Le but de cette thèse est l’obtention de matériaux multiferroïques par l’insertion de molécules organiques dans une matrice magnétique d’hydroxide simple lamellaire. Durant cette thèse a été démontré la faisabilité de la fonctionnalisation d’hydroxides simples lamellaires de cuivre et de cobalt par des molécules possédant des fonctions d’accroche acide phosphonique. Le développement des techniques de pré-fonctionnalisation a permis de fonctionnaliser ces hydroxides simple lamellaire par une variété importantes de molécules (fluorènes, benzènes, thiophènes et complexes de métaux de transition) afin d’apporter une propriété additionnelle au magnétisme de l’hydroxyde. Les premières mesures ont permis de mettre en évidence un couplage entre temperature d’ordre magnétique et anomalie diélectrique. La complexité de la mesure des propriétés diélectriques avec ces échantillons (sur poudre pastillées à froid) ont mis en lumière la nécessité d’obtenir des tailles de cristallites plus importantes. Des efforts sur la taille des cristallites ont donc été effectués et ont permis d’obtenir des monocristaux d’hydroxy- dodecylsulfate de cuivre. / The main goal of this thesis is to obtain multiferroic materials via the intercalation of organic molecules in a magnetic inorganic matrix made of layered simple hydroxide. The possibility to use phosphonic acid as grafting moiety for the functionalization of layered simple hydroxides has been demonstrated during this thesis. Pre-functionalization techniques has allowed the functionalization of layered simple hydroxides of copper and cobalt with a wide variety of molecules (fluorenes, benzenes, thiophenes or transition- metal complexes) to bring an additional property to the magnetic properties of the layered hydroxide. The first measurements revealed a coupling between magnetic ordering temperature and dielectric anomaly. The dielectric properties measurements proved to be difficult with the samples (on cold-pressed pellets) and shown the usefulness of developing new methods to improve the cristallite size. To that end, new syntheses procedures led to the obtention of mono crystals of copper-hydroxidodecylsulfonate allowing to get additional structural informations.

<p>Extrusion Deposition Additive Manufacturing (EDAM) is a process in which fiber-filled thermoplastic polymers are mixed and melted in an extruder and deposited onto a build plate in a layer-by-layer basis. Anisotropy caused by flow-induced orientation of discontinuous fibers along with the non-isothermal cooling process gives rise to internal stresses in printed parts which results in part deformation. The deformation and residual stresses can be abated by modifying the fiber orientation in the extrudate to best suit the print geometry. To that end, the focus of this research is on understanding the effect of fiber orientation state and fiber properties on effective properties of the printed bead and the final deformation of a part. The properties of three different orientation tensors of glass fiber-filled polyamide and carbon fiber-filled polyamide were experimentally and virtually characterized via micromechanics. A thermo-mechanical simulation framework developed in ABAQUS© was used to understand the effects of the varying fiber orientation tensor and fiber properties on the final deformation of printed parts. In particular, a medium-size geometry that is prone to high deformation was simulated and compared among the three orientation tensors and two material systems. This serves to be a good preliminary study to understand microscopic properties induced deformations in EDAM.</p>

Cette thèse visait à concevoir et à synthétiser des matériaux hybrides organiques-inorganiques à luminescence contrôlée et à les étudier en tant que luminophores pour l'éclairage à LED. L'objectif final était d'obtenir une source de lumière blanche. En effet, les LED blanches commerciales sont constituées d'un dispositif émetteur bleu recouvert d'un luminophore jaune. La combinaison de ces deux couleurs produit une lumière blanche. Cependant, cette lumière n'est pas de bonne qualité car il lui manque une composante rouge. Cela entraîne un mauvais rendu des couleurs des objets éclairés par ces sources de lumière. Dans notre travail, des polymères conjugués de différentes couleurs d'émission ont été obtenus avec succès. En particulier, plusieurs émetteurs de blanc ont pu être isolés.Dans cette thèse, non seulement les procédures de synthèse et les caractérisations chimiques sont présentées en détail, mais également les études des propriétés photophysiques des polymères, en solution et à l'état solide. Des études à l'état solide ont été effectuées sur les polymères et sur les polymères dispersés dans une matrice polymère. Ces études ont permis d'identifier les facteurs limitants quant aux utilisations pratiques de ces matériaux. Des solutions ont été proposées pour améliorer les performances d’émission et de stabilité des matériaux. De plus, ces travaux ont permis