Cette thèse s'inscrit dans un contexte de recherche d'amélioration des propriétés d'extraction d'ions sur phase solide. Au travers de ces travaux est développée une méthodologie innovante visant à adapter la structuration, la morphologie ainsi que les fonctions d'extraction aux ions et aux milieux cibles. Pour cela, nous avons opté pour une méthode « tout-en-un » passant par l'utilisation d'organosilanes amphiphiles. Composées d'une tête condensable et d'une tête « extractante » aux extrémités d'une chaîne hydrophobe, ces molécules polyvalentes font office à la fois d'agent matriciel silicique, d'agent structurant et d'agent extractant. Par analogie avec un tensioactif, nous avons montré que l'auto-assemblage de telles molécules est gouverné par des paramètres liés notamment à la taille de la partie hydrophile de la molécule. En utilisant différents agents de courbure, il est possible de jouer sur la taille du couple agent de courbure/fonction extractante. La courbure à l'interface entre le milieu et l'agrégat est donc ajustable, ce qui conduit à différents types d'agrégation. Par cette méthode, des bicouches, des vésicules et des micelles directes cylindriques ont été obtenues. A l'inverse, l'ajout de précurseur de silice (TEOS) dans la préparation peut conduire au gonflement des structures et à l'inversion de l'agrégation vers des micelles inverses cylindriques. L'effet du solvant a également été étudié et a permis d'aboutir à des morphologies très diverses. Enfin, l'accessibilité des fonctions et les propriétés d'extraction des matériaux élaborés ont été évaluées au travers de modifications chimiques de la tête extractante et de tests d'extraction d'ions métalliques (Terres rares, platinoïdes …). / The aim of this study is to develop a suitable “all-in-one” approach involving amphiphilic organosilane precursors in order to prepare hybrid materials for solid phase extraction processes. Such molecules combine both condensable and functional parts around a long hydrophobic alkyl chain.Similarly to a surfactant, the amphiphilic behavior of the organosilane molecules is governed by the size of the hydrophilic extractant function. By playing with the curvature agent size, it is possible to adjust the size of the couple extractant part/curvature agent at the interface between the aggregates and the surrounding media. Therefore, the aggregation shape is tunable. This approach constitutes an efficient and original method in order to tune the nanostructure of highly functionalized silica at the early stage of the elaboration. Hybrid organic-inorganic planar objects and vesicles are obtained for smaller curvature agents. Increasing the size of the curvature agent results in a transition of the aggregation geometry from vesicles to cylindrical direct micelles, leading to highly functionalized nanofibers.Comparatively, the addition of a silica precursor as TEOS in the preparation results in the swelling of the condensable part of the amphiphilic organosilane molecules. Thereby, as a curvature agent, the addition of TEOS allows tuning the aggregation towards reverse cylindrical micelles. Solvent effects have also been evaluated, appearing as a critical morphological parameter. Macroporous materials, blackberry-like particles and elongated or spherical nanoparticles can be obtained depending on the solvent.Finally, the accessibility of the functions and the extraction properties of the materials have been studied through chemical modifications and metallic ion extraction experiments (Rare earth elements, platinoids …).

The synthesis of dipyridyl functionalized polysulfones with improved hydrophilicity, enhanced membrane morphology and excellent ATRP polymeric ligand properties was conducted by the following method: (a) the formation of lithiated polysulfone from unmodified polysulfone and the subsequent reaction with 2,2'-vinylidenedipyridine in tetrahydrofuran at -78 oC under argon atmosphere to afford the corresponding dipyridyl functionalized polysulfone. The stoichiometry of the reaction affects the degree of functionalization of the product. When equimolar amounts of 2,2'-vinylidenedipyridine are added to the lithiated polysulfone, the degree of functionalization obtained was 45%. However, the addition of 10% and 20% molar excess of 2,2'-vinylidenedipyridine to the corresponding lithiated polysulfone produced dipyridyl functionalized polysulfones with degrees of functionalization of 80% and 95%, respectively; and (b) the membranes obtained from unmodified polysulfone as well as dipyridyl functionalized polysulfones were characterized by atomic force microscopy, scanning electron microscopy, pure water permeation measurements and contact angle measurements. Amine chain end functionalized polystyrene and poly(methyl methacrylate) were prepared by Atom Transfer Radical Polymerization (ATRP) methods as follows: (a) •-Aminophenyl functionalized polystyrene was prepared in quantitative yields by ATRP methods using a new primary amine functionalized initiator adduct, formed in situ by the reaction of 1-(4-aminophenyl)-1-phenylethylene and (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst in diethyl ether at 110 oC, for the polymerization of styrene.