemented, and validated. This thesis consists of five parts related to the novel DIC algorithm: (a) the development and implementation, (b) the numerical verification, (c) the experimental validation, for tensile loading, by comparing to the deformation measurements using the strain gauge technique, (d) the investigation of a novel atomization process to reproducibly generate the speckle pattern for accurate tracking, and (e) the analysis of the error sources in the DIC measurements. Specifically, the DIC algorithm was used to exemplarily examine the mechanical properties of polymethyl methacrylate (PMMA) used in skeletal reconstruction. In the DIC algorithm, images of an object are captured as it deforms. Nonlinear optimization techniques are then used to correlate the speckle on the surface of the objects before and after the displacement. This optimization process includes a choice of suitable initial displacement values. The more accurate the estimation of these initial displacement values are, the more likely and the more efficient the convergence of the optimization process is. The thesis introduced a novel, fuzzy logics based processing technique, approximation of the initial values of the displacement for initializing iterative optimization, which more accurately and efficiently renders the displacements and deformations as results. The mathematical formulation of the novel algorithm was developed and then successfully implemented into MATLAB programming language. The algorithmic verification was performed using computer-generated images simulating rigid body displacements and uniform tensile deformations. Specifically, the rigid motion images simulated (1) displacements of 0.1-1 pixel for the rigid body translation, (2) rotation angles of 0.5-5 ̊ for rigid body rotation and (3) large tensile deformations of 5000-300000µɛ, respectively. The verification processes showed that the accuracy of the novel DIC algorithm, for the simulated displacement types and levels above 99%. The experimental validation was conducted to examine the effectiveness of the novel technique under realistic testing conditions. Normalized PMMA specimens, in accordance to ASTM F3087, were produced, inspected and subjected to tensile loading until failure. The deformation of the specimen surface was measured using (a) the novel DIC, and (b) strain gauge rosette techniques. The mean maximum force and ultimate strength of four specimens were 882.2±108.3 N and 49.3±6.2 MPa, respectively. The mean ultimate deformation from the gauge and DIC groups were 15746±2567µɛ and 19887±3790µɛ, respectively. These large deformations are common in polymeric materials, and the DIC technique has thus far not been investigated for large deformation. The relative mean error of the DIC measurement, in reference to those of the strain gauge technique, was found to be up to 26.0±7.1%. Accordingly, the mean Young's modulus and Poisson's ratio of strain gauge measurement were 3.78±0.07 GPa and 0.374±0.02, and of the DIC measurements were 3.16±0.61 GPa and 0.373±0.08, respectively. The increasing difference of the DIC strain measurements relative to those of the strain gauge technique is likely related to the gradual distortion of the speckle pattern on the surface of the tensile specimen. Subsequently, a Correction Factor (CF) of 1.27 was introduced to correct for the systematic error in the deformation measurements of the DIC group. The corrected ultimate deformation of the DIC measurements became 15712±357µɛ with the relative mean error of -0.5±7.1%, if compared to those measurements of the strain gauge techniques. Correspondingly, the mean Young's Modulus and Poisson's ratio of the DIC and of the strain gauge measurements became 3.8±0.4 GPa and 0.368±0.025, respectively. Using an atomization process, paint speckles were reproducibly generated on the surface of an object. A factorial design of experiments was used to investigate the speckle pattern (grey value distribution and gradient) for the DIC measurement accuracy. Specifically, nine different speckle patterns were generated using the atomization process and tested for rigid body translation and rotation. The results showed the relative mean errors among the nine speckle patterns varied from 1.1±0.3% to -6.5±3.6%. The preferred speckle pattern, which was characterized by a wide range of sharp speckle and of grey values, produced a mean error of 1.1±0.3%. The analysis of errors and relating sources in the DIC measurement was conducted. Three categories of sources including algorithmic sources, processing parameters sources (subset size, number of pixels computed) and physical environment sources (specimen uniformity, speckle pattern, self-heating effect of the CCD camera and lens distortion of the camera, non-linearity error in strain gauge circuit) were investigated and discussed. Finally, the solutions were provided in order to help reduce the systematic and random errors relating to the aforementioned three categories of sources for errors. In conclusion, a novel DIC algorithm for a more accurate approximation of the initial guess and accordingly for an efficient and accurate convergence of the optimization was successfully formulated, developed, implemented and verified for relatively large deformations. The experimental validation surprisingly showed a systematic error of the DIC measurements, if compared to the measurements of the strain gauge technique. The larger the deformation applied to the specimen, the larger the error gradually became. Therefore, the gradual distortion of the speckles on the surface of the object was likely the underlying cause of the error. The error was systematic and therefore corrected. The atomization process allowed generating reproducible speckles on the surface of an object. Using the DIC measurements, the mechanical behavior of polymers, undergoing large deformations, such as polymethyl methacrylate used in skeletal reconstruction can be investigated and, once understood, the knowledge gained can help develop more effective materials.

