A subluxação atlantoaxial em cães miniatura culmina em compressão da medula espinhal e mielopatia cervical de graus variáveis. Frequentemente o tratamento cirúrgico se faz necessário, sendo os implantes transarticulares uma das opções terapêuticas. Convencionalmente a passagem desses implantes baseia-se em pontos anatômicos de referência e ângulos genéricos preestabelecidos, todavia, devido ao estreito corredor ósseo o posicionamento ideal é desafiador. O desenvolvimento de métodos de planejamento cirúrgico individualizados poderia aumentar a acurácia na aplicação de implantes atlantoaxiais. O presente estudo teve como objetivo desenvolver um guia cirúrgico paciente-específico (GCPE) para colocação de pinos atlantoaxiais em cães miniaturas e comparar a eficácia desses dispositivos em relação a técnica cirúrgica convencional. Para tanto, dezesseis cadáveres de cães de até seis quilogramas foram dispostos aleatoriamente em dois grupos de oito cães, para serem submetidos a cirurgia de estabilização transarticular atlantoaxial com pinos lisos de 1,6 mm. Nos cães do Grupo A (GrA) a aplicação dos pinos foi guiada por um GCPE, desenvolvido com base em imagens de tomografia computadorizada (TC), a partir de técnicas de prototipagem rápida e impressão 3D por modelagem por fusão e deposição. Os cães do Grupo B (GrB), foram submetidos ao procedimento operatório convencional, sendo a passagem dos pinos guiada por referências anatômicas. Posteriormente ambos os grupos foram submetidos à exame de TC para avaliação da acurácia dos pinos. Para a avaliação do posicionamento dos implantes criou-se uma escala que ponderou a manutenção nos corredores seguros e os classificou de acordo com a estabilidade oferecida e a segurança da aplicação. Observou-se que não houve diferença significativa entre o método com GCPE e a cirurgia convencional, sendo que ambos grupos tiveram resultados expressivos de pinos inadequadamente aplicados, incluindo violação de corticais com obliteração do forame vertebral em 3 (37,5%) cães do GrA e 4 (50%) cães do GrB e obliteração do forame transverso em 3 (37,5%) animais do GrA e 1 (12,5%) do GrB. A aplicação de pinos em posição adequada bilateralmente foi observada em apenas 2 (25%) cães de cada grupo. Concluímos que a confecção de um GCPE para pinos transarticulares em cães miniaturas é viável, todavia, o modelo criado não foi capaz de aumentar a eficácia e segurança da cirurgia em relação à técnica convencional. / The atlantoaxial subluxation in miniature dogs leads to spinal cord compression and cervical myelopathy in several degrees. Commonly the surgical treatment is necessary, and one of therapeutic options are the transarticular fixation. Conventionally the passage of these implants is based on anatomical reference points and generics pre-established angles, however, due to the narrow bony corridor the ideal positioning is challenging. The development of individual surgical planning methods could improve the accuracy of atlantoaxial implants application. The present study aimed to develop a patient-specific surgical guide (PSSG) for placement of atlantoaxial pins in miniature dogs and to compare the efficacy of these devices related to the conventional surgical technique. Sixteen cadavers of dogs, up to six kilograms, were randomly placed in two groups of eight dogs each, to undergo atlantoaxial transarticular stabilization with Kirschner wires. On the Group A (GrA) the application of Kirschner wire were guided by a PSSG, developed based on computed tomography (CT) images, using rapid prototyping and fused deposition modeling 3D impression technique. The dogs of Group B (GrB) were submitted to conventional procedure, with the passage of the Kirschner wires guided by anatomical references. After surgeries, dogs in both groups were submitted to a CT scan to evaluate the accuracy of the implants. To evaluate the implants position a scale was created and considered the maintenance of the pins in the safe corridors and classified them according to the stability and safety of the application. It was observed that there was no significant difference between the PSSG method and the conventional surgery, and that both groups had expressive results of inappropriately applied pins, including obliteration of vertebral foramen in 3 (37.5%) dogs from GrA and 4 (50%) dogs from GrB and obliteration of the transverse foramen in 3 (37.5%) dogs from GrA and 1 (12, 5%) dog of GrB. The bilaterally application of pins in a suitable position was observed in only 2 (25%) dogs of each group. We concluded that the development of a PSSG for transarticular pins in miniature dogs is feasible, however, the model that we design was not able to increase the efficacy and safety of the surgery, compared to the conventional surgical technique.