(b) New •-bis(aminophenyl) and •,ω-tetrakis(aminophenyl) functionalized polymers were prepared in quantitative yields by the ATRP method using the following synthetic strategy: (i) the initiation of styrene polymerization with a new primary diamine functionalized initiator adduct, generated in situ by the reaction of stoichiometric amounts of 1,1-bis(4-aminophenyl)ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as catalyst, afforded •-bis(aminophenyl) functionalized polystyrene; and (ii) •-bis(aminophenyl) functionalized poly(methyl methacrylate) was prepared by the ATRP method using the primary diamine functionalized initiator adduct as initiator for methyl methacrylate polymerization; and (iii) well defined •,ω-tetrakis(aminophenyl) functionalized polystyrene was prepared by the post ATRP chain end modification reaction of •-bis(aminophenyl) functionalized polystyrene with 1,1-bis(4-aminophenyl)-ethylene at the completion of the polymerization reaction. (c) Similarly, •-bis(4-dimethylaminophenyl) functionalized polystyrene was prepared by using a new tertiary diamine functionalized initiator adduct, formed in situ by treatment of equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]-ethylene with (1-bromoethyl)benzene in the presence of copper (I) bromide/2,2'-bipyridyl as the catalyst in diphenyl ether at 110 oC for the initiation of styrene polymerization by the ATRP method. Furthermore, the ATRP of methyl methacrylate, initiated by the new tertiary diamine functionalized initiator adduct, produced •-bis(4-dimethylaminophenyl) functionalized poly(methyl methacrylate). In addition, •,ω-tetrakis(4-dimethylaminophenyl) functionalized polystyrene was synthesized via a post ATRP chain end modification reaction of •-bis(4-dimethylaminophenyl) functionalized polystyrene with equimolar amounts of 1,1-bis[(4-dimethylamino)phenyl]ethylene at the completion of the polymerization process. vi Quantitative yields of the different amine functionalized polymers with predictable number average molecular weights (Mn = 1.3 x 103 – 16.4 x103 g/mol), narrow molecular weight distributions (Mw/Mn = 1.03 – 1.29) and controlled chain end functionality were obtained. Polymerization kinetics data was employed to determine the controlled/living character of each ATRP reaction leading to the formation of the different amine chain end functionalized polymers. The polymerization processes were monitored by gas chromatographic analyses. Polymerization kinetics measurements for all reactions show that the polymerizations follow first order rate kinetics with respect to monomer consumption. The number average molecular weight of the amine functionalized polymers increases linearly with percentage monomer conversion and polymers with narrow molecular weight distribution were obtained. The ATRP of styrene, catalyzed by a novel dipyridyl functionalized polysulfone/CuBr supported catalyst system, afforded well defined polystyrene with predictable number average molecular weight and narrow molecular weight distribution in a controlled/living free radical polymerization process. The substituted 1,1-diphenylethylene initiator precursor derivatives and the functionalized polymers were characterized by nuclear magnetic resonance spectrometry, fourier transform infrared spectroscopy, thin layer chromatography, column chromatography, size exclusion chromatography, non-aqueous titrations, differential scanning calorimetry and thermogravimetrical analysis. / Chemistry / M. Sc. (Chemistry)

Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2014-09-17T17:51:04Z No. of bitstreams: 1 (Dissertação_mestrado__(03.11_)).pdf: 1756144 bytes, checksum: 6a5c8a2f486f154eba91b5aa9780dde0 (MD5) / Approved for entry into archive by Fatima Cleômenis Botelho Maria (botelho@ufba.br) on 2014-09-19T12:24:04Z (GMT) No. of bitstreams: 1 (Dissertação_mestrado__(03.11_)).pdf: 1756144 bytes, checksum: 6a5c8a2f486f154eba91b5aa9780dde0 (MD5) / Made available in DSpace on 2014-09-19T12:24:04Z (GMT). No. of bitstreams: 1 (Dissertação_mestrado__(03.11_)).pdf: 1756144 bytes, checksum: 6a5c8a2f486f154eba91b5aa9780dde0 (MD5) / CNPQ / A determinação de metais em águas naturais por Espectrometria de Emissão Óptica com Plasma Indutivamente Acoplado (ICP OES), em geral, deve envolver etapas de pré- concentração, devido os níveis de concentração dos metais em água serem muitas vezes abaixo dos limites de detecção da técnica. Dessa forma, o objetivo desse trabalho foi desenvolver um método de pré-concentração em fase sólida sensível e simples para a determinação de cobre, ferro, níquel, manganês, chumbo e zinco em amostras de água por ICP OES. As condições experimentais para pré-concentração foram otimizadas considerando os fatores: concentração do eluente, volume de eluente, volume da amostra, vazão e pH. As condições otimizadas corresponderam ao uso de 5 mL de solução de HCl 0,8 mol L-1 como eluente, volume da amostra de 50 mL, vazão de 1,9 mL min-1 e pH 9,0. Para a determinação dos metais, as amostras, após ajuste do pH, foram percoladas com o auxílio de uma bomba peristáltica em cartucho Sep-pak C18 com 1-(2-piridilazo)-2-naftol (PAN) imobilizado na sílica funcionalizada C18. A eluição dos analitos foi realizada com a passagem da solução de