Uran kann sowohl durch geogene als auch anthropogene Vorgänge in die Umwelt gelangen. Dazu zählen natürliche Uranerzvorkommen und deren Leaching sowie die Auswaschung von Uran aus den Hinterlassenschaften des ehemaligen Uranerzbergbaus. Die Aufklärung des Verhaltens von Uran in der Geo- und Biosphäre ist für eine Risikoabschätzung des Migrationsverhaltens von Radionukliden in der Umwelt notwendig. Algen sind in der Natur weit verbreitet und die wichtigste Organismengruppe in den aquatischen Lebensräumen. Durch ihre ubiquitäre Verbreitung in der Natur ist ihr Einfluss auf das Migrationsverhalten von Uran in der Umwelt von grundlegendem Interesse z.B. um effektive und wirtschaftliche Remediationsstrategien für Wässer zu entwickeln. Außerdem stehen Algen am Beginn der Nahrungskette und spielen eine wirtschaftlich relevante Rolle als Nahrung beziehungsweise Nahrungsergänzungsmittel. Die Möglichkeit des Transfers von algengebundenem Uran entlang der Nahrungskette könnte eine ernsthafte Gesundheitsgefahr für den Menschen darstellen. Das Ziel dieser Arbeit war die quantitative und strukturelle Charakterisierung der Wechselwirkung zwischen Uran(VI) und der Grünalge Chlorella vulgaris im umweltrelevanten Konzentrations- und pH-Wertbereich unter besonderer Berücksichtigung der Stoffwechselaktivität. Die in dieser Arbeit erzielten Ergebnisse der Sorptionsexperimente zeigen deutlich den maßgeblichen Einfluss des Stoffwechselstatus von Chlorella auf die Wechselwirkung mit Uran. So kann in Gegenwart von umweltrelevanten Urankonzentrationen eine Remobilisierung von zuvor passiv gebundenem Uran durch die stoffwechselaktiven Algen erfolgen. Die in Abhängigkeit von der Stoffwechselaktivität, der Urankonzentration und dem pH-Wert mit den Algenzellen gebildeten Uran(VI)-Komplexe wurden strukturell mit Hilfe der spektroskopischen Methoden TRLF-, EXAFS- und ATR-FTIR-Spektroskopie charakterisiert. Mittels TEM konnte Uran in Form von 30-70 nm großen nadelförmigen Ablagerungen in der Zellwand der lebende Algenzellen nachgewiesen werden. Die in dieser Arbeit erhaltenen Ergebnisse leisten einen wichtigen Beitrag zur Vorhersage des Migrationsverhaltens von Uran unter umweltrelevanten Bedingungen und der radiologischen Risikobewertung von geogen und anthropogen auftretendem Uran.

Die Schwingungsspektroskopie, besonders die Raman-Spektroskopie, stellt ein wichtiges Werkzeug für Untersuchungen von Biomineralien dar. Raman-Spektroskopie wurde zur Untersuchung der organischen und anorganischen Bestandteile von Schwammskeletten eingesetzt. Die Raman-Spektroskopie trug auch zur Charakterisierung von biomimetischen Silikat-Präzipitaten bei. Durch ortsaufgelöste Raman-Spektroskopie konnte erstmalig die Verteilung von organischem Material in den extrahierten Silikatzellwänden von Kieselalgen nachgewiesen werden. Die ortsaufgelöste Raman-Spektroskopie wurde ebenfalls zur Untersuchung des SERS-Effekts an Zellwänden von Kieselalgen an die Silber-Nanopartikel gekoppelt waren eingesetzt.

