Polymerní nanokompozity na bázi polyhedrálních oligomerních silsesquioxanů (POSS) představují slibnou oblast výzkumu, která potenciálně může využít samouspořádávní při navrhování nových materiálů. Tato diplomová práce popisuje postup přípravy oktafenyl-POSS/PS, oktafenyl-POSS/PMMA a oktamethyl-POSS/PS systémů a charakterizaci jejich termomechanických vlastností v pevné fázi a reologických vlastností v roztoku. Získané výsledky jsou diskutovány s přihlédnutím k teoriím zabývajících se stavem disperze nanočástic.

Heterogeneous line broadening and spectral diffusion of the fluorescence emission spectra of perylene diimide molecules have been investigated by means of time dependent single molecule spectroscopy. The influence of temperature and environment has been studied and reveals strong correlation to spectral diffusion processes. We followed the freezing of the molecular mobility of quasi free molecules on the surface upon temperature lowering and by embedding into a poly(methyl methacrylate) (PMMA) polymer. Thereby changes of optical transition energies as a result of both intramolecular changes of conformation and external induced dynamics by the surrounding polymer matrix could be observed. Simulations of spectral fluctuations within a two-level system (TLS) model showed good agreement with the experimental findings.

[pt] Este trabalho teve como objetivo comparar as diferentes influências que aditivos e tratamentos térmicos têm sobre as propriedades ópticas e elétricas de filmes finos semicondutores formados por polímeros contendo principalmente bitiofenos e fluorenos. Os polímeros contendo tiofenos em sequência, como o poli[(9,9-dioctilfluorenil-2,7-diil)co-bitiofeno] (F8T2), apresentam conformações cis e trans dependente da posição relativa dos átomos de enxofre, tendo suas propriedades alteradas de acordo com a proporção entre os domínios de ambas as conformações em um mesmo filme. Os átomos de iodo presentes no aditivo 1,8- diiodooctano são tidos como uma possível forma de alterar os agregados nesse polímero e, consequentemente, alterar as propriedades físicas do filme formado. Para aumentar o entendimento sobre os átomos diferentes de carbono e hidrogênio nos aditivos foram estudados os efeitos dos aditivos 1,8-diiodooctano, 1,8- octanoditiol e octano, que contém dois iodos, dois enxofres e não contém heteroátomos, respectivamente, em sua composição. Além disso, foi estudada a introdução do polímero PMMA (polimetilmetacrilato) de forma que alterasse a estrutura interna do filme fino e também foram estudados tratamentos térmicos em diferentes temperaturas, uma vez que parâmetros como tempo de evaporação do solvente também influenciam a formação e as propriedades do filme após seu crescimento. Outro ponto de interesse foi justamente a composição dos polímeros, para tal, foram estudados, além do F8T2, os polímeros poli(9,9-dioctilfloureno) (PFO), poli(9,9-dioctilfluoreno-cobenzotiadiazol) (F8BT) e poli(3-hexiltiofeno-2,5-diil) regiorregular (rrP3HT). Eles são formados, respectivamente, por bitiofenos e fluorenos, apenas fluorenos, fluorenos e benzotiadiazol e apenas politiofenos. Dessa forma, seria possível isolar as contribuições de cada grupo isolado e combinados com grupos que permitem ou não a mudança entre conformações. Os filmes foram depositados em substratos de vidro pela técnica de spin-coating e a caracterização foi feita com medidas de absorção, fotoluminescência e FTIR. Quando possível, foram realizadas medidas CELIV e corrente-tensão de dispositivos fotovoltaicos usando os polímeros como camada doadora de elétrons. Com este trabalho foi possível variar as intensidades dos picos de absorção e alterar o gap de energia dos polímeros. Destacando a ação do DIO, observou-se que a conformação cis do F8T2 é maximizada quando se utiliza 1 por cento do aditivo. Além disso, o DIO também aumenta a porcentagem de fase beta do PFO. Já para o P3HT, foi constatado um aumento no ordenamento do filme. / [en] This work aimed to compare the different influences that additives and heat treatments have on the properties of semiconductor thin films formed by polymers containing mainly bitiophenes and fluorenes. Polymers containing thiophenes in sequence, such as poly[(9,9-dioctylfluorene-2,7-diyl)co-bithiophene] (F8T2), have cis and trans conformations depending on the relative position of the sulfur atoms, having their optical and electrical properties altered according to the proportion between the domains of both conformations in the same film. The iodine atoms present in the additive 1,8-diiodooctane are considered as a possible way to change the aggregates in this polymer and, consequently, change the physical properties of the formed film. To increase the understanding of the atoms other than carbon and hydrogen in the additives, the effects of the additives 1,8-diiodooctane, 1,8- octanodithiol and octane, which contain two