HCl pelo cartucho para posterior determinação por ICP OES. Nestas condições, os limites de detecção para Cu, Fe, Mn, Ni, Pb e Zn obtidos variaram entre 0,11 e 21 µg L-1 e os limites de quantificação entre 0,36-69 µg L-1, respectivamente. Os desvios padrão relativos (R.S.D.) para a determinação dos analitos não ultrapassaram 9 %. O efeito de possíveis espécies interferentes sobre a recuperação dos analitos também foram investigados. A exatidão do método foi avaliada mediante análise de material de referência certificado (SLEW-3 Estuariene Water Reference Material for Trace Metals) e o método proposto foi aplicado para análise de amostras de água subterrânea, água potável e água de rio coletadas nos municípios de Cachoeira e São Félix, Bahia, Brasil. As amostras foram analisadas por Espectrometria de Massas com Plasma Indutivamente Acoplado (ICP-MS) como método comparativo, não sendo observadas diferenças significativas entre estes resultados e os resultados obtidos pelo método proposto. / The determination of metals in natural waters by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES), in general, involves pre-concentration steps, due the concentration levels of metals in water are often below the limits of detection of this technique. In this way, the objective of this work was to develop a pre-concentration solid phase method for sensitive and simple determination of copper, iron, nickel, manganese, lead and zinc in water samples by ICP OES. The experimental conditions for pre- concentration were optimized considering the following factors: the concentration of the eluent, eluent volume, sample volume, flow-rate and pH. The optimized conditions corresponded to the use of 5 mL of HCl solution 0.8 mol L-1 as an eluent sample volume 50 ml, flow-rate 1.9 mL min-1 and pH 9.0. For the determination of metals by the procedure, the samples after pH adjustment were percolated with the aid of a peristaltic pump on Sep-Pak C18 cartridge with 1-(2-pyridylazo)-2-naphthol (PAN). The analyte elution was carried out with the passage of the HCl solution in the cartridge for subsequent determination by ICP OES. In these conditions, the detection limit for Cu, Fe, Mn, Ni, Pb and Zn varied between 0.11 to 21 μg L-1 and the limits of quantification from 0.36 to 69 μg L-1, respectively. The relative standard deviation (RSD) for the analytes of this study did not exceed 9%. The effect of possible interfering species on the recovery of the analytes was also investigated. The accuracy of the method was evaluated by analysis of certified reference material (SLEW-3 Estuariene Water Reference Material for Trace Metals) and the proposed method was applied to samples of ground water, drinking water and river water collected in Cachoeira and São Félix cities, Bahia, Brazil. The samples were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) as a comparative method do not being found significant differences among these results and the results obtained by the proposed method.

Les cages moléculaires covalentes ou de coordination sont des molécules particulièrement intéressantes lorsqu’elles présentent une cavité active en reconnaissance moléculaire ou en réactivité chimique. Le projet consiste en la synthèse et l’étude d’un nouveau type de cage moléculaire, constituée de deux porphyrines reliées par des liaisons covalentes mais flexibles et de huit ligands 3-pyridyles (L) permettant de contrôler la taille de la cavité par un stimulus externe. L’étape-clé de la synthèse de cette cage est la formation d’un dimère de porphyrine par effet template, de sorte à favoriser la fermeture de la cage. Des cations métalliques coordinés par les groupements L ou un ligand ditopique comme le DABCO coordiné entre les métallo-porphyrines ont été utilisés pour pré-assembler le dimère. Ce dernier ayant été obtenu, les chaînes polyéther ont été reliées deux par deux par métathèse des oléfines. Une structure cristallographique de la cage covalente complexant le DABCO a pu être obtenue. La cage synthétisée a, par la suite, été démétallée et le DABCO retiré, la conformation adoptée par cette dernière molécule varie par rapport à son précurseur. / Covalent or coordination molecular cages are particularly interesting molecules when they incorporate an active cavity in molecular recognition or in chemical reactivity. The project consists in the synthesis and the study of a new type of molecular cage, built from two porphyrins linked together by covalent but flexible bonds and eight 3-pyridyl ligands (L) allowing a control of the size of the cavity by an external signal. The key-step in the cage synthesis is the formation of a template dimer in order to favour the covalent cage closing. Several metallic cations coordinated by the L moieties or a ditopic ligand such as DABCO coordinated between two metalloporphyrins have been used for the preorganization of a dimer. Once the latter compound formed, the polyether chains have been linked two-by-two by alkene metathesis. A crystallographic structure of the covalent cage complexing the DABCO has been obtained. Furthermore, the synthesized cage was demetallated and the DABCO removed, the conformation adopted by this molecule doesn’t change a lot from its precursor.