A confecção de trabalhos protéticos em um fluxo digital é possível a partir do escaneamento intra-oral e confecção da Prótese via CAD/CAM. A tecnologia atual de impressão 3D permite a obtenção de um modelo impresso, para a realização de determinados procedimentos. Entretanto, é necessário analisar e comparar estes modelos com os modelos de gesso, uma vez que existe uma diferença significativa na forma de obtenção, assim como, nos custos de cada tipo de modelo. O presente estudo teve como objetivo realizar uma análise da acurácia entre modelos impressos, obtidos por meio de escaneamento intra-oral e impressão 3D, e modelos de gesso obtidos pelo método de moldagem convencional. Foi utilizado um manequim odontológico como modelo mestre e foram confeccionados dez modelos de gesso (n= 10), pela técnica de moldagem da dupla impressão com silicone de adição. Foram utilizados dois tipos de escâneres intra-orais e dois tipos de impressoras 3D, que formaram quatro grupos experimentais com dez modelos por grupo (n= 10). Os modelos físicos de gesso e impressos foram comparados com o modelo mestre por meio de análises de medições lineares em seis sítios de medições, com o uso de uma máquina de medição por imagem (Quick Scope, Mitutoyo®). A análise dos modelos impressos incluiu as possíveis interações entre os fatores principais tipo de impressora, tipo de escâner e sítios de medições. Os resultados mostraram que em relação ao modelo mestre, no geral, as discrepâncias dos modelos de gesso foram menores que as discrepâncias dos modelos impressos. A análise das interações dos fatores principais indicou que o tipo de impressora exerceu a maior influência na acurácia dos modelos impressos, seguido do fator sítio de medição e tipo de escâner. Pôde-se concluir que os modelos de gesso apresentaram uma acurácia superior quando comparados com os modelos impressos. O acabamento superficial dos modelos impressos exerceu influência na sua acurácia. / The preparation of prosthetic restoration in a digital flow is possible using intraoral scanning and confection of the prosthesis via CAD/CAM. The current 3D printing technology allows the making of a printed cast, for performing certain laboratory procedures. However, it is necessary to analyze and compare these casts with the gypsum casts, since there is a significant difference in the form of obtaining, as well as, in the costs of each type of cast. The objective of the present study was to perform a comparative study of the accuracy of printed casts, obtained through intraoral scanning and 3D printing, and gypsum casts, obtained through the conventional impression. A dental mannequin was used as the master model and ten gypsum casts (n=10) were obtained, using double impression technique with polyvinyl siloxane. Two types of intraoral scanners and two types of 3D printers were used, which formed four experimental groups with ten models per group (n=10). The real gypsum and printed casts were compared to the master model by linear measurements in six sites, using an image-measuring machine (Quick Scope, Mitutoyo®). The analysis of the printed models included possible interactions between the factors type of printer, type of scanner and measurement sites. The results showed that, in relation to the master model, in general, the discrepancies of the gypsum casts were smaller than the discrepancies of the printed casts. The interactions of the factors analysis indicated that the type of printer exerted the greatest influence on the accuracy of the printed casts, followed by the site measurement and type of scanner. It was conclude that the gypsum casts presented superior accuracy when compared to the printed casts. The surface finish of the printed casts exerted influence in its accuracy.