iodines, two sulfur and do not contain heteroatoms, respectively, were studied. In addition, the introduction of the PMMA (polymethylmethacrylate) polymer was studied in order to alter the internal structure of the thin film and, also, heat treatments at different temperatures were studied, since parameters such as solvent evaporation time and the available thermal energy also influence the formation and properties of the film after its growth. Another point of interest was precisely the composition of the polymers. For this purpose, in addition to F8T2, the polymers poly(9,9-dioctylflourene) (PFO), poly(9,9-dioctylfluorene-cobenzothiadiazole) (F8BT) and regioregular poly(3- hexylthiophene-2,5-diyl) (rrP3HT) were studied. They are formed, respectively, by bitiophenes and fluorenes, only fluorenes, fluorenes and benzothiadiazole and only polythiophenes. In this way, it would be possible to isolate the contributions of each isolated and combined groups that allow or not to change between conformations. The films were deposited on glass substrates using the spin-coating technique and the characterization was done via absorption, photoluminescence and FTIR measurements. When possible, CELIV and current-voltage measurements of photovoltaic devices were performed using the polymers as an electron donor layer. With this work it was possible to vary the intensities of the absorption peaks and to change the energy gap of the polymers. Highlighting the action of DIO, it was observed that the cis conformation of F8T2 is maximized when 1 percent of the additive is used. In addition, DIO also increases the percentage of beta phase of PFO. For P3HT, on the other hand, there was an increase in the ordering of the film.

Les risques liés à la propagation de fissures sous impact sont encore très difficiles à estimer. La détermination de critères de rupture dynamique uniquement à partir de résultats expérimentaux reste délicate. Ainsi la première étape pour valider des lois de propagation de fissures sous impact passe par le développement d'outils de simulation numérique. Depuis les années 1970, de nombreux codes de calcul mécanique ont été dédiés à l'étude de la propagation de fissures, notamment dans le cas du phénomène de fatigue. La principale difficulté consiste dans la nécessité de suivre la géométrie de la fissure au cours du temps. Ces dernières années, des méthodes alternatives basées sur la partition de l'unité ont permis une description implicite des discontinuités mobiles. C'est le cas de la méthode des éléments finis étendue (X-FEM) qui paraît particulièrement adaptée à la simulation de la propagation dynamique de fissures sous chargement mixte où les trajets de fissures ne sont pas connus a priori. Si ces outils numériques permettent maintenant de représenter l'avancée dynamique d'une fissure, les résultats numériques doivent être comparés à des résultats expérimentaux pour s'assurer que les lois introduites sont physiquement fondées. Notre objectif est donc de développer conjointement des techniques expérimentales fiables et un outil de simulation numérique robuste pour l'étude des phénomènes hautement transitoires que sont l'initiation, la propagation, l'arrêt et le redémarrage de fissures sous impact.<br />Des expériences de rupture dynamique ont donc été réalisées sur du Polyméthacrylate de méthyle (PMMA) durant lesquelles la mixité du chargement varie et des arrêts et redémarrages de fissures se produisent. Deux bancs d'essais différents ont été utilisé, le premier basé sur la technique des barres de Hopkinson (ou barres de Kolsky), le second mettant en jeu un vérin rapide. Le PMMA étant transparent, la position de la fissure au cours de l'essai a été acquise grâce à des caméras rapides mais aussi en utilisant un extensomètre optique (Zimmer), habituellement dédié à la mesure de déplacements macroscopiques d'un contraste noir/blanc. L'utilisation de cet extensomètre pour suivre la fissure au cours de l'essai a permis d'obtenir une localisation très précise de la pointe de la fissure en continu, permettant ainsi l'étude des phases transitoires de propagation. Afin d'étudier le même phénomène dans des matériaux opaques comme les aluminiums aéronautiques (Al 7075), des techniques de corrélation d'images numériques ont été employées en mouchetant les éprouvettes impactées. De nouveaux algorithmes ont été développés afin de traiter les images issues d'une caméra ultra-rapide (jusqu'à 400 000 images par seconde).<br />Plusieurs géométries ont été envisagées afin d'étudier différents cas de propagation dynamique : initiation en mode I pur, initiation en mode mixte, propagation, arrêt, redémarrage, interaction entre deux fissures, influence d'un trou sur le trajet d'une fissure, branchement dynamique de fissures. Ces expériences ont ensuite été reproduites numériquement afin de valider les algorithmes et les critères de rupture choisis.