Na busca de um melhor entendimento das propriedades eletrônicas e magnéticas dos isolantes topológicos nos deparamos com uma das suas caraterísticas mais marcantes, a existência de estados de superfície metálicos com textura helicoidal de spin os quais são protegidos de impurezas não magnéticas. Na superfície estes canais de spin possuem um potencial enorme para aplicações em dispositivos spintrônicos. Muito há para se fazer e o tratamento via cálculos de primeiros princípios por simulações permite um caráter preditivo que corrobora na elucidação de fenômenos físicos via análises experimentais. Nesse trabalho analisamos as propriedades eletrônicas de isolantes topológicos tais como: (Bi,Sb)$_2$(Te,Se)$_3$, Germaneno e Germaneno funcionalizado. Cálculos baseados em DFT evidenciam a importância das separações entre as camadas de Van der Waals nos materiais Bi$_2$Se$_3$ e Bi$_2$Te$_3$. Mostramos que devido a falhas de empilhamento, pequenas oscilações no eixo de QLs (\\textit{Quintuple Layers}) podem gerar um desacoplamento dos cones de Dirac, além de criar estados metálicos na fase \\textit{bulk} de Bi$_2$Te$_3$. Em se tratando do Bi$_2$Se$_3$ um estudo sistemático dos efeitos de impurezas de metais de transição foi realizado. Observamos que há quebra de degenerescência do cone de Dirac se houver magnetização em quaisquer dos eixos. Além disso se a magnetização permanecer no plano, além de uma pequena quebra de degenerescência, há um deslocamento do mesmo para outro ponto da rede recíproca. No entanto, se a magnetização apontar para fora do plano a quebra ocorre no próprio ponto $\\Gamma$, porém de maneira mais intensa. Importante enfatizar que além de mapear os sítios com suas orientações magnéticas de menor energia observamos que a quebra da degenerescência está diretamente relacionada com a geometria local da impureza. Isso proporciona imagens de STM distintas para cada sítio possível, permitindo que um experimental localize cada situação no laboratório. Estudamos ainda a transição topológica na liga (Bi$_x$Sb$_{1-x}$)$_2$Se$_3$, onde identificamos um isolante trivial e topológico para $x=0$ e $x=1$. Apesar de óbvia a existência de tal transição, detalhes importantes ainda não estão esclarecidos. Concluímos que a dopagem com impurezas não magnéticas proporciona uma boa técnica para manipulação e engenharia de cone nesta família de materiais, de forma que dependendo da faixa de dopagem podemos eliminar a condutividade que advém do \\textit{bulk}. Finalmente estudamos superfícies de Germaneno e Germaneno funcionalizado com halogênios. Usando uma funcionalização assimétrica e com a avalição do invariante topológico $Z_2$ notamos que o material Ge-I-H é um isolante topológico podendo ser aplicado na elaboração de dispositivos baseados em spin. / In the search of a better understanding of the electronic and magnetic properties of topological insulators we are faced with one of its most striking features, the existence of metallic surface states with helical spin texture which are protected from non-magnetic impurities. On the surface these spin channels allows a huge potential for applications in spintronic devices. There is much to do and treating calculations via \\textit{Ab initio} simulations allows us a predictive character that corroborates the elucidation of physical phenomena through experimental analysis. In this work we analyze the electronic properties of topological insulators such as: (Bi, Sb)$_2$(Te, Se)$_3$, Germanene and functionalized Germanene. Calculations based on DFT show the importance of the separation from interlayers of Van der Waals in materials like Bi$_2$Se$_3$ and Bi$_2$Te$_3$. We show that due to stacking faults, small oscillations in the QLs axis (\\textit{Quintuple Layers}) can generate a decoupling of the Dirac cones and create metal states in the bulk phase Bi$_2$Te$_3$. Regarding the Bi$_2$Se$_3$ a systematic study of the effects of transition metal impurities was performed. We observed that there is a degeneracy lift of the Dirac cone if there is any magnetization on any axis. If the magnetization remains in plane, we observe a small shift to another reciprocal lattice point. However, if the magnetization is pointing out of the plane a lifting in energy occurs at the very $ \\Gamma $ point, but in a more intense way. It is important to emphasize that in addition to mapping the sites with their magnetic orientations of lower energy we saw that the lifting in energy is directly related to the local geometry of the impurity. This provides distinct STM images for each possible site, allowing an experimental to locate each situation in the laboratory. We also studied the topological transition in the alloy (Bi$_x$Sb$_{1-x}$)$_ 2$Se$_3$, where we identify a trivial and topological insulator for $x = 0$ and $x = 1$. Despite the obvious existence of such a transition, important details remain unclear. We conclude that doping with non-magnetic impurities provides a good technique for handling and cone engineering this family of materials so that depending on the range of doping we can eliminate conductivity channels coming from the bulk. Finally we studied a Germanene and functionalized Germanene with halogens. Using an asymmetrical functionalization and with the topological invariant $Z_2$ we noted that the Ge-I-H system is a topological insulator that could be applied in the development of spin-based devices.