d'introduire la 2,2’-bipyrimidine comme nouvelle unité constitutrice pour le développement de polymères conjugués. / This thesis aimed at designing and synthesizing organic-inorganic hybrid materials with controlled luminescence and at investigating them as phosphors for LED lighting. The final goal was to obtain a white source of light. Indeed, commercial white LEDs are made up of a blue emitting device covered with a yellow phosphor. Combining these two colors yields white light. However, this light is not of good quality as it lacks some red component. This results in a bad rendering of the colors of objects illuminated by these sources of light. In our work, conjugated polymers with different emission colors have successfully been obtained. In particular, several single white emitters have been isolated.In this PhD thesis, not only the synthetic procedures and chemical characterizations are presented in detail, but also the studies of the photophysical properties of the polymers, either in solution or in the solid state. Solid state studies were performed on the bulk polymers and on the polymers dispersed into a polymeric matrix. These studies have lead to identify the limiting factors that could hamper the use of the materials. Solutions have been proposed to improve the materials performance and stability. Furthermore, 2,2’-bipyrimidine has been introduced as a new synthon for designing and developing conjugated polymers.

<p>  </p> <p>In this thesis, cellulose nanofiber (CNF) reinforced polylactic acid (PLA) filaments were produced for 3D printing applications using melt extrusion. The use of CNF reinforcement has the potential to improve the mechanical properties of PLA, making it a more suitable material for various 3D printing applications. To produce the nanocomposites, a master batch with a high concentration of CNFs was premixed with PLA, and then diluted to final concentrations of 1, 3, and 5 wt% during the extrusion process. The dilution was carried out to assess the effects of varying CNF concentrations on the morphology and mechanical properties of the composites. The results showed that the addition of 3 wt.% CNF significantly enhanced the mechanical properties of the PLA composites. Specifically, the tensile strength increased by 77.7%, the compressive strength increased by 62.7%, and the flexural strength increased by 60.2%. These findings demonstrate that the melt extrusion of CNF reinforced PLA filaments is a viable approach for producing nanocomposites with improved mechanical properties for 3D printing applications. In conclusion, the study highlights the potential of CNF reinforcement in improving the mechanical properties of PLA for 3D printing applications. The results can provide valuable information for researchers and industries in the field of 3D printing and materials science, as well as support the development of more advanced and sustainable 3D printing materials.</p>

<p>  </p> <p>High-resolution enclosed channels/fibers are highly demanded by different disciplines such as microfluidic channels for chemical synthesis, bioreactors for drug metabolism, magnetic locomotor for drug delivery, and wearable devices for motion detection. However, the current fabrication techniques for enclosed channels/fibers are restricted to a few millimeters in size. Their manufacturing often involves time and energy-consuming multi-step processes with insufficient resolution. In this work, we demonstrate a novel co-flow-enabled fabrication method to resolve the technological restrictions in the fabrication of high-resolution enclosed channels/fibers with efficient production time, controllable morphologies, and high throughput manner.</p> <p>An epoxy-based enclosed microfluidic channel was first built. A non-reactive paraffin oil and a liquid resin were pumped into a 3D-printed co-flow generator and worked as core and shell fluids, respectively. The epoxy resin was cured by external heat stimulus. As a result, the reaction region was limited between the generator wall surface and the boundary of core flow, eliminating the need for precise control over the curing system. The experiment was successfully conducted to cure build resin channel inside copper and resin tubes with good shell thickness.</p> <p>Conductive hollow hydrogel microfibers were also fabricated by this method. Sodium Alginate and Calcium Chloride were chosen as the shell and core flows, respectively. The ionic crosslinking happens at the boundary of two flows and expands outwards across the radial direction. Thus, the diameter of the hollow channel can be easily adjusted by tuning the flow rate and the size of the core flow injection needle. PEDOT: PSS, a conductive polymer, was mixed with Sodium Alginate to impart fibers with excellent electrical conductivity. The synthesized hollow microfibers have shown their functionality in stretching movement detection by serving as a fundamental building element of motion sensors. </p>

No description available.