<div> <div> <div> <p>Organic-inorganic halide perovskite solar cells have increased efficiencies substantially (from 3% to > 22%), within a few years. However, these solar cells degrade very rapidly due to humidity and no longer are capable of converting photons into electrons. Methylammonium Lead Triiodide (CH3NH3PbI3 or MAPbI3) is the most common type of halide perovskite solar cell and is the crystal studied in this thesis. Graphene is an effective encapsulation method of MAPbI3 perovskite to reduce degradation, while also being advantageous because of its excellent optical and conductive properties. Using a PMMA transfer method graphene was chemical vapor depostion (CVD) grown graphene was transferred onto MAPbI3 and reduced the MAPbI3 degradation rate by over 400%. The PMMA transfer method in this study is scalable for roll-to- roll manufacturing with fewer cracks, impurites, and folds improving upon dry transfer methods. To characterize degradation a fluorescent microscope was used to capture photoluminescence data at initial creation of the samples up to 528 hours of 80% humidity exposure. Atomic force microscopy was used to characterize topographical changes during degradation. The study proves that CVD graphene is an effective encapsulation method for reducing degradation of MAPbI3 due to humidity and retained 95.3% of its initial PL intensity after 384 hours of 80% humidity exposure. Furthermore, after 216 hours of 80% humidity exposure CVD graphene encapsulated MAPbI3 retained 80.2% of its initial number of peaks, and only saw a 35.1% increase in surface height. Comparatively, pristine MAPbI3 only retained 16% of its initial number of peaks and saw a 159% increase in surface height. </p> </div> </div> </div>

Une étude expérimentale du vieillissement des matériaux vitreux,<br />basée sur l'analogie entre verres de spin et verres structuraux, a<br />été réalisée en introduisant une température effective Teff<br />pour ces systèmes faiblement hors équilibre. Cette nouvelle<br />observable se mesure via le rapport fluctuation dissipation.<br /><br />La mesure de Teff sur les propriétés diélectriques d'un verre<br />polymérique (polycarbonate) après une trempe sous la température<br />de transition vitreuse montre que le théorème fluctuation<br />dissipation est fortement violé. L'amplitude et la persistance<br />dans le temps de cette violation sont des fonctions décroissantes<br />de la fréquence. Autour de 1 Hz, elle persiste plusieurs heures.<br />L'origine de la violation semble être due à une dynamique<br />fortement intermittente caractérisée par de grandes fluctuations.<br />Cette intermittence semble dépendre de la vitesse de trempe et de<br />la température d'arrêt. Une interprétation théorique basée sur le<br />modèle en piège permet de rendre compte de cette dynamique.<br /><br />Un comportement intermittent très similaire a été observé pour un<br />verre colloïdal (Laponite) pendant la transition de l'état liquide<br />à l'état solide alors qu'aucune violation ou intermittence n'ont<br />été observées après une trempe lente réalisée sur un autre verre<br />polymérique, le poly(méthyl méthacrylate) (PMMA).<br /><br />Nous présentons également une mesure mécanique préliminaire de la<br />relation fluctuation dissipation sur une tige de polycarbonate à<br />l'aide d'un interféromètre de Nomarski à deux bras.