This thesis deals with the research work carried out for the development of novel applications by integrating biomolecules with various nanostructures. The thesis is organized as follows: Chapter 1 reviews the properties of nanomaterials which are important to consider while developing them for various biological and other applications. It discusses the factors which affect the cytotoxicity of nanocrystals towards living cells, photocatalytic mechanisms of nanocrystals that work behind the inactivation of bacterial cells and gas sensing properties of nanocrystals. It also mentions about the integration of biomolecules with nanomaterials which is useful for the development of biosensors, materials that are presently used for fabricating biosensors and the challenges associated with designing successful biosensors. Chapter 2 presents the antibacterial and anticancer properties of ZnO/Ag nanohybids. In this study a simple route to synthesize ZnO/Ag nanohybrids by microwave synthesis has been established where ZnO/Ag nanohybrids have shown synergistic cytotoxicity towards mammalian cells. The observed synergism in the cytotoxicity of ZnO/Ag nanohybrids could lead to the development of low dose therapeutics for cancer treatment. Chapter 3 presents photocatalytic inactivation of bacterial cells by pentavalent bismuthates class of materials. AgBiO3 which was obtained from KBiO3 by ion-exchange method was investigated for its photocatalytic inactivation properties towards E.coli and S.aureus cells under dark and UV illumination conditions. Chapter 4 presents the integration of DNA molecules with ZnO nanorods for the observation of Mott-Gurney characteristics. In this study, ZnO nanorods were synthesized hydrothermally and were characterized by TEM and XRD analysis. DNA molecules were immobilized over ZnO nanorods which were confirmed by UV-Vis spectroscopy and confocal florescence microscopy. Solution processed devices were fabricated by using these DNA immobilized nanostructures and I-V characteristics of these devices were taken in dark and under illumination conditions at different wavelengths of light at fixed intensity. Interestingly, Mott-Gurney law was observed in the I-V characteristics of the devices fabricated using DNA immobilized ZnO nanorods. Chapter 5 presents the chemical synthesis of molecular scale ultrathin Au nanowires. These nanostructures were then used for fabricating electronic biosensors. In this study, the devices were fabricated over Au nanowires by e-beam lithography and a methodology to functionalize Au nanowires and then characterize them by florescence microscopy as well as AFM has been established. The fabricated biosensors were employed for the label free, electrical detection of DNA hybridization process. Chapter 6 presents a simple, cost effective and solution processed route to fabricate devices using ultrathin Au nanowires. The devices were then used for sensing ethanol, H2 and NH3. An important property of these devices is that they can sense these gases at room temperature which reduce their operation cost and makes them desirable to use under explosive conditions.