Les polymères ferroélectriques et plus récemment les matériaux électrostrictifs ont attiré l’attention de la communauté scientifique en raison de leur capacité de conversion d’une excitation électrique en une réponse mécanique et vice versa. La synergie entre les propriétés électro actives de ces polymères et leurs propriétés physico-chimiques intrinsèques (souplesse, légèreté, grande résistance mécanique, facilité de mise en œuvre etc.) en font des candidats de choix pour des applications de types capteurs et actionneurs souples. Cette thèse vise à déterminer de façon systématique le comportement électromécanique des terpolymères P (fluorure de vinylidène-trifluoréthylène-chlorotrifluoroéthylène) [P (VDF-TrFE-CTFE)] par des techniques de cristallisation et de technologies additives et entend étendre ces terpolymères à l'application des dispositifs de type capteur de force électromécanique. L'influence du traitement thermique sur la réponse électromécanique et la microstructure des terpolymères a d'abord été étudiée. Il a été mis en évidence que la déformation électrostrictive transversale S31 pour chaque terpolymère traité thermiquement suit une loi quadratique avec le champ électrique. Par ailleurs il a été démontré que la déflexion d’un actionneur unimorphe est maximisée pour une fraction de phase cristalline de 39,3%. La dynamique moléculaire des terpolymères cristallisés a également été étudiée par spectroscopie diélectrique à large bande. Une dynamique segmentaire contrainte a été observée dans le terpolymère contenant la fraction cristalline la plus élevée pour laquelle une distribution étroite du temps de relaxation a été mise en évidence. En outre, il a été démontré que l’ajout d’agent plastifiant permet d’augmenter de manière significative la réponse électromécanique des terpolymères fluorés, ouvrant la voie vers de nouveaux matériaux électrostrictifs hautes performances fonctionnant sous faible champ électrique. De plus, la réponse diélectrique et électromécanique accrue du terpolymère dopé a été étudiée par microscope à force atomique et spectroscopie diélectrique dynamique. Ces analyses ont permis de lier l’augmentation de la réponse électromécanique de ces mélanges à un effet de polarisation interfaciale intensifié lors de l’augmentation de mobilité moléculaire de la phase amorphe rigide de ces terpolymères fluorés. Enfin, des dispositifs électromécaniques basés sur le polymère ferroélectrique P (VDF-TrFE) et le terpolymère électrostrictif P (VDF-TrFE-CTFE) ont été élaborés. Un procédé de fabrication additive utilisant la technologie d'impression jet d'encre a permis de concevoir et valider la faisabilité de réalisation de capteurs de force dynamique. Il a alors été démontré que les propriétés pseudo-piézoélectriques du terpolymère électrostrictif sont équivalentes à celles du copolymère ferroélectrique pour un faible champ électrique de biais de 7,5 V /μ / Electromechanical coupling effect has been paid the increasing attention due to ability to realize conversion between electric excitation and mechanical response and vice versa. Thanks to their flexibility, light weight, relatively low mechanical strength, ease of processability into large-area films, and ability to be molded into desirable geometric dimensions, polymers materials which possess an electromechanical coupling effect have been emerging recently. This thesis aims to systematically determine the electromechanical behavior of the P(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] terpolymers via crystallization and additive technology approaches and intend to extend such terpolymers to the electromechanical force sensor devices application. The influence of the thermal processing on the electromechanical response and microstructure of the terpolymers were firstly investigated. Cantilever unimorph bending measurement found the tip displacement δ and transverse strain S_31 for each thermally treated terpolymer followed a quadratic correlation with the electric field. δ was maximized at a 39.3% crystal content, instead of S_31 peaking at lowest crystal content, showing an exponential decay against the crystal fraction increasing. The dynamics of crystallized terpolymers were additionally studied via broadband dielectric spectroscopy. Constrained segmental dynamics was observed in the terpolymer containing the highest crystal fraction for which a narrow relaxation time distribution was found. Moreover, the enhanced dielectric and electromechanical response of DEHP doped terpolymer were interpreted via morphology microstructure and molecular mobility analysis. Interfacial polarization shifted to the high frequency by one decade because of dopant DEHP. Finally, electromechanical devices based on ferroelectric P(VDF-TrFE) and electrostrictive P(VDF-TrFE-CTFE) towards the dynamic force sensor implementation were designed and fabricated via inkjet printing technology. The bias electric field for terpolymer sensor was much lower than the poling electric field for a copolymer sensor. And the piezoelectric properties equivalent to the corresponding copolymer sensor can be obtained for a bias as low as 7.5 V/μ