<p>Demand for lightweight, cost-effective, structural components is driving the development of continuous fiber thermoplastic tow preforms, also known as 3D-tow or tow reinforcements, to add material performance to hybrid-molded structures as an alternative to metal components. Tow reinforcements offer the performance advantages of continuous fiber composites within molded structures. The tow reinforcements also feature more tailorability of performance compared to fabric or organo-sheet reinforced hybrid-molded structures, improving their potential for design optimization. However, the added complexity of 3D-tow reinforcement structure requires the development of unique design principles and computer aided engineering (CAE) methodologies to effectively design components which meet manufacturing and performance requirements. </p> <p><br></p> <p>A systematic evaluation of design considerations was performed comparing parts manufactured with various design features, configurations, and materials. Choosing the structural profile and balance of material properties was shown to be an important component of achieving the desired performance especially where the tow reinforcement must work in conjunction with the overmolding material to provide structural performance. </p> <p><br></p> <p>By experimentally testing representative structures with features found on automobile components and molded sports equipment, performance was evaluated for a range of material combinations and reinforcement content. Tow reinforcements were made from continuous glass or carbon fiber reinforced PA6 prepreg tape and injection overmolded with unfilled or glass fiber filled PA6 adding a shear web and rib structures. Tow reinforcement significantly reduced warpage, and in tensile loading, demonstrated potential for 340\% strength increase over parts without tow. However, three-point bend performance was dominated by the overmolding material. High strain to break overmolding materials are recommended to avoid premature overmolding material cracking. </p> <p><br></p> <p>Tensile performance of tow reinforced structures is not accurately captured by conventional modeling processes. When wrapped around load introduction points, the fibers of a thick tow traverse a shorter distance at the inner radius than the outer radius leading to waviness on the inner region of each wrap. The Hsaio and Daniel model was used to predict local elastic properties of the wavy fiber composite and spatially varying material properties were applied to 3D finite element models of a suspension link. Neglecting fiber waviness overpredicted experimental tensile stiffness and strength by 36\% and 33\% respectively while modeling waviness overpredicted stiffness and strength by only 9\% and 14\% respectively. Tow wrap configuration, waviness propagation, and material parameters have significant effect on tensile performance while the tow has little effect on compressive performance.</p> <p><br></p> <p>In addition to fiber waviness, tow bundles also spread to reconcile path length differences. A method for accounting for tow spread orientations was developed and combined with fiber waviness modeling techniques. The effects of simulating the resulting fiber orientations and effective elastic properties was used to model representative beams in tension and bending load cases and compared to previous experimental results. Accounting for fiber waviness in tension demonstrated greatly improved part stiffness predictions. Spread tow bundles improved predicted strength and stiffness over simulations where tow was constrained to a uniform cross section. Increased tow reinforcement increased bending stiffness, but failure behavior was significantly influenced by the overmolding material.  </p> <p><br></p> <p>The studies in this work identified key performance attributes of 3D-tow reinforced hybrid composite structures. Design principles and modeling techniques were developed in this work, providing improved performance predictions which brings the technology closer to widespread adoption. </p>