Mikroplastik (Kunststoff-Partikel < 5 mm) wurde in den vergangenen Jahren vermehrt in verschiedenen marinen Ökosystemen nachgewiesen und erreicht regelmäßig wissenschaftliche und öffentliche Aufmerksamkeit. Es wird als potentielle Gefahr für die marine Umwelt angesehen. Aufgrund der geringen Größe kann Mikroplastik von marinen Organismen mit der Nahrung verwechselt werden und infolge dessen in den Magen-Darm-Trakt gelangen. Ob die so aufgenommenen Partikel zu einer Schädigung der Organismen führen und welche Wirkungsmechanismen dabei eine Rolle spielen, ist derzeit noch nicht umfassend geklärt. In diesem Zusammenhang wird Mikroplastik beispielsweise als Transportvehikel für enthaltene Kunststoffadditive, für adsorbierte persistente organische Schadstoffe sowie für potentiell pathogene Mikroorganismen diskutiert. Für eine Risikobewertung sind in erster Linie zuverlässige Daten über die Mikroplastik-Gehalte in verschiedenen Umweltkompartimenten nötig. Dazu werden geeignete und sichere analytische Verfahren zur Identifizierung und Quantifizierung von Mikroplastik in Umweltproben benötigt. Ziel dieser Arbeit war es bestehende Wissenslücken im Bereich der Mikroplastik-Analytik zu schließen und Möglichkeiten und Grenzen der FTIR- und Raman-Spektroskopie für die analytische Untersuchung von marinen Mikroplastik-Proben aufzuzeigen. Dazu wurde zunächst ein Filtersubstrat entwickelt, das für eine umfassende Untersuchung von filtrierten Mikroplastik-Proben sowohl mittels Transmission FTIR- als auch mittels Raman-Mikroskopie geeignet ist. Des Weiteren wurde Raman Imaging als neuartige Methode zur Identifizierung von Mikroplastik etabliert und hinsichtlich verschiedener Messparameter optimiert. Die Anwendbarkeit dieses neuen Analyseansatzes wurde an realen Umweltproben gezeigt. Beide spektroskopische Verfahren (IR und Raman) wurden anhand von Modellproben und realen Umweltproben miteinander verglichen und validiert. Zusätzlich dazu wurden die spektroskopischen Ergebnisse an ausgewählten Proben mit der thermoanalytischen py-GC/MS-Methode verglichen und beurteilt. Im dritten Teil der Arbeit wurden die Mikroplastik-Gehalte in Sedimentproben aus dem Mündungsbereich der Warnow, einem bedeutenden Zufluss zur Ostsee, bestimmt. Dabei wurden lokale Eintragspfade abgeschätzt sowie Senke von Mikroplastik identifiziert.:1 Motivation und Zielstellung 2 Wissenschaftlicher Hintergrund 3 Experimenteller Teil 4 Ergebnisse und Diskussion 5 Zusammenfassung und Ausblick Anhang Literaturverzeichnis Abbildungsverzeichnis Tabellenverzeichnis Danksagung Publikationsliste Versicherung

Lubricant is a common name for a large group of products that are essential for almost every engine or other machinery equipment that include mechanical part movements. Their main application is reduction of the friction between two rubbing surfaces by interposing a lubricating film between them. Other important functions of lubricants beside lubrication are; heat transfer, energy efficiency enhancement, corrosion and oxidation protection. All types of lubricants mainly consist of base oil and additives. Base oils are mainly hydrocarbon compounds, while additives are various chemical compounds added to the base oil to enhance some of the already existing properties, or to impose new properties that are beneficial for application purposes. During the storage period, where different storage conditions can occur, many of the requirements for lubricants chemical and physical stability needs to be fulfilled. Inappropriate storage conditions can cause physical and chemical changes in lubricants, which can make them unusable for the intended application. The effects of different storage conditions on lubricants stability were investigated in this work. The experimental part of this project was conducted at Fuchs Lubricants Sweden AB. At the beginning of the experiment, twelve 2L high density polyethylene bottles (HDPE) filled with the lubricant, were divided into three groups. The first group consisted of four closed HDPE bottles previously filled with the lubricant that were stored at 9 °C, 22 °C, 45 °C and 80 °C. The second and the third group consisted also of four open bottles and four bottles with added distilled water stored at the same storage temperatures. The amount of lubricant was approximately the same in all bottles. At different time intervals sample aliquots from the top, middle and the bottom layer were taken from these bottles and analyzed. The effects of different storage conditions on the lubricant’s stability and homogeneity were acquired by two distinctive spectroscopic methods. Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) was used for elemental composition analysis, while the Fourier Transform Infrared (FTIR) Spectroscopy was used for evaluation of chemical changes on molecular level. Results from ICP-AES analyses showed almost homogeneous elemental distribution, virtually unaffected by different storage conditions in all sample bottles. Results from FTIR analyses showed that observed changes in absorption peaks (673, 863, 972. and 1267 cm-1) took place almost simultaneously at all three layers in all bottles stored at four different temperatures. These results suggest that the analyzed lubricant was stable and homogeneous for the observed period. The lowest storage temperature caused minimal changes in the lubricant and can be considered as optimal storage temperature for this product. It was also observed that increased temperature, direct exposure to oxygen and presence of water catalytically affected the rate of these changes. A part of this project was to validate the method used for ICP analysis. For this purpose, the following method performance parameters were investigated: linearity, precision, accuracy, Limit of detection (LOD) and Limit of quantification (LOQ). The obtained results showed that linearity of the method for all elements, in the used standard, was confirmed based on the set criteria. Precision and accuracy were tested in repeatability conditions and at four different concentration levels. The obtained results showed that accuracy of the method increased with concentration, and was highest for 50 ppm, for almost all elements. The highest precision (&lt; 2 % RSD), for almost all elements was obtained for the concentration of 25 ppm. The LOD values were between 0.01 and 1.42 ppm while calculated LOQ values were between 0.04 and 4.73 ppm. / Smörjmedel är det gemensamma namnet för en stor produktgrupp som är nödvändig för nästan alla motorer eller annan maskinutrustning som inkluderar mekaniska delrörelser. Deras huvudsakliga tillämpning är att minska friktionen mellan två ytor i rörelse genom att införa en smörjfilm mellan dem. Andra viktiga funktioner förutom smörjning är; värmeöverföring, energieffektivisering, korrosion-och oxidationsskydd. Alla typer av smörjmedel består huvudsakligen av basolja och tillsatser. Basoljor är huvudsakligen kolväteföreningar medan tillsatser är olika kemiska föreningar som läggs till basoljan för att förbättra några av de befintliga egenskaperna eller att införa nya egenskaper som är fördelaktiga för applikationsändamål. Under lagringsperioden, där olika lagringsförhållanden kan uppstå, måste många av kraven på smörjmedlens kemiska och fysikaliska stabilitet uppfyllas. Olämpliga lagringsförhållanden kan orsaka fysiska och kemiska förändringar i smörjmedlen som kan göra dem oanvändbara för avsedd användning. Effekterna av olika lagringsförhållanden på smörjmedelstabilitet undersöktes i detta arbete. Experimentell del av detta projekt genomfördes hos Fuchs Lubricants Sweden AB. I början av experimentet, tolv 2L högdensitetspolyetenflaskor (HDPE) fyllda med smörjmedlet, uppdelades i tre grupper. Den första gruppen bestod av fyra slutna HDPE-flaskor som ifylldes med smörjmedlet och som lagrades vid 9 ° C, 22 ° C, 45 ° C och 80 ° C. Den andra och den tredje gruppen bestod också av fyra öppna flaskor och fyra flaskor med tillsatt destillerat vatten lagrat vid samma lagringstemperaturer. Mängden av smörjmedel var ungefär lika i alla flaskor. Vid olika tidpunkter togs prov från topp-mitten-och bottenskiktet från dessa flaskor och analyserades. Effekterna av olika lagringsförhållanden för smörjmedelsstabiliteten och homogeniteten förvärvades genom två distinkta spektroskopiska metoder. Induktivt kopplad plasma atomemissions-spektroskopi (ICP-AES) användes för elementsammansättningsanalys medan Fourier transform infraröd spektroskopi (FTIR) användes för utvärdering av kemiska förändringar på molekylär nivå. Resultat från ICP-AES-analyser visade nästan homogen fördelning av element, opåverkad av olika lagringsförhållanden i alla provflaskor. Resultat från FTIR-analyser visade att observerade förändringar i absorptionstoppar (673, 863, 972 och 1267 cm-1) inträffade nästan samtidigt i alla tre skikten i flaskorna lagrade vid fyra olika temperaturer. Dessa resultat tyder på att det analyserade smörjmedlet var stabilt och homogent under den observerade perioden. Den lägsta lagringstemperaturen orsakade minimala förändringar i smörjmedlet och kan betraktas som den optimala lagringstemperaturen för denna produkt. Resultatet visade också att ökad temperatur, direkt exponering för syre och närvaro av vatten hade katalytiskt påverkat graden av dessa förändringar. En del av detta projekt var att validera metoden som används för ICP-analys. För detta ändamål undersöktes följande metodprestanda-parametrar: linjäritet, precision, noggrannhet, detektionsgräns (LOD) och kvantifieringsgräns (LOQ). De erhållna resultaten visade att linjäriteten för metoden, för alla element, i den använda standarden bekräftades baserat på uppsatta kriterier. Precision och noggrannhet testades i repeterbarhetsförhållanden och vid fyra olika koncentrationsnivåer. De erhållna resultaten visade att metodens noggrannhet ökade med koncentration och var högst för 50 ppm, för nästan alla element. Den högsta precisionen (&lt;2% RSD), för nästan alla element, erhölls för koncentrationen av 25 ppm. LOD-värdena var mellan 0.01 och 1.42 ppm medan beräknade LOQ-värden var mellan 0.04 och 4.73 ppm.