Doctor of Philosophy / Food Science Institute / Edgar Chambers, IV / Three independent panels evaluated a total of 22 scents. Two panels were highly trained in sensory analysis techniques and performed descriptive analysis of the fragrances. In the third panel, 318 untrained respondents completed demographic questionnaires, personality tests, and surveys on fragrance attitudes and behaviors. They also evaluated the 22 scents: their perceptions of the fragrances’ sensory qualities and hedonic value were recorded, as well as the images and personalities they associated with these particular fragrances. Some methodological issues were tested, emphasizing the need for standardized procedures and consistency in fragrance evaluation. The use of consistent methodology in the preparation of fragrance samples is critical to accurately assess fragrance sensory properties. Additionally, consistent use of validated questionnaires constitutes an important strength for the fragrance industry: to better understand consumers, develop marketing strategies, and improve customers’ guidance and education. The interplay of individual differences with fragrance perception, whether from an attitudinal, sensorial, hedonic, or associative standpoint, appears complex. From a perceptual standpoint, sensory profiles generated by trained panels were representative of consumers’ perceptions, yet trained panelists discriminated better among fragrances and provided more detailed and actionable profiles. From an attitudinal and behavioral standpoint, demographic and psychological differences explained independent aspects of motivations and attitudes toward fragrances, but were not sufficient to fully account for the variability in attitudinal and behavioral patterns. Lastly, in terms of fragrance perception and image and personality associations, the combination of both intrinsic sensory characteristics and fragrance hedonic value was necessary to understand patterns of image and personality traits associated with fragrances. Interestingly, most findings were consistent even when individual differences in liking patterns for fragrances were taken into account. However, some specific dimensions, such as mood associations were preferred by clusters of respondents and depended upon individual differences. Although more research is needed to better understand the interrelationships among individual differences and all aspects of fragrance perception in real-life settings, this research provided valuable insights into these phenomena – insights that have direct implications, including understanding consumer perceptual processes, assessing potential influences of fragrances on social interactions, and providing strategic planning for marketing and advertising of personal fragrances.

Le principal objectif de cette thèse a été d'utiliser des outils numériques en sciences pour l'ingénieur dans le cadre d'applications médicales dont le but était de mieux appréhender la pathogénie des troubles fonctionnels, et de développer de nouvelles techniques thérapeutiques (sphère orofaciale). Dans un premier temps l'outil éléments finis s'appuyant sur des données rhéologiques a été utilisé afin de mieux appréhender la problématique de l'articulation temporo-mandibulaire. Les résultats numériques associés à une captation du mouvement de la mandibule ont permis de mieux comprendre, au sens, mécanique certains aspects mandibulaires. Par ailleurs, dans un deuxième temps, l'outil CAO a été mis en œuvre afin d'aider la préparation de la chirurgie maxillofaciale. Cette nouvelle approche a permis de mettre en œuvre une nouvelle méthodologie en chirurgie des tumeurs interruptrices en améliorant (i) le contrôle du résultat esthétique, (ii) la réduction du temps opératoire et (iii) le respect de la bonne congruence de l'ATM. / The main objective of this thesis was to use numerical engineering softwares in the framework of medical applications whose purpose was to understand the pathogenesis functional disorders, and to develop new therapeutic techniques (orofacial sphere). At first, finite elements tools based on rheological data has been used to understand the problem of TMJ. Numerical results associated with motion capture of the mandible have a better understanding the mandibular mechanical aspects. Moreover, in a second step, the CAD tools implemented to assist the preparation of the maxillofacial surgery. This new approach allowed a new methodology surgery interrupter tumors improving (i) controling the esthetic result, (ii) reducing the operating time and (iii) respecting a good TMJ congruence.