<p dir="ltr">Inkjet printing allows for rapid prototyping and design iteration that traditional printing methods do not. The use of inkjet printing for electronic devices has seen increased use in recent years owing to its high precision and ability to quickly test new devices. However, nearly all of this work has been done on smooth substrates with surface roughnesses on the nano scale. To further explore the capabilities of inkjet printing on rough surfaces, electrically conductive ink was printed onto a variety of solids-loaded polymer composite substrates using varied filler particle sizes with surface roughnesses on the micron scale. This work examines the necessary parameters required to print on these rough surfaces and characterizes the electrical properties of deposited ink. Electrical conductivity was demonstrated on surfaces across five distinct substrates using varied particle sizes. Further, two functional devices in the form of a heater and a strain gauge were printed and tested on these substrates. These devices showed comparable performance to commercially available devices. These findings offer improved ability to use inkjet technology on a variety of substrates and have implications in multiple fields. This demonstration of basic conductivity and advanced functionality shows the potential to continue development of complex devices and integrate them into new substrates. The optimization of printing algorithms on these rough surfaces also has significant potential to improve printability on rough surfaces and further expand capabilities.</p>

[EN] Abstract The present PhD thesis entitled "Supramolecular Chemistry: New chemodosimeters and hybrid materials for the chromo-fluorogenic detection of anions and neutral molecules" is based on the application of supramolecular chemistry and material science principles for the development of optical chemosensors for anions and neutral molecules detection. The second chapter of this PhD thesis is devoted to the preparation of chemodosimeters for the chromo-fluorogenic detection of fluoride, diisopropyl fluorophosphates (DFP) and hydrogen sulfide. The optical detection of fluoride anion was achieved by using a pyridine derivative containing a t-butyldimethylsilyl ether group. Aqueous solutions of the chemodosimeter were colorless but turned yellow upon addition of fluoride anion. Also a remarkable enhancement in emission was observed only upon the addition of fluoride. The optical changes were ascribed to a fluoride-induced hydrolysis of the silyl ether moiety. Also a chemodosimeter for the optical recognition of DFP, a nerve agent simulant, was prepared. In this case, the chemodosimeter was based on a stilbene pyridinium derivative functionalized with hydroxyl and silyl ether moieties. Aqueous solutions of the chemodosimeter were colorless changing to yellow upon DFP addition. The optical changes were ascribed to a hydroxyl phosphorylation followed by a fluoride-induced hydrolysis of the silyl ether group. Besides, that probe was implemented in test strips and DFP detection in gas phase was accomplished. Finally, the fluorogenic recognition of hydrogen sulfide anion was explored. For this purpose different fluorophores were selected and fucntionalized with 2,4-dinitrophenyl ether groups. The prepared probes were neraly non-emissive but remarkable emission enhancements upon addition of hydrogen sulfide were observed. The emission enhancements observed were due to a selective sulfide-induced hydrolysis of the 2,4-dinitrophenyl ether moiety that yielded the free fluorophores. Another set of chemodosimeters equipped with azide and sulfonylazide moieties were prepared. Again these probes were non-fluorescent but upon addition of hydrogen sulfide an important enhancement in emission was found. The selective response was ascribed to a reduction of the azide and sulfonylazide moieties to amine and sulfonylamide induced by hydrogen sulfide anion. Besides, the viability assays showed that these dosimeters were essentially non-toxic and real-time fluorescence imaging measurements confirmed their ability to detect intracellular hydrogen sulfide at micromolar concentrations. The third chapter of this PhD thesis was devoted to the preparation of nanoscopic gated materials and their use in sensing protocols. In a first step a gated material for the optical detection of glutathione (GSH) was prepared. For this purpose MCM-41 mesoporous silca nanoparticles were selected as inorganic scaffold. The pores were loaded with safranine O and the external surface was functionalized with disulfide-containing oligo(ethylene glycol) moieties. Dye delivery from aqueous suspensions of the sensory material was only observed in the presence of GSH. The signalling paradigm was ascribed to the selective reduction of the disulfide bond by GSH which induced pore opening and dye release. Also capped organic-inorganic hybrid materials for the selective detection of hydrogen sulfide were prepared and characterized. In this case the same MCM-41 support was used and charged with [Ru(bipy)3]2+ dye. Then, the external surface was functionalized with Cu(II)-macorcyclic complexes and