La conception de matériaux aux propriétés mécaniques caractéristiques de polymères à la température d'usage, mais capables de s'écouler comme des liquides simples lorsqu'ils sont chauffés demeure l'un des défis les plus importants de la chimie supramoléculaire. La combinaison de ces propriétés antagonistes est hautement souhaitable afin d'assurer au matériau durabilité, malléabilité, et recyclabilité. Ici, nous explorons une nouvelle stratégie basée sur des réactions de polycondensation, dans le but de concevoir des matériaux polymères supramoléculaires avec une contrainte à la rupture supérieure à 10 MPa et une viscosité en fondu inférieur à 1 Pa.s. Nous décrivons notamment la synthèse et les propriétés rhéologiques et mécaniques (essais de traction uniaxiale) de polymères supramoléculaires basés sur une architecture de type polyamide multibloc. La flexibilité des réactions de polycondensation permet de contrôler la distribution de la taille des chaînes. L'établissement de liaisons hydrogène et la cristallisation des groupements associatifs aux extrémités de chaînes et des segments cristallisables en milieux de chaînes permettent d'atteindre les propriétés ciblées. Une seconde famille de polymères supramoléculaires, basée sur un squelette de PMMA, a été synthétisée par polymérisation radicalaire contrôlée (ATRP ou RAFT). Cette dernière permet un contrôle précis des masses moléculaires, et la modification chimique des oligomères post-polymérisation permet d'obtenir des chaînes de PMMA supramoléculaires terminées aux deux extrémités par des groupements associatifs. Les propriétés thermiques, mécaniques et rhéologiques de ce polymère supramoléculaire sont décrites. / Design of materials with polymer-like properties at service temperature but able to flow like simple liquids when heated remains one of the important challenges of supramolecular chemistry. Combining these antagonistic properties is highly desirable to provide durability, processability, and recyclability of materials. Here, we explore a new strategy based on polycondensation reactions to design supramolecular polymer materials with stress at break above 10 MPa and melt viscosity lower than 1 Pa·s. We describe the synthesis and rheological and mechanical properties (uniaxial tensile tests) of supramolecular polymers based on a multiblock polyamide architecture. The flexibility of polycondensation reactions made it possible to control the molecular size distribution, the strength of hydrogen bonds, and the crystallization of middle and end groups and to achieve targeted properties. A second family of supramolecular polymers, based on a PMMA backbone, was designed and synthesized by ATRP or RAFT polymerization. Controlled radical polymerization enabled precise control over molecular weight and chemical modification of the oligomers allowed us to obtain supramolecular PMMA terminated at both ends by associative groups. Thermal, mechanical and rheological properties of this supramolecular polymer are described.

The effect of hydrogen bonding interactions on the drop generation of both acid and hydroxyl-containing polymer solutions is reported showing that polymer chain relaxation can be influenced through the use of appropriate polymer co-solvent interactions for polymers having weight average molecular weight (Mw) < 100 kDa. Reported for the first time is evidence of flow-induced polymer degradation during inkjet printing for both poly(methylmethacrylate) and polystyrene in good solvent. Polymers having Mw either less than 100 kDa or greater than approximately 1,000 kDa show no evidence of molecular weight degradation. The lower boundary condition is a consequence of low Deborah number imposed by the printhead geometry and the upper boundary condition due to viscoelastic damping. For intermediate molecular weights the effect is greatest at high elongational strain rate and low solution concentration with higher polydispersity polymers being most sensitive to molecular weight degradation. For low polydispersity samples, PDi £ 1.3 chain breakage is essentially centro-symmetric induced either by overstretching when the strain rate increases well beyond a critical value, that is the stretching rate is high enough to exceed the rate of relaxation or by turbulence. For higher polydispersity samples, PDi chain breakage is consistent with almost random scission along the chain inferring that the forces required to break the chain are additionally transmitted either by valence bonds, i.e. network chains and junctions or discrete entanglements rather than solely by hydrodynamic interaction. Preliminary results are presented on the degradation of molecular structure in water of two galactomannan’s in water after inkjet printing. Galactommann’s are known to form complex H-bonded structures in water and the results are consistent with breaking of the H-bonding structure at low reduced concentration with evidence of main chain breakage at higher reduced concentration, c/c* = 0.25.