Les matériaux composites prennent une place de plus en plus importante dans la conception et la fabrication des moyens de transport et notamment dans le domaine naval où ils sont particulièrement privilégiés. En effet, ces matériaux sont utilisés pour leur légèreté, insensibilité à la corrosion et leurs caractéristiques mécaniques. Dans le domaine militaire, où l'optimisation des moyens de communication et de protection électromagnétique est primordiale, le développement de matériaux composites dotés de propriétés de reconfigurabilité sous commande(s) externe(s), présente un atout opérationnel majeur pour les parois structurales exploitant ces matériaux. Afin d'explorer cette voie, DCNS et l'Institut d’Électronique et de Télécommunications de Rennes (IETR, UMR-6164) se sont associés. Les travaux de thèse engagés ont pour objectif d'étudier et de développer des matériaux composites présentant des fonctions de reconfigurabilité applicables aux systèmes navals tels que les radômes, les antennes et exploitables pour répondre aux problématiques de furtivité (SER). Une première étude a permis d'explorer les matériaux à base de carbone, présentant une potentielle agilité de leurs caractéristiques diélectriques sous actuateur électrique. Ces matériaux présentent également un fort pouvoir absorbant électromagnétique, tributaire des propriétés diélectriques, elles-mêmes potentiellement reconfigurables. La seconde étude engagée a étudié l'impact des matériaux ferroélectriques, c'est-à-dire des matériaux reconfigurables sous champ électrique, lorsqu'ils sont intégrés comme charge dans une résine d'imprégnation. Ce nouveau matériau composite présente alors une reconfigurabilité de ses caractéristiques diélectriques, rendant commandable en fréquence sa structure hôte. Une troisième étude, exploitant aussi le matériau ferroélectrique a permis l'obtention d'une reconfigurabilité des caractéristiques de réflectivité de panneaux composites grâce au développement de surfaces sélectives en fréquence reconfigurables. De nouvelles propriétés ont ainsi été mises en évidence en hyperfréquences. Enfin, les matériaux d'âmes et spécifiquement les nids d'abeilles diélectriques ont fait l'étude d'une fonctionnalisation pour des applications DC et hyperfréquences. / Composite materials are used for their lightness, high resistance to corrosion and high mechanical properties over large application areas, such as naval, ground and aerial. Collaboration between DCNS group and the Institute of Electronics and Telecommunications of Rennes (IETR, UMR-6164) has been initiated to develop smart composite materials with tunable properties at microwaves. Three different routes have been investigated during the thesis work. The first one is based on carbon composite material, its electromagnetic absorbing ability and its potential dielectric tunability. For this, we develop composite materials loaded with various carbon particles (carbon nanotube, graphene, black carbon). Next, to elaborate smart composite materials, a ferroelectric material has been used as filler. The dielectric characteristics of such materials can be tuned under external biasing for example. Thus we develop an active composite material under various external actuators for naval application, and especially for new reconfigurable frequency selective surface (RFSS). Finally dielectric honeycomb materials have been specifically elaborated and studied to develop smart properties for DC and microwave applications. During this work, three different prototypes improving composite materials in naval area have been performed: reconfigurable radome, RCS reduction, and antenna isolation.

Ce travail s'inscrit dans le cadre de la chimie supramoléculaire, domaine s'intéressant à l'étude d'édifices moléculaires liés par des interactions non-covalentes, fréquemment rencontrés dans le monde du vivant. Afin de mieux comprendre les phénomènes de complexation, de nombreux récepteurs moléculaires synthétiques ont été développés depuis ces cinquante dernières années. Dans le cadre de la reconnaissance moléculaire, les calix[6]arènes s'avèrent être des plateformes idéales puisqu'ils sont aisément fonctionnalisables et possèdent une cavité hydrophobe propice à l'inclusion de petites molécules organiques. D'ailleurs de nombreux récepteurs calix[6]aréniques ont déjà été développés et ont été étudiés pour leur aptitude à complexer des molécules neutres, des anions, des paires d'ions ou des ions métalliques. Cependant, ils souffrent de certaines limitations puisqu'ils ne sont pas hydrosolubles et sont difficilement post-fonctionnalisables limitant de ce fait leur applicabilité. Nous nous sommes donc intéressés à la synthèse de récepteurs calix[6]aréniques fonctionnalisés ainsi qu'à l'étude de leurs propriétés réceptrices vis-à-vis d'entités chargées ou de molécules neutres. Les études de ces systèmes ont été réalisées essentiellement par spectroscopie de Résonance Magnétique Nucléaire (RMN).