Due to the increasing demand from patients and dentists for highly aesthetic and strong, metal-free restorations there has been a rapid increase in research into dental CAD CAM technique and zirconia based restorations over the last decade. Such new technology has the potential to take the place of conventional techniques and materials for fabricating indirect dental restorations in the future. In this PhD thesis, five laboratory studies were designed to investigate zirconia bridges constructed using dental CAD CAM. The studies concentrated on: 1. Ideal force applied by dentists for cementing zirconia bridges and the impact on seating. 2. The effect of firing cycles and zirconia thickness on the fit of zirconia bridges. 3. The effect of span length on the fit of three and four unit all zirconia bridges. 4. The effect of veneering on the strength of three unit zirconia bridges. 5. The fit of three unit all zirconia bridges produced by digital and conventional techniques. For these laboratory studies an ideal three unit (and four unit for study 3) fixed-fixed all ceramic bridge preparation was carried out on two plastic teeth and all SLA models and zirconia based bridges were made using the Lava COS and Lava™ CAD CAM system (3M, ESPE). In addition to the laboratory studies, a clinical audit was carried out to assess satisfaction (dentist, dental technician and patient) with zirconia based restorations (through a xvi series of questionnaires) made and fitted at Dundee Dental Hospital and School. In addition, as part of this audit a simple cost analysis was carried out to explore the differences in cost between zirconia based restorations and high fusing gold alloy based metal ceramic restorations. Four of the studies (studies 1, 2, 3 and 5) investigated the internal and marginal fit of the zirconia based restorations under differing laboratory and clinical procedures and conditions. It was found that the seating force used to cement a zirconia based bridge had no impact upon fit (Study 1). Whilst the thickness of zirconia (all-zirconia bridge and un-veneered zirconia framework) did not affect the fit of the restoration, veneering the framework did lead to a statistically significant deterioration in fit (Study 2). Although leading to a poorer fit veneering did have a positive effect in strengthening the zirconia framework, but neither un-veneered nor veneered frameworks were as strong as monolithic/all zirconia bridges (Study 4). Despite the high shrinkage during post milling sintering and the potential for greater distortion on longer span bridges, the longer span bridges investigated in Study 3 did not impact upon fit. In study 1, 2, 3 and 4 the Lava COS intra-oral scanner was used to create a digital impression of the tooth preparations and study 5 confirmed that the fit of bridges made from these impressions were better than those made using conventional addition cured silicone putty and wash impressions (Study 5). The results of the questionnaires used in the audit revealed high satisfaction rates with all stake holders and the cost analysis showed that producing zirconia based restorations can be five to six times cheaper than conventional gold based restorations. Despite the variations in fit which were found in Studies 2 and 5, all bridges produced were within what would be regarded as clinically acceptable and comparable to those produced with more traditional techniques.

This research study examined what the motivations and consequences of self-disclosure on Instagram were as well as its correlation with Impression Management Theory. The research used a 37 question survey which was distributed on social media, through the Department of Media and Communication at ETSU as well as a public speaking class. There were 232 participants in this study who were 18 or older and used Instagram. Research found that individuals’ self disclose using levels of relationship management, showing off, information sharing and habitual behavior. Future research includes the opportunity to incorporate a sample of participants across different cultures to analyze the differences in self-disclosure styles on Instagram.

Les récents progrès dans le domaine des MEMS organiques suscitent un intérêt croissant dans la substitution de micropoutres inorganiques par des micropoutres organiques pour diverses applications. N’ayant été étudiée qu’en mode statique, la réponse électrostrictive des MEMS organiques est présentée pour la première fois en mode dynamique. L’une des originalités de ce travail est de fabriquer un micro-récupérateur d’énergie mécanique avec une approche « tout-organique ». Dans cette thèse, des matériaux nanocomposites à base d’oxyde de graphène réduit (rGO) dispersé dans du poly-dimethyl siloxane (PDMS), sont utilisés pour la récupération de l'énergie mécanique vibratoire avec une transduction électrostrictive. Le dispositif génère une densité de puissance électrique de 8,15 W/cm3 pour une accélération de 1 g au premier mode de résonance (≈ 17 Hz). / Recent advances in the field of organic MEMS have generated interest in the substitution of inorganic microbeams by organic ones for various applications. Until now, the use of electrostrictive materials is limited to the MEMS operating mostly in static mode. The electrostrictive response of organic MEMS is presented here for the first time in dynamic mode. One of the originality of this work is to produce a micro-mechanical energy harvester fabricated in an all-organic approach. In this thesis, strain sensitive nanocomposite materials based on reduced graphene oxide (rGO) dispersed in polydimethylsiloxane (PDMS) are used for mechanical vibratory energy harvesting with an electrostrictive transducer. With an acceleration of 1 g of the microcantilever base, actuation at the first resonant mode (≈ 17 Hz) generates an electrical power density of 8.15 μW/cm3.