Orientador: Peter Hammer / Resumo: Este trabalho relata uma investigação detalhada das propriedades estruturais e eletroquímicas de revestimentos de polimetilmetacrilato (PMMA)-sílica. Espectroscopia Raman e análise térmica mostraram que o ajuste da quantidade de peróxido de benzoíla (BPO), como um parâmetro crítico de síntese, melhora a eficiência de polimerização do metilmetacrilato (MMA), levando a uma estrutura híbrida altamente reticulada. A espectroscopia de impedância eletroquímica (EIS) mostrou para revestimentos depositados sobre aço carbono (A1020) e liga de Al (AA7075) uma resposta de impedância capacitiva quase ideal, mantendo o módulo de impedância de baixa frequência de até 10 GΩ cm2 essencialmente inalterado durante 19 meses de imersão em NaCl 3,5%. Embora revestimentos passivos de alto desempenho tenham sido desenvolvidos, pites de corrosão podem afetar significativamente sua durabilidade. Assim, a inibição da corrosão ativa induzida por íons lítio e cério em revestimentos de sílica sol-gel de PMMA foi investigada. A adição de carbonato de lítio produziu revestimentos com melhor conectividade dos nós de sílica nanométricos e forte adesão ao substrato de alumínio. Os resultados de EIS mostraram que as concentrações de lítio mais altas resultam em um aumento no módulo de impedância e induzem a autorregeneração que aumenta significativamente sua vida útil dos revestimentos. Time-of-flight secondary ion mass spectrometry (ToFSIMS) e a espectroscopia de fotoelétrons excitados por raios-X (XPS) suger... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work reports on a detailed investigation of the structural and electrochemical properties of poly(methyl methacrylate) (PMMA)-silica coatings. Raman spectroscopy and thermal analysis showed that the fine-tuning of the benzoyl peroxide (BPO) amount, as a critical synthesis parameter, improves the polymerization efficiency of methyl methacrylate (MMA), leading to a highly cross-linked hybrid structure. Electrochemical impedance spectroscopy (EIS) showed for coatings deposited on carbon steel (A1020) and Al alloy (AA7075) a quasi-ideal capacitive impedance response, maintaining the low frequency impedance modulus of up to 10 GΩ cm2 essentially unchanged during 19 months of immersion in 3.5% NaCl. Although high performance passive coatings have been developed, pitting can significantly affect their durability. Hence, active corrosion inhibition induced by lithium and cerium ions in PMMA-silica sol-gel coatings was investigated. The addition of lithium carbonate yielded coatings with improved connectivity of nanometric silica cross-link nodes and stronger adhesion to the aluminum substrate. EIS results showed that higher lithium concentrations result in an increased impedance modulus and induce the self-healing ability, extending significantly the service life of the coatings. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and X-ray photoelectron spectroscopy (XPS) suggest that the regeneration process occurs by means of lithium ions leaching from the adjacent coat... (Complete abstract click electronic access below) / Doutor

Ever since their discovery, Carbon nanotubes (CNTs) have been renowned to be potential candidates for a variety of applications. Nevertheless, the difficulties accompanied with their dispersion and poor solubility in various solvents have hindered CNTs potential applications. As a result, studies have been developed to address the dispersion problem. The solution is in modifying the surfaces of the nanotubes covalently or non-covalently with a desired dispersant. Various materials have been employed for this purpose out of which polymers are the most common. Non-covalent functionalization of CNTs via polymer wrapping represents an attractive method to obtain a stable and homogenous CNTs dispersion. This method is able to change the surface properties of the nanotubes without destroying their intrinsic structure and preserving their properties. This thesis explores and studies the surface modification and solublization of pristine single and multiwalled carbon nanotubes via a simple solution mixing technique through non-covalent interactions of CNTs with various anionic and cationic conjugated polyelectrolytes (CPEs). The work includes studying the interaction of various poly(phenylene ethynylene) electrolytes with MWCNTs and an imidazolium functionalized poly(3-hexylthiophene) with SWCNTs. Our work here focuses on the noncovalent modifications of carbon nanotubes using novel CPEs in order to use these resulting CPE/CNT complexes in various applications. Upon modifying the CNTs with the CPEs, the resulting CPE/CNT complex has been