No description available.

No description available.

In this study, the tansparent conductive oxide (TCO) multilayer film AZO/Ag-Ti/AZO was fabricated with Ag-Ti alloy as conducting layer and AZO as anti-reflective material. The metal alloy was deposited by DC magnetron sputtering, and the AZO film deposition was performed by spin-coating technique and dried at suitable temperature. The thicknesses of Ag-Ti and AZO thin films were varied to fabricate AZO/Ag-Ti/AZO multilayer films. The microstructures of the multilayer films were observed by SEM and AFM. Sheet resistance was measured by using four-point probe. Optical transmittance was measured in the visible range by uv-vis spectrophotometer. The results show that as the top of AZO thickness is 50 nm, intermediate Ag-Ti metal laminated to 9 nm, and the bottom of the AZO is 35 nm, the transmittance of multilayer film AZO/Ag-Ti/AZO can reach 78.92%, and the sheet resistance is 1.86£[/¡¼. When thermal annealing process was carried out to the bottom AZO film, the worse characteristics of the transmittance and resistance of the performed multilayer film were resulted.

No description available.

No description available.

No description available.

Les films multicouches de polyélectrolytes sont des auto-assemblages de polymères chargés formant des films dont l'épaisseur peut être variée de quelques nm à quelques µm. Un nombre croissant de travaux concerne la compréhension de leur mécanisme d'auto-assemblage et leur utilité pour modifier les propriétés physico-chimiques, topographiques ou mécaniques de surface de (bio)matériaux. Dans cette thèse, nous avons étudié les propriétés de films à base de poly(L-lysine) et de polysaccharides connus pour leur rôle physiologique, notamment le hyaluronane, la chondroïtine sulfate et l'héparine. Les compositions internes de ces films mono-constituants ou à base de mélanges de polyélectrolytes ont été sondées. L'influence de la chimie des polyélectrolytes sur la formation des films, en particulier l'importance des groupements sulfates, a été mise en évidence. Leur potentiel comme vecteur de délivrance d'un facteur de croissance, la BMP-2, a été évalué. De fortes quantités de BMP-2 ont pu être chargées dans les films à base de hyaluronane. Nous avons pu contrôler les quantités insérées en faisant varier la composition chimique des films, leur épaisseur ou la concentration en BMP-2 de la solution de chargement. Puis nous avons mis en évidence une différenciation contrôlée de façon dose-dépendante de cellules C2C12 pluripotentes sur les films bioactifs : différenciation myogénique (en absence de facteur) ou ostéoblastique. De plus, nous montrons qu'un contact des cellules avec le film bioactif est nécessaire pour induire leur différenciation. La protéine est donc présentée par « la phase solide », ce qui constitue un mode de présentation du facteur proche des conditions physiologiques. Des résultats préliminaires obtenus en recouvrant des biomatériaux orthopédiques par les films bioactifs laissent penser que ces films offrent des perspectives intéressantes dans le domaine de la régénération osseuse in vivo. / Polyelectrolyte multilayer films are self-assembled architectures forming nm to µm thick films. During the last decade, they have emerged as an efficient way of modifying materials surface properties such as chemistry, physico-chemical properties, topography as well as mechanical properties. Thanks to the technology's versatility and ease of use, polyelectrolyte multilayer films are now recognized as a new tool for modifying biomaterial surfaces and mediating cell behaviours and implant bio-integration. In this thesis, we studied the properties of poly(L-lysine) and polysaccharide-based multilayer films and focused on their physical-chemical properties as well as on their internal composition. In particular, we studies the influence of their chemistry (presence of carboxylic or sulfate groups) on film formation and characteristics. Three polysaccharides with increasing sulfate group content were chosen for this purpose: hyaluronan, chondroitin sulfate and heparin. The capacity of these films to act as a drug delivery vehicle for BMP-2 (a growth factor able to induce osteo-differentiation) was then assessed. High BMP-2 amounts were successfully loaded and retained in the films in a controlled manner. The loaded amounts could be modulated by varying the film's chemistry, film thickness or BMP-2 concentration in the loading solution. We showed that it is possible to control the extent of C2C12 cell differentiation in osteoblasts when cultured on the bioactive films. Importantly, when no BMP-2 is loaded in the films, the cells differentiated in to myotubes, their most common differentiation pathway. Cells needed a direct contact with the bioactive films to respond to BMP-2, suggesting that BMP-2 is mainly presented to the cells from the solid phase. Preliminary in vivo tests on film-coated orthopaedic biomaterials are encouraging. They showed that these films are interesting candidates for surface modification of orthopaedic biomaterials and may foster bone regeneration.