To decrease the environmental footprint, the textile industry needs to become more circular. One company that is trying to close the textile lifecycle loop is the Swedish company Renewcell. In the Renewcell process, discarded clothes and other textile waste are turned into a dissolving pulp that can be used for production of new textiles. For this to work, it is important to generate a non-colored dissolved pulp. Therefore, it is of great interest to be able to optimize the bleaching process and evaluate different starting materials. Today, there are different methods that have been used for quantification of specific dyes and for identification of raw materials in textiles. However, there is no complete method that can be used for all types of dyes and raw materials. This master thesis will therefore investigate the bleaching step and the raw materials used in Renewcell’s recycling process. The aim with this project is to develop a method, to be able to analyse the presence of dyes qualitatively and quantitatively in the dissolved pulp from the recycled cotton-based textiles. To do so, different chemical analysing methods were used. These include kappa number measurements, UV-VIS and FTIR. Nine different types of jeans, one yarn, three raw materials (cotton, PET and elastane), and two pure dyes (indigo and black sulfur dye) were selected for this project. The result from the kappa number measurements shows that only the blue jeans, blue yarn and black jeans could be bleached and measured by using the original kappa number method at 25 degrees C. But when the same procedure was done manually and the temperature was increased to 70 degrees C, almost all materials could be bleached and measured. Therefore, the conclusion is that this method can be a successful quantification method. However, the temperature correction equation needs to be developed further to be able to quantify the exact amount of dyes. The kappa number was also compared with the absorbance factor, i.e. the k-value from the UV-VIS results. A correlation could be seen for the blue jeans, blue yarn, and black jeans. So, the UV-VIS method could also be a possible method for quantification of dyes in textiles. For the qualitative analyses, FTIR was used. The results showed that the raw materials could be identified by comparing the resulting FTIR spectra with a reference spectrum. For the jeans and yarn materials, indigo dye was identified for the blue jeans, blue yarn, and black jeans. However, for the other materials, the amount of dyes was too low to be able to draw conclusions about the chemical structure. With further development, these methods could be used as successful qualitative and quantitative methods for analysing dyes in textiles. This would generate positive consequences in several ways. The usage of bleaching chemicals could be optimized, and the quality of the final textile material could be improved. This would benefit both the manufacturer of these recycled textiles (economically) and the consumer who will buy the final product (quality). Indirectly, this would help to decrease the environmental footprint from the textile industry.