<p>Dans le cadre de ce travail, des récepteurs ditopiques mono- et trisfonctionnalisés de type calix[6]cryptamide ont tout d'abord été développés. Ces récepteurs présentent un motif trenamide qui constitue un second site de reconnaissance, distinct mais proche du premier formé par la cavité calix[6]arénique. Ces récepteurs se sont révélés capables de complexer les molécules neutres polaires ainsi que des entités chargées avec une grande sélectivité en milieu aprotique mais également en présence d'un solvant protique. Le chapeau trenamide étant relativement contraint et bien préorganisé, il assure un fort effet chélate et permet une sélectivité de taille pour l'anion fluorure. La proximité des deux sites de reconnaissance ainsi que la sélectivité pour l'anion fluorure permettent à ces récepteurs de reconnaître des ammoniums sous forme de paires d'ions de contact uniquement avec le fluorure comme partenaire anionique. Les résultats obtenus ont démontré que l'introduction de fonctionnalisations soit au niveau du chapeau trenamide, à proximité du site de reconnaissance, soit au niveau du petit col du calix[6]arène n'inhibait pas les propriétés de complexation de ces récepteurs. Les premiers essais d'introduction de groupes hydrosolubilisants ont alors été réalisés et se sont révélés très prometteurs. En effet, l'introduction de groupements PEG sur un calix[6]cryptamide trisfonctionnalisé a permis de démontrer l'aptitude de ce récepteur à complexer des molécules neutres en milieu aqueux (CD3OD/D2O).<p>Dans un second temps, des récepteurs mono- et trisfonctionnalisés de type calix[6]tren ont été développés. Les études préliminaires réalisées ont permis de mettre en évidence que, comme le calix[6]tren non fonctionnalisé, ces récepteurs étaient capable de complexer de petites molécules organiques lorsqu'ils sont polarisés, soit sous leur forme per-protonnée soit sous la forme d'un complexe métallique (Zn2+ ou Cun+). <p><p>L'ensemble de ces travaux a ainsi permis de valider la stratégie de synthèse visant à introduire des bras fonctionnels sur des récepteurs ditopiques calix[6]aréniques et de démontrer que ces nouveaux récepteurs fonctionnalisés conservaient des propriétés de reconnaissance. Ces travaux permettent donc d'envisager de multiples applications pour ce type de récepteurs.<p>This work falls within the field of supramolecular chemistry, a field concerned with the study of molecular structures linked by non-covalent interactions. Such weak interactions are frequently encountered in the living world and in particular in molecular recognition processes. In order to better understand and exploit these recognition processes, many synthetic molecular receptors have been developed over the last fifty years. In this regard, calix[6]arenes have proved to be ideal platforms because they can be easily functionalized and they possess a hydrophobic cavity suitable for the inclusion of small organic molecules. Hence, many calix[6]arene based receptors have been studied for their ability to complex neutral molecules, anions, ion pairs or metal ions. However, most of these receptors suffer from major limitations that limit their applicability: they are not water soluble and hardly post-functionalizable. In the frame of this thesis, we were therefore interested in the synthesis of functionalized calix[6]arene based receptors and in the study of their host-guest properties toward charged species or neutral molecules. Studies of these host-guest systems have been carried out mainly by Nuclear Magnetic Resonance spectroscopy (NMR).<p><p>First, mono- and trisfunctionalized ditopic receptors based on a calix[6]cryptamide skeleton were synthesized. These receptors possess two binding sites in close proximity: a trenamide subunit and the calix[6]arene cavity. They have proved to be capable of complexing neutral polar molecules as well as charged species with high selectivity in aprotic solvents but also in a protic environment. The trenamide cap being relatively constrained and well pre-organized, it provides a strong chelate effect and allows a selectivity of size for the fluoride anion. Remarkably, the proximity of the two recognition sites allow these receptors to recognize ammonium ions in the form of contact ion pairs but only with a fluoride anion as the partner. The results have shown that the introduction of functionalizations at the trenamide cap or at the narrow rim of the calix[6]arene do not inhibit the complexation properties of these receptors. First attempts in order to introduce water-solubilizing groups have been undertaken and promising results have been obtained. Indeed, the introduction of PEG groups on a trisfunctionalized calix[6]cryptamide has led to a receptor able to complex neutral molecules in an aqueous environment (CD3OD/D2O).<p><p>In a second step, mono- and trisfunctionalized receptors derived from calix[6]tren have been synthesized. Preliminary studies have highlighted that, similarly to the parent calix[6]tren, these receptors are able to complex small organic molecules when they are polarized either in their per-protonated form or in the form of a metal complex (Zn2+ or Cun+).<p><p>All this work validates the synthetic strategy that consists of introducing functional arms on ditopic calix[6]arene based receptors and opens new perspectives for the elaboration and study of molecular receptors in an aqueous environment. <p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