Les substituts osseux synthétiques servent au remplacement temporaire des tissus osseux, favorisent la formation, la croissance et la survie de l’os et sont biorésorbables. Aucun matériau monophasé ne remplissant complètement ces exigences, un matériau composite bioinspiré est une alternative possible. L’objectif de cette thèse était par conséquent d’étudier la synthèse et les propriétés de deux composites biocéramiques/biopolymères : des hydrogels physiques de chitosane minéralisés avec de l’apatite, et une hardystonite architecturée imprégnée par des hydrogels physiques de chitosane. Afin d’obtenir le premier matériau, deux approches ont été développées. La première a consisté à fabriquer des hydrogels physiques de chitosane puis à les minéraliser avec de l’apatite ; la formation de microcapillaires se produit avec des conditions de synthèse spécifiques, et les précipités d’apatite ont été trouvés uniquement à la surface des hydrogels. La seconde approche consiste à convertir des suspensions homogènes contenant le phosphate de calcium et le chitosane en hydrogels de chitosane minéralisés par l’apatite. Les suspensions ont été préparées soit avec un mélange simultané, soit avec des mélanges successifs de suspensions phosphates de calcium avec les solutions de chitosane. Des agrégats minéraux plus petits avec une distribution plus uniforme ont été formés avec la méthode des mélanges successifs. Cela est attribué à une meilleure homogénéité, une viscosité plus faible et l’absence de chitosane. De manière générale, trois paramètres influencent les propriétés mécaniques d’hydrogels de chitosane minéralisés : la base utilisée pour la gélification (déterminant la vitesse de gélification : une grande vitesse conserve l’enchevêtrement des chaînes, résultant en une meilleure élasticité) ; la densité de la réticulation physique (cela induit un module de conservation plus important) et la force ionique (qui mène au désenchevêtrement des chaînes de chitosane, donc, à un faible module de conservation). Cette compréhension a permis l’utilisation de ces suspensions de phosphate de calcium-chitosane en tant qu’encre pour l’impression 3D. Les hydrogels de chitosane et les hydrogels minéralisés ne sont pas cytotoxiques. Pour fabriquer le second matériau, une encre pré-céramique a été imprimée en 3D puis frittée pour former une céramique d’hardystonite cristalline. Les scaffolds d’hardystonite ont été imprégnés par la solution de chitosane, converties ensuite en hydrogels physiques de chitosane. A plus forte concentration de chitosane, la viscosité de la solution était plus grande et l’imprégnation de la matrice plus lente. Avec une vitesse de gélification plus importante, qui dépend de la base utilisée pour la gélification, la perte de poids est plus faible pendant la gélification. L’hydrogel de chitosane a partiellement rempli les pores participant au support de charges externes et à la dissipation d’énergie par rupture. / Bone substitutes, an approach to attend social demand for bone healing and reparation, are temporary replacements of bone tissue, promote bone formation and growth and finally are bioresorbed. No single material meets these requirements; an alternative is a bioinspired composite material. The objective of this thesis was thus to study the synthesis and properties of two bioceramics/biopolymer composites: chitosan physical hydrogels mineralized with apatite and hardystonite scaffolds impregnated with chitosan physical hydrogels. To obtain the first material, two strategies were developed. The first one consisted in the fabrication of chitosan physical hydrogels and its subsequent mineralization with apatite; the formation of micro-capillaries occurred under particular synthesis conditions, and apatite precipitates were found only on the surface of hydrogels. The second strategy consisted in a simultaneous conversion of chitosan-calcium phosphate suspensions into chitosan-apatite hydrogels. The suspensions were prepared by sequential or simultaneous mixing of calcium and phosphate suspensions with chitosan solutions. Smaller and more uniformly distributed mineral aggregates were formed following sequential mixing, attributed to higher homogeneity, lower viscosity and no-presence