proven to be easily dispersed in various organic and aqueous solution with excellent homogeneity and stability for several months. This complex was then used as a nanofiller and was dispersed in another polymer matrix (poly(methyl methacrylate), PMMA). The PMMA/CPE/CNT composite materials were cast or electrospun depending on their desired application. The presence of the CPE modified CNTs in the polymer matrix has been proven to enhance the composites thermal, mechanical and electrical properties compared to pristine CNTs. Various spectroscopic and microscopic techniques such as UV-vis, fluorescence, TEM, AFM and SEM were used to study and characterize the CPE/CNT complexes. Also, TGA, DSC and DMA were used to study the thermal and mechanical properties of the composite materials. Our current work represents a fundamental study on the non-covalent interactions between CNTs and CPEs on one hand and gives a real life example on the CPE/CNT application in composite materials and electronics.

Electrospinning is a useful technique that can generate micro- and nano-meter sized fibers from polymer materials. Modification of the electrospinning parameters and apparatus can generate nanofibers for use in diverse applications ranging from tissue engineering to nanocomposite fabrication; however, electrospun fibers are typically collected in a random orientation and over large areas limiting their applications.  Here we present several methods to control the deposition of electrospun nanofibers, such as the use of a single auxiliary electrode ring and a negatively charged collector substrate to control the deposition area and the construction of a parallel electrode collector known as the triple electrode setup to control the uniaxial alignment of nanofibers. The numerous constructed setups were advanced by the use of electric field computations to assess the distribution of the electric field and its effect on the deposition behavior and morphology of the electrospun nanofibers. The electrostatic force imposed by the auxiliary electrodes provides converged electric fields that direct the nanofibers to their desired deposition targets. Here it is shown that the use of the auxiliary electrode ring dramatically decreased the deposition area of nanofibers, the negatively charged substrate yielded more uniform nanofibers and the triple electrode setup is a viable method to achieve uniaxially aligned nanofiber mats.    The electrospinning of copolymers appears as an attractive option for enhancing the overall properties of nanofibers as it offers possibility of an intrinsic control of the polymeric material itself. The poly(methyl methacrylate)-graft-poly(dimethylsiloxane) graft copolymer  (PMMA-g-PDMS) is considered to be an organic-inorganic hybrid material with much potential in its use in nanocomposites, and in this work has been successfully synthesized and electrospun via the various constructed electrospinning setups.   In the final elements of this work, the triple electrode setup is used in combination with a dynamic rotating collector to yield a novel collector and has been successfully used to produce PMMA-g-PDMS nanofiber sheets that were further incorporated in a PDMS matrix to yield nanocomposite sheets. A variant of the triple electrode setup with partially insulated electrodes is devised in combination with a methodology to remove the nanofibers from the collector. The nanofibers once removed and dried were incorporated in a PDMS matrix to yield nanocomposites. The preferential dissolution of the fibers from the matrix rendered the fibers to templates and a final porous material with uniaxial nanochannels could be obtained.   This work is believed to be able to lead to a better understanding of the mechanisms of nanofiber deposition and alignment, and should be of help to the design of more practical collecting structures, hence promoting the applications of the electrospinning technique.

This diploma thesis focuses on the design of a coffee table, which is further designated for custom-made or mass production and sale. The thesis is divided into theoretical and practical part. The theoretical part serves as a basis for the practical part as it documents the history of coffee tables and the research of coffee tables in the current market. The practical part presents the actual design process of the particular coffee table starting from the idea, first sketches, the selection of the materials and construction to the visualization of the product, the technical drawing and the budget for the production. This part also takes into account the observations from the theoretical part and tries to apply them in the design.