To meet the continuously rising demand for natural resources and high-value compounds, the development of new and more efficient separation technologies is important from both an economic and environmental point of view. Moreover, the detailed knowledge of adsorption phenomena can be beneficial for the development of task-specific adsorbents for gas separation processes. However, new or supplementary measurement techniques are needed to broaden the understanding of the underlying molecular mechanisms and to characterize promising materials with a fast and reliable method. Raman spectroscopy holds the potential to advance the state-of-the-art in thermophysical property research for CCS technologies in multiple ways. It can not only be utilized for fundamental research on adsorption on quasi non-porous materials due to the possibility to monitor the composition of fluid mixtures but also for the characterization of newly developed porous adsorbents. In this context, Raman spectroscopy was explored in this work to characterize the sorption capacity of translucent porous materials and to investigate the underlying mechanisms that govern sorption processes.:1 Introduction 2 Motivation 3 Experimental Background 4 Adsorption on Quasi Non-Porous Materials 5 Adsorption on Translucent Porous Materials 6 Gas Solubility in Liquids 7 Conclusion and Outlook 8 References Appendix: A Determined Peak Intensities for Adsorption Measurements B Determined Peak Intensities for Solubility Measurements C Results for Absorption Measurements D Results for Solubility Measurements E Propagation of Error / Um den ständig steigenden Bedarf an natürlichen Ressourcen und hochwertigen Verbindungen zu decken, ist die Entwicklung neuer und effizienterer Trenntechnologien sowohl aus wirtschaftlicher als auch aus ökologischer Sicht wichtig. Darüber hinaus kann die detaillierte Kenntnis von Adsorptionsphänomenen für die Entwicklung aufgabenspezifischer Adsorbentien für Gastrennverfahren von Nutzen sein. Es werden jedoch neue oder ergänzende Messverfahren benötigt, um das Verständnis der zugrunde liegenden molekularen Mechanismen zu erweitern und vielversprechende Materialien mit einer schnellen und zuverlässigen Methode zu charakterisieren. Die Raman Spektroskopie hat das Potenzial, den aktuellen Stand der Technik bei der Erforschung thermophysikalischer Eigenschaften für CCS-Technologien in mehrfacher Hinsicht zu verbessern. Sie kann nicht nur für die Grundlagenforschung zur Adsorption an quasi nicht-porösen Materialien genutzt werden, da mit ihr Zusammensetzung von Fluidgemischen bestimmt werden kann, sondern auch für die Charakterisierung neu entwickelter poröser Adsorptionsmittel. In diesem Kontext wurde die Raman-Spektroskopie in dieser Arbeit eingesetzt, um die Sorptionskapazität von transluzenten porösen Materialien zu charakterisieren und die zugrundeliegenden Mechanismen zu untersuchen, welche die Sorptionsprozesse steuern.:1 Introduction 2 Motivation 3 Experimental Background 4 Adsorption on Quasi Non-Porous Materials 5 Adsorption on Translucent Porous Materials 6 Gas Solubility in Liquids 7 Conclusion and Outlook 8 References Appendix: A Determined Peak Intensities for Adsorption Measurements B Determined Peak Intensities for Solubility Measurements C Results for Absorption Measurements D Results for Solubility Measurements E Propagation of Error

<div>The link between volatile organic compounds (VOCs) from breath and various diseases and specific conditions has been identified since long by the researchers. Canine studies and breath sample analysis on Gas chromatography/ Mass Spectroscopy has proven that there are VOCs in the breath that can detect and potentially predict hypoglycemia. This project aims at developing a smart nanosensor system to detect hypoglycemia from human breath. The sensor system comprises of 1-Mercapto-(triethylene glycol) methyl ether functionalized goldnanoparticle (EGNPs) sensors coated with polyetherimide (PEI) and poly(vinylidene fluoride -hexafluoropropylene) (PVDF-HFP) and polymer composite sensor made from PVDF-HFP-Carbon Black (PVDF-HFP/CB), an interface circuit that performs signal conditioning and amplification, and a microcontroller with Bluetooth Low Energy (BLE) to control the interface circuit and communicate with an external personal digital assistant. The sensors were fabricated and tested with 5 VOCs in dry air and simulated breath (mixture of air, small portion of acetone, ethanol at high humidity) to investigate sensitivity and selectivity. The name of the VOCs is not disclosed herein but these VOCs have been identified in breath and are identified as potential biomarkers for other diseases as well. </div><div> </div><div> The sensor hydrophobicity has been studied using contact angle measurement. The GNPs size was verified using Ultra-Violent-Visible (UV-VIS) Spectroscopy. Field Emission Scanning Electron Microscope (FESEM) image is used to show GNPs embedded in the polymer film. The sensors sensitivity increases by more than 400% in an environment with relative humidity (RH) of 93% and the sensors show selectivity towards VOCs of interest. The interface circuit was designed on Eagle PCB and was fabricated using a two-layer PCB. The fabricated interface circuit was simulated with variable resistance and was verified with experiments. The system is also tested at different power source voltages and it was found that the system performance is optimum at more than 5 volts. The sensor fabrication, testing methods, and results are presented and discussed along with interface circuit design, fabrication, and characterization.</div>