PMMA is a widely used biomaterial especially in the fields of orthopedia, orthodontia and ophthalmology. When biocompatibility is considered, modification of the biomaterials&amp / #8217 / surface may be needed to optimize interactions of the biomaterial with the biological environment. After the surface modifications one of the most important changes that occur is the change in the surface free energy (SFE). SFE is an important but an obscure property of the material and evaluation methods with different assumptions exist in the literature. In this study, SFE of pristine and oxygen plasma modified PMMA films were calculated by means of numerous theoretical approaches (Zisman, Saito, Fowkes, Berthelot, Geometric and Harmonic Mean and Acid-Base) using numerous liquids and the results were compared to each other to elucidate the differences of methods. Dispersive, polar, acidic and basic components of the SFE were calculated by the use of different liquid couples and triplets with the application of Geometric and Harmonic mean methods and Acid-Base approach. The effect of SFE and the components of SFE on the cell attachment efficiencies were examined by using fibroblast cells. It was observed that with the treatment of oxygen plasma, cell attachment capability and hydrophilicity of PMMA surfaces were altered depending on the applied power and duration of the plasma.

<p>This thesis deals with the engineering of novel nanomaterials, particularly nanocomposites and nanostructured surfaces with enhanced functionalities. The study includes two parts; in the first part, an in situ sol-gel polymerization approach is used for the synthesis of polymer-inorganic hybrid material and its exceptional transparent UV-shielding effect has been investigated. In the second part, electrodeposition process has been adapted to engineer surfaces and the boiling performance of the fabricated nanostructured surfaces is evaluated.</p><p>In the first part of the work, polymer-inorganic hybrid materials composed of poly(methylmethacrylate) (PMMA) and zinc compounds were prepared by in situ sol-gel transition polymerization of zinc complex in PMMA matrix. The immiscibility of heterophase of solid organic and inorganic constituents was significantly resolved by an in situ sol-gel transition polymerization of ZnO nanofillers within PMMA in the presence of dual functional agent, monoethanolamine, which provided strong secondary interfacial interactions for both complexing and crosslinking of constituents.</p><p>In the second part of the work, nanoengineering on the surface of copper plates has been performed in order to enhance the boiling heat transfer coefficient. Micro-porous surfaces with dendritic network of copper nanoparticles have been obtained by electrodeposition with dynamic templates. To further alter the grain size of the dendritic branches, the nanostructured surfaces underwent a high temperature annealing treatment.</p><p>Comprehensive characterization methods of the polymer-inorganic hybrid materials and nanoengineered surfaces have been undertaken. XRD, 1H NMR, FT-IR, TGA, DSC, UV-Vis, ED, SEM, TEM and HRTEM have been used for basic physical properties. Pool boiling tests were performed to evaluate the boiling performance of the electrodeposited nanostructured micro-porous structures.</p><p>The homogeneous PZHM exhibited enhanced UV-shielding effects in the entire UV range even at very low ZnO content of 0.02 wt%. Moreover, the relationship between band gap and particle size of incorporated ZnO by sol-gel process was in good agreement with the results calculated from the effective mass model between bandgap and particle size. The fabricated enhanced surface has shown an excellent performance in nucleate boiling. At heat flux of 1 W/cm2, the heat transfer coefficient is enhanced over 15 times compared to a plain reference surface. A model has been presented to explain the enhancement based on the structure characteristics.</p>