finally, the pores were capped by the addition of the bulky anion hexametaphosphate. Aqueous suspensions of this material showed negligible dye release whereas in the presence of hydrogen sulfide anion a remarkable colour change was observed. This optical response was ascribed to a demetallation process of the Cu(II) complex induced by hydrogen sulfide. / [ES] Resumen La presente tesis doctoral titulada "Química supramolecular: Nuevos dosímetros químicos y materiales híbridos para la detección cromo-fluorogénica de aniones y moléculas neutras." está basada en la aplicación de principios básicos de la química supramolecular y de la ciencia de materiales en el desarrollo de sensores ópticos para aniones y moléculas neutras. El segundo capítulo de esta tesis doctoral está dedicado a la preparación de dosímetros químicos para la detección cromo-fluorogénica de fluoruro, diisopropil fluorofosfato (DFP) y sulfuro de hidrógeno. Para la detección óptica del anión fluoruro se sintetizó un derivado de piridina funcionalizado con un t-butildimetilsilil éter. En este capítulo también se describe la preparación de un dosímetro químico para la detección de DFP, que es un simulante de agentes nerviosos. Este dosímetro está basado en un estilbeno funcionalizado con una sal de piridinio que contiene grupos hidroxilo y silil éter en su estructura. Finalmente se prepararon dos familias de sensores para la detección óptica de hidrógeno sulfuro. La primera familia de sensores consiste en fluoróforos comunes funcionalizados con 2,4-dinitrofenil éteres. Los sensores preparados no presentaron una emisión de fluorescencia importante mientras que, en presencia del anión hidrógeno sulfuro, se observó un aumento significativo. La segunda familia de dosímetros también estaba compuesta por ciertos fluorofóros pero, en este caso, funcionalizados con grupos azida y sulfonilazida. Los dosimétros preparados, siguiendo esta segunda aproximación, tampoco dieron una fluorescencia significativa observándose un aumento de la misma al añadir el anión hidrógeno sulfuro. El tercer capítulo de esta tesis doctoral está dedicado a la preparación de materiales híbridos nanoscópicos funcionalizados con puertas moleculares y su aplicación en protocolos de reconocimiento. En primer lugar se preparó un material para la detección óptica de glutatión (GSH). Para ello se emplearon nanopartículas de MCM-41 mesoporosas como soporte inorgánico. Los poros del soporte fueron cargados con el colorante safranina O y la superficie externa funcionalizada con oligo(etilenglicol) conteniendo enlaces disulfuro. También se prepararon y caracterizaron varios materiales híbridos para la detección selectiva del anión hidrógeno sulfuro. En este caso también se empleó, como soporte inorgánico, sílice mesoporosa MCM-41. Los poros del soporte inorgánico fueron cargados con [Ru(bipy)3]2+ y la superficie externa funcionalizada con varios complejos macrocíclicos de Cu(II). El material sensor final fue obtenido al añadir el anion hexametafosfato, que compleja con los complejos de Cu(II), produciendo un bloqueo de los poros. / [CAT] Resum La present tesi doctoral titulada "Química supramolecular: Nous dosímetres químics i materials híbrids per a la detecció cromo-fluorogènica d'anions i molècules neutres." està basada en l'aplicació dels principis bàsics de la química supramolecular i de la ciència dels materials en el desenvolupament de sensors òptics per a anions i molècules neutres. El segon capítol d'aquesta tesi doctoral està dedicat a la preparació de dosímetres químics per a la detecció cromo-fluorogènica de fluorur, diisopropil fluorofosfat (DFP) i sulfur d'hidrogen. Per a la detecció òptica de l'anió fluorur es va sintetitzar un derivat de piridina funcionalitzat amb un t-dibutildimetilsilil èter. En aquest capítol també es descriu la preparació d'un dosímetre químic per a la detecció de DFP, que és un simulant d'agents nerviosos. Aquest dosímetre està basat en un estilbè funcionalitzat amb una sal de piridina que conté grups hidroxil i silis èter en la seua estructura. Finalment varen ser preparades dues famílies de sensors per a la detecció òptica de sulfur d'hidrogen. La primera família consisteix en fluoròfors comuns funcionalitzats amb 2,4-dinitrofenil èters. Els sensors preparats no presentaren una emissió de fluorescència significativa mentre que, en presencia de l'anió hidrogen sulfur, es va observar un augment significatiu. La segona família de dosímetres també estava composada per certs fluròfors però, en aquest cas, funcionalitzats amb grups azida i sulfonilazida. Els dosímetres preparats, seguint aquesta segona aproximació, tampoc