Chapas multicamadas são comumente utilizados em embalagens de produtos industrializados, tendo como função básica conter, proteger e apresentá-los de maneira atrativa ao consumidor final. Os polímeros utilizados para produzir estas chapas devem possuir boas propriedades de barreira para melhor conservação dos produtos e podem ser produzidos através dos processos de co-extrusão e laminação. Uma das formas de conversão das chapas multicamadas em embalagens é o processo de termoformagem, que permite a produção de embalagens em diferentes formatos. Na indústria farmacêutica e agroquímica algumas vezes é necessário o desenvolvimento de produtos a base de solventes agressivos, e com isso a avaliação da resistência química do polímero da embalagem em contato com o produto constitui-se uma ferramenta importante. Para analisar a degradação do material da embalagem podem ser utilizadas as técnicas de termogravimetria (TG), Calorimetria Diferencial de Varredura (DSC) e microscopia eletrônica de varredura (MEV), Espectroscopia de Absorção no Infravermelho por Transformada de Fourier (FT-IR) e Difração de Raios X (DRX). Neste artigo são apresentados os resultados dos estudos de envelhecimento de chapas multicamadas de PE/EVOH/PE + PP/COC (Copolímeros de ciclo-olefina) /PP com exposição aos solventes DMSO e N-meitl-2-pirolidona nas condições ambientais de 30°C/ 75% UR e de 40°C/ 75% UR. O resultado do estudo indica que as técnicas de FT-IR por ATR, DRX e MEV podem auxiliar no acompanhamento do envelhecimento de chapas multicamadas e indicaram que as chapas possuem desempenho bom na situação avaliada. / Multilayer sheets films are used in industrial packaging products, with the basic function contain, protect and present them in attractive way to the final consumer. The polymers used to produce these plates should have good barrier properties and a better conservation of the products may be produced by co-extrusion and lamination processes. One way of converting the multilayer sheet packaging is the thermoforming process that allows the production of different packaging formats. In the pharmaceutical and agrochemical industry is sometimes necessary to develop products to aggressive solvent-based, and thus the assessment of the chemical resistance of the polymer of the packaging in contact with the product constitutes an important tool. To analyze the degradation of the packaging material may be used thermogravimetric technique (TG), Differential Scanning Calorimetry (DSC) and scanning electron microscopy (SEM), Absorption Infrared Spectroscopy Fourier Transform (FT-IR) and X-Ray Diffraction (XRD). This article presents the results of aging studies of multilayer sheets of PE / EVOH / PE + PP / COC (cyclic olefin copolymers) / PP with exposure to DMSO solvents and N-2-pyrrolidone-meitl environmental conditions 30°C / 75% RH and 40°C / 75% RH. The result of the study indicates that the FT-IR techniques for ATR, XRD and SEM can assist in monitoring the aging of multilayer plates and indicated that the plates have good performance in the situation assessed.