Le traitement d'une infection ostéo-articulaire nécessite une prise en charge longue, obligeant à des chirurgies itératives et à un traitement antibiotique systémique prolongé. À ce jour, le polyméthacrylate de méthyle est le vecteur d’antibiotique local le plus fréquemment utilisé chez l’homme pour traiter une infection ostéo-articulaire. Cependant les PMMA sont non résorbables et obligent à multiplier les interventions chirurgicales afin d’aboutir au traitement définitif de l’infection ostéo-articulaire. Le PMMA ne permet pas une libération complète de l’antibiotique avec de surcroît des doses inférieures à la CMI du germe en cause, pouvant faciliter l’émergence de bactéries résistantes. L'objectif de notre travail était d’obtenir une libération locale efficace et prolongée d’antibiotique grâce à un polymère entièrement résorbable. Le cahier des charges établi pour l’élaboration de ce polymère était le suivant : système matriciel offrant une libération de gentamicine à une dose de 1 à 2 mg/jour/g de mélange sur une période de plus de 10 jours. De plus, le polymère devait être bio-résorbable, c’est-à-dire qu’il devait pouvoir être dégradé jusqu'à obtenir des fragments pouvant être éliminés naturellement par l'organisme. Afin de répondre à ces exigences, il a été créé le PLA50P, Poly(D,L-acide lactique) de haut poids moléculaire. Afin d’obtenir le mélange gentamycine-PLA, une technique de compression des poudres des deux composants a été mise en œuvre. Ce polymère pouvait être stérilisé par -irradiation, sans influence sur les caractéristiques de relargage du polymère.La cinétique in vitro de la gentamicine relarguée par le PLA50GS montrait un pic maximum de gentamicine libérée obtenu à 12 jours et une stabilisation ensuite jusqu’à 63 jours de la quantité relarguée. La quantité cumulée de gentamicine relarguée à 3 semaines in vitro est de 54 % de la quantité contenue initialement dans PLA50GS. In vivo, nous observions une libération in situ de 5,1 µg/mL de gentamicine à J3, de 1,9 µg/mL de gentamicine à J7 et de 0 µg/mL à 5 semaines avec disparition de PLA50GS à l’examen macroscopique. Nous avons ainsi pu mettre en évidence, in vitro et in vivo, un relargage de la gentamicine à des doses supérieures à la CMI du germe et ce pendant plus de trois semaines.Afin de confirmer ces observations, nous avons ensuite mis au point un modèle d’infection périostée chez le rat. Pour ce faire nous avons utilisé des rats âgés de 10 à 12 semaines avec une injection au contact de l’os et au 1/3 moyen de la patte arrière de deux fois 100 ml de SAMS d’origine animale. L’utilisation du PLA50GS a montré sa supériorité par rapport à une administration parentérale d’une dose équivalente de Gentamicine avec une négativation du contage bactériologique chez tous les rats traités par le polymère chargé à la Gentamicine. Nous avons ensuite voulu traiter une infection articulaire grâce à notre polymère. Nous avons donc créé un modèle animal utilisant un lapin femelle de 4 kg avec une injection de 1 ml d’une solution à 103 CFU/ml de staphylococcus méthi-sensible d’origine léporidée. Le PLA50GS nous a permis de réduire très significativement la charge bactérienne intra-articulaire (baisse de 3 à 4 log10 soit 1000 à 10000 fois moins de bactéries) alors que le traitement antibiotique par voie générale dit de référence ne nous a pas permis de réduire l’infection intra-articulaire de façon significative par rapport au groupe non traité. Le PLA50GS nous a ainsi permis de réduire l’infection de 3 log10 par rapport aux autres groupes avec 2 lapins sur 6 guéris de leur infection.Le PLA50GS présente, ainsi, les caractéristiques suivantes : (i) stabilité de la Gentamicine au sein du polymère, (ii) polymère sous forme de poudre stable, (iii) relargage prolongé de la Gentamicine pendant plusieurs semaines, (iv) effet « burst » présent mais limité, (v) très bonne biotolérance, et (vi) efficacité supérieure aux traitements antimicrobiens classiques. / The treatment of soft-tissue infections, osteomyelitis, and acute or chronic septic arthritis is a lengthy process that involves repeated surgical procedures and the systemic administration of antibiotics for at least 6 weeks to 3 months. Poor diffusion of antibiotics into bones and joints requires high doses given parenterally for long periods. At present, the antibiotic vector most widely used in humans with bone or joint infections is polymethylmethacrylate. Because PMMA is not bioabsorbable, multiple surgical procedures are required to eradicate infection. Furthermore, PMMA does not release its full antibiotic load over time and may yield local antibiotic concentrations lower than the minimal inhibitory concentration of the causative organism, thereby promoting the emergence of resistant strains. The objective of our work was to develop a fully bioabsorbable polymer capable of ensuring