donaren una fluorescència significativa observant-se un augment de la mateixa al afegir l'anió hidrogen sulfur. El tercer capítol d'aquesta tesi doctoral està dedicat a la preparació de materials híbrids nanoscòpics funcionalitzats amb portes moleculars i la seua aplicació en protocols de reconeixement. En primer lloc es va preparar un material per a la detecció òptica de glutatió (GSH). Per a aquest propòsit es varen emprar nanopartícules MCM-41 mesoporoses com a suport inorgànic. Els porus del suport varen ser carregats amb el colorant safranina O i la superfície externa funcionalitzada amb oligo(etilenglicol) que contenia enllaços disulfurs. També varen ser preparats i caracteritzats diversos materials híbrids per a la detecció selectiva de l'anió hidrogen sulfur. En aquest cas també es va emprar, com a suport inorgànic, sílice mesoporosa MCM-41. Els porus del suport inorgànic varen ser carregats amb [Ru(bipy)3]2+ i la superfície externa funcionalitzada amb diversos complexos macrocíclics de Cu(II). El material sensor final es va obtindre al afegir l'anió hexametafosfat, que es complexa amb macrocicles de Cu(II), produint un bloqueig dels porus. / El Sayed Shehata Nasr, S. (2015). Supramolecular Chemistry: New chemodosimeters and hybrid materials for the chromo-fluorogenic detection of anions and neutral molecules [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52598 / TESIS

Cette thèse s'inscrit dans le projet optique digital porté par la société Essilor, leader mondial dans le domaine de l'optique ophtalmique. La collaboration entre le laboratoire Charles Coulomb et Essilor a donné naissance à une nouvelle génération de systèmes optiques apposés directement sur le verre ophtalmique. Ce système est constitué de microcuves remplies d'un autre matériau pouvant être différent d'une cuve à l'autre. Il en résulte une pixellisation de la surface permettant des phénomènes optiques innovants. La première partie de ce travail est consacrée à la synthèse et à la caractérisation de résines hybrides organiques-inorganiques photosensibles fonctionnant à différentes longueurs d'ondes. Le but est de créer les microcuves par un procédé de photolithographie dont la rigidité est telle que les murs puissent résister au remplissage par un liquide. Les polymérisations minérales et organiques de ces résines ont été étudiées d'un point de vue structural (spectroscopie infrarouge et RMN), mécanique (technique de nanoindentation) et texturale (absorption - désorption de gaz). La deuxième partie porte sur l'incorporation d'une couche ultraporeuse à l'intérieur des microcuves. Le choix final s'est porté sur un aérogel de silice mélangé à un polymère et réalisé par séchage en condition supercritique du CO2. Ses propriétés sont caractérisées par diverses techniques comme le MEB, les spectroscopies infrarouge et UV-Visible, la microscopie AFM et la nanoindentation. Ce système constitué de microcuves remplies d'un matériau ultraporeux peut alors être imprégné localement par différents liquides d'indice de réfraction variés afin d'obtenir les effets optiques désirés. / This thesis is feeling part of the optical digital project carried out by Essilor, the world leader in the ophthalmic optics field. The collaboration between the Charles Coulomb Laboratory (LCC) and Essilor has spawned a new generation of optical systems affixed directly on the ophthalmic glass. This system consists of microtanks filled with material that may be different from one tank to the other. The result is a pixelated surface which can be lead to innovative optical phenomena. The first part of this work is devoted to the synthesis and characterization of photosensitive organic-inorganic hybrid resins operating at different wavelengths. The goal is to create by a photolithography process microtanks whose rigidity is such that the walls can resist with a liquid filling. Polymerizations of hybrid photosensitive resins have been studied in a structural (infrared and NMR spectroscopy), mechanical (nanoindentation technique) and textural (absorption - desorption of gas) way. The second part focuses on the ultraporous layer incorporation inside microtanks. The final choice fell on silica aerogel containing polymer and obtained under CO2 supercritical drying conditions. Its properties are characterized by various techniques such as SEM, infrared and UV-Visible spectroscopy, AFM microscopy and nanoindentation technique. The all system consists of microtanks filled with an ultraporous material which can be locally impregnated by different liquids with a varied refractive index to obtain the desired optical effects.