of chitosan. This enabled the use of these chitosan-calcium phosphate suspensions as inks for 3-D printing. In general, three factors impacted the mechanical properties of mineralized chitosan hydrogels: the base used for gelation (determining the gelation rate: a higher rate preserved chain entanglement, resulting in higher elasticity); the density of physical crosslinks (hence a higher storage modulus) and the ionic strength (that led to chitosan chain disentanglements, thus, low storage modulus). Chitosan hydrogels and mineralized hydrogels were not cytotoxic, having no deleterious effects on osteoblasts proliferation. To fabricate the second material, pre-ceramic ink was 3-D printed and then sintered to form crystalline hardystonite ceramic. Hardystonite scaffolds were impregnated with chitosan solution that was, next, converted to chitosan physical hydrogel. At higher chitosan concentration, viscosity of solution was higher and scaffold impregnation was lower. At higher gelation rate, which depend on base used for gelation, lower weight loss during gelation. Chitosan hydrogel partially filled the pores contributing to bearing of external loads and to energy dissipated by fracture.

Le contexte actuel de forte croissance des besoins en énergie dans le monde nécessite une diversification de sa production, notamment vers des sources renouvelables tout en limitant autant qu’il est possible l’émission de gaz à effet de serre. Parmi les énergies renouvelables une des plus prometteuses et abondantes est l’énergie solaire et il apparaît évident que l’énergie solaire, thermique ou photovoltaïque, représente un enjeu crucial pour diminuer la consommation d’énergie fossile. Actuellement 90 % des générateurs solaires sont élaborés en silicium cristallin, ce qui pose un problème d’approvisionnement en matière première, les producteurs de silicium n’ayant pas su anticiper la forte expansion de la filière solaire. Des concepts innovants présentent une forte potentialité en termes de coût de production et d’application, notamment les filières organiques et hybrides (organique/oxyde métallique). En Europe, la France est très active dans ce domaine de recherche, en particulier en ce qui concerne l’utilisation de nouveaux matériaux nanostructurés organiques ou de structures hybrides. C'est pourquoi Disasolar, une start-up française spécialisée dans le photovoltaïque souple, souhaite développer cette activité en élaborant des modules solaires souples par impression jet d'encre. Les objectifs de cette thèse sont d'étudier des nouveaux matériaux d'interface imprimables et d'évaluer l'effet de la dimension des nanoparticules sur la topologie et les performances des dispositifs. Et dans un deuxième temps l'étude portera sur l'impression des matériaux d'interface et la stabilité des cellules solaires organiques. / The current context of strong growth in energy demands in the world requires diversification of its production, in particular towards renewable sources while limiting as far as possible the emission of greenhouse gases. Among the most promising and abundant renewable energies is solar energy and it is evident that solar, thermal or photovoltaic energy represents a crucial issue to reduce the consumption of fossil energy. Currently 90% of the solar generators are made of crystalline silicon, which poses a problem of supply of raw material, as silicon producers did not know how to anticipate the strong expansion of the solar sector. Innovative concepts present a high potential in terms of cost of production and application, in particular organic and hybrid (organic / metal oxide) dies. In Europe, France is very active in this area of research, particularly with regard to the use of new organic nanostructured materials or hybrid structures. This is why Disasolar, a French start-up specializing in flexible photovoltaics, wants to develop this activity by developing flexible solar modules by inkjet printing. The objectives of this thesis are to study new printable interface materials and to evaluate the effect of nanoparticle size on the topology and performance of devices. And secondly, the study will focus on the printing of interface materials and the stability of organic solar cells.