In this study we fabricated free standing multilayer films of polyelectrolyte complexes for potential use in tissue engineering of corneal stroma by using the layer-by-layer (LbL) approach. In the formation of these LbL films negatively charged, photocrosslinkable (methacrylated) hyaluronic acid (MA-HA) was used along with polycations polyethyleneimine (PEI) and poly(L-lysine) (PLL). Type I collagen (Col) was blended in with PLL for improving the water absorption and cell attachment properties of the films. It was shown that the LbL films could be easily peeled off from glass substrates due to the photocrosslinking of one of the LbL components, the hyaluronic acid. Film growth and composition were monitored with FTIR-ATR. Heights of peaks at 3383 cm-1, and 2958 cm-1increased along with the bilayer number confirming the polymer build-up. Film integrity and thickness were investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Films thicker than 5 bilayers (BLs) were found to be uniform in appearance and 10 BL (PEI/MeHA) films were calculated to be ca. 6 &mu / m thick. Atomic force microscopy (AFM) revealed that as the number of BLs increased, surface roughness decreased. Activity of methacrylated hyaluronic acid was shown by the increased resistance of photocrosslinked multilayer films against hydrolysis by hyaluronidase. Patterns could be created on the films by photocrosslinking further proving that the crosslinking step is successful. Since the ultimate goal was to construct a corneal stroma PEI/MA-HA films were tested with corneal stroma cells, keratocytes. Cell proliferation on PEI/MA-HA films was quite poor in comparison to TCPS. In order to improve the cell adhesion the tests were repeated with PLL/MA-HA. Collagen was added to decrease the hydrophilicity and introduce cell adhesion sequences (Arg-Gly-Asp, RGD) to improve cell proliferation on the films and thus PLL+Col/MA-HA films were also tested. Introduction of collagen to the PLL/MA-HA films was found to decrease water retention of the multilayer films and improve cell viability and proliferation. Col+PLL/MA-HA LbL thus appear to be a promising platform for tissue engineering, especially of corneal stroma.

Chapas multicamadas são comumente utilizados em embalagens de produtos industrializados, tendo como função básica conter, proteger e apresentá-los de maneira atrativa ao consumidor final. Os polímeros utilizados para produzir estas chapas devem possuir boas propriedades de barreira para melhor conservação dos produtos e podem ser produzidos através dos processos de co-extrusão e laminação. Uma das formas de conversão das chapas multicamadas em embalagens é o processo de termoformagem, que permite a produção de embalagens em diferentes formatos. Na indústria farmacêutica e agroquímica algumas vezes é necessário o desenvolvimento de produtos a base de solventes agressivos, e com isso a avaliação da resistência química do polímero da embalagem em contato com o produto constitui-se uma ferramenta importante. Para analisar a degradação do material da embalagem podem ser utilizadas as técnicas de termogravimetria (TG), Calorimetria Diferencial de Varredura (DSC) e microscopia eletrônica de varredura (MEV), Espectroscopia de Absorção no Infravermelho por Transformada de Fourier (FT-IR) e Difração de Raios X (DRX). Neste artigo são apresentados os resultados dos estudos de envelhecimento de chapas multicamadas de PE/EVOH/PE + PP/COC (Copolímeros de ciclo-olefina) /PP com exposição aos solventes DMSO e N-meitl-2-pirolidona nas condições ambientais de 30°C/ 75% UR e de 40°C/ 75% UR. O resultado do estudo indica que as técnicas de FT-IR por ATR, DRX e MEV podem auxiliar no acompanhamento do envelhecimento de chapas multicamadas e indicaram que as chapas possuem desempenho bom na situação avaliada. / Multilayer sheets films are used in industrial packaging products, with the basic function contain, protect and present them in attractive way to the final consumer. The polymers used to produce these plates should have good barrier properties and a better conservation of the products may be produced by co-extrusion and lamination processes. One way of converting the multilayer sheet packaging is the thermoforming process that allows the production of different packaging formats. In the pharmaceutical and agrochemical industry is sometimes necessary to develop products to aggressive solvent-based, and thus the assessment of the chemical resistance of the polymer of the packaging in contact with the product constitutes an important tool. To analyze the degradation of the packaging material may be used thermogravimetric technique (TG), Differential Scanning Calorimetry (DSC) and scanning electron microscopy (SEM), Absorption Infrared Spectroscopy Fourier Transform (FT-IR) and X-Ray Diffraction (XRD). This article presents the results of aging studies of multilayer sheets of PE / EVOH / PE + PP / COC (cyclic olefin copolymers) / PP with exposure to DMSO solvents and N-2-pyrrolidone-meitl environmental conditions 30°C / 75% RH and 40°C / 75% RH. The result of the study indicates that the FT-IR techniques for ATR, XRD and SEM can assist in monitoring the aging of multilayer plates and indicated that the plates have good performance in the situation assessed.