the prolonged and efficient release of its antibiotic load, thus improving the management of bone and joint infections. The specifications for the polymer included the release by the matrix system of 1-2 mg of gentamicin per day and per gram of mixture over more than 10 days. Other specifications were appropriate physical characteristics, a drug release rate sufficient to ensure optimal treatment safety, and ease of implantation. The polymer was also to be bioabsorbable, i.e., subject to degradation into fragments capable of being eliminated naturally by the body. High-molecular weight PLA50P, Poly(D,L-lactic acid) was created and found to meet these specifications. Use of this polymer as large particles (0.5 to 1 mm) limited the initial burst phenomenon. A gentamicin-PLA50P mixture was obtained by compression of the two components prepared in powder form. The antibiotic load was set at 20% to limit the initial burst. The polymer can be sterilized by gamma irradiation, which has no effect on drug release characteristics.In vitro kinetic studies of gentamicin release by the polymer showed a peak on day 12 followed by a plateau that lasted until day 63. After 3 weeks, the cumulative amount of gentamicin released in vitro was 54% of the total amount loaded onto the polymer. In vivo gentamicin concentrations measured in situ were 5.1 µg/mL on day 3, 1.9 µg/mL on day 7, and 0 µg/mL on day 35, when the polymer was no longer visible to the naked eye. Thus, both in vivo and in vitro, gentamicin was released in concentrations greater than the MIC of the microorganism, for longer than 3 weeks.To test the gentamicin-loaded polymer, we created a rat model of periosteal infection. Rats aged 10-12 weeks received two 100 mL injections of methicillin-susceptible Staphylococcus aureus collected from animals, into the middle third of the hind leg, in contact with the bone. Treatment with gentamicin-loaded PLA50P proved superior over parenteral administration of an equivalent gentamicin dose, consistently reverting the bacteriological cultures to negative. We then created a rabbit model of septic arthritis. A doe weighing 4 kg received an add intraarticular injection of 1 mL of a solution containing 103 cfu/mL of a methicillin-sensitive S. aureus strain collected from another rabbit. Gentamicin-loaded PLA50P treatment induced a highly significant drop in the intraarticular bacterial load (by 3-4 log10), whereas standard systemic gentamicin therapy failed to significantly diminish bacterial counts comparatively to the untreated controls. Thus, gentamicin-loaded PLA50P diminished the bacterial load by 3 log10 comparatively to the other groups and allowed eradication of the infection in 2 of the 6 rabbits.In sum, gentamicin-loaded PLA50P (i) ensures the stability of the antibiotic; (ii) is available as a stable powder; (iii) ensures the prolonged release of gentamicin over several weeks; (iv) produces a limited burst effect; (v) exhibits very good biotolerance; (vi) and is more effective than standard antimicrobial therapy.

This thesis deals with grayscale e-beam lithography and diffractive optical elements fabrication. Three topics are addressed. The first topic is combined grayscale e-beam lithography. The goal of this task is combining exposures performed by two systems with various beam energies. This combined technique leads to a better usage of both systems because various structures can be more easily prepared by one electron beam energy than by the other. The next topic is the optimization of shape borders of exposing structures that are defined by image input. The influence of such optimization on exposure data preparation is evaluated, as well as the exposure time and the change of optical properties of testing structures. The possibility of deep multilevel diffractive optical element fabrication in plexiglass blocks is researched as the third topic. Plexiglass can replace the system of a resist and a substrate. A new approach to writing down the structures by electron beam is presented, minimizing thermal stress on the plexiglass block during the exposure. The writing method also improves the homogeneity of exposed motifs. A method for computing the exposure dose for specific multilevel structures was designed. This method is based on the existing model of proximity effect computation and it minimizes the computing time necessary to obtain the exposure doses.