Mikroplastik (1–1000 µm) kommt praktisch überall in der Umwelt vor, aber immer noch ist die Iden-tifizierung und Quantifizierung eine anspruchsvolle und zeitintensive Aufgabe. Erste analytisch Metho¬den beginnen sich zu etablieren, jedoch sind die benötigten Instrumente komplex und der Probendurchsatz für Routineuntersuchungen in den meisten Fällen noch zu gering. Diese Arbeit widmet sich zunächst dem Potenzial der Nahinfrarot (NIR)-Spektroskopie diese Lücke zu schließen. Exemplarisch wird ein günstiges Verfahren mit großem Probendurchsatz zur Bestimmung von Mikro¬plastik-Gesamtgehalten der verbreiteten Verpackungskunststoffe Polyethylen (PE), Polystyrol (PS) und Polypropylen (PP) in Böden und Kompost entwickelt. Neben der Untersuchung von Mikroplastik-Gesamtgehalten einer Probe ist auch die Charakterisierung individueller Partikel von großer Bedeutung. Die bildgebende Fourier-Transform-Infrarot (FTIR)-Mikrospektroskopie ist hierfür sehr gut geeignet. Allerdings ist es eine Herausforderung Mikroplastik in den aus mehreren Million Spektren bestehenden hyperspektralen Bildern zu identifizieren. Eine schnelle und zuverlässige Mikroplastikerkennung wird hier durch eine explorative Analyse und automatisierte Klassifizierung der Spektren erreicht. Zusammenfassend zeigt diese Arbeit, dass die optische Spektroskopie im mittleren und nahen Infrarot über ihre bisherige Anwendung hinaus ein großes Potenzial besitzen, die Mikroplastik-Analytik kostengünstiger, einfacher und schneller zu gestalten. / Microplastics (1-1000 µm) are ubiquitous in the environment, but their identification and quantification is still a challenging and time-consuming task. The first established methods require complex instruments and the sample throughput is still too low for routine analysis in most cases. This work first addresses the potential of near-infrared (NIR) spectroscopy to fill this gap. A low-cost method with large sample throughput is developed for the determination of total microplastic contents of the common packaging plastics polyethylene (PE), polystyrene (PS) and polypropylene (PP) in soils and compost. In addition to the investigation of total microplastic levels in a sample, the characterization of individual particles is also of great importance. Fourier transform infrared (FTIR) imaging microspectroscopy is well suited for this purpose. However, it is challenging to identify microplastics in hyperspectral images consisting of several million spectra. Fast and reliable microplastic detection is achieved by exploratory analysis and automated classification of the spectra. In summary, this work shows that mid- and near-infrared optical spectroscopy have great potential beyond their current application to make microplastics analysis cheaper, easier, and faster.

Plast påverkar vårt samhälle i stor utsträckning och har hjälpt till att utveckla nya förbättringar och redskap i vår vardag. Trots alla bra egenskaper med plaster har några oönskade effekter kommit till ytan med negativ påverkan på miljön. Detta examensarbete undersökte hur plastmaterial bryts ned av vittring utanför den svenska västkusten. Plastmaterialen undersöktes med hjälp av Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) och Scanning Electron Microscopy (SEM) för att fastställa om kemisk nedbrytning sker efter 12 månader. Följande frågor stod i fokus: Vilka plaster har brutits ned, och i vilken utsträckning? Hur har plastens egenskaper förändrats? Vilka förutsättningar har de olika plastmaterialen för nedbrytning på stränder, och vilka faktorer påverkar nedbrytningen? Resultatet indikerade att liten eller ingen detekterbar nedbrytning skett på proverna efter 12 månaders vittring genom FTIR analys. Några prover visade dock tecken på förändring i de fysiska egenskaperna vid DSC analys, vilket kan beror på nedbrytning. Trots detta resultat fanns det synliga tecken på fragmentering, fysisk skada från stress och yttre krafter, såsom sand- och vågtumling för EPS (Styrofoam), LD-PE (Candy Paper) och PP (Blårep). Fragmenteringens påverkan på havlsmiljön kunde dock inte bevisas i denna studie eftersom prover på sand eller vatten från området inte genomfördes. Detta gör att endast synliga indikationer på fragmentering var identifierbara, men inte bevisa att det bidragit till makro- eller mikroplaster i närmiljön. Samtliga plastmaterial i studien innehöll någon form av tillsatts så som stabilisatorer. Eftersom endast små variationer förekommer i analysen av plastmateralen kunde det antas att tillsatserna och stabilisatorerna i materialen var effektiva i att hindra polymererna från nedbrytning under 12-månaders vittring. / Plastic has greatly impacted our society today and helped develop new improvements and implements in the daily lives. Despite all the good things, some undesirable impacts have also been discovered, which have been shown to impact the climate negatively. This thesis was to investigte how plastic degrades when weathered outside the  Swedish West Coast. The plastic materials were analysed using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) to determine whether degradation had occurred after 12 months. The following questions were at focus: What plastics have been degraded, and if so, which to the greatest extent? How have the properties of the plastic changed? What were theprerequisites for the different plastic materials for degradation on the shoreline, and what factors are affecting the degradation? The results indicated that the samples had little to no detectable degradation regarding the FTIR analysis after 12 months of weathering. Some of the samples showed a change in the physical properties from the DSC analysis, which could indicate degradation. Despite the result of degradation extent, there were clear signs of fragmentation, physical damage from stress, and external forces, such as rock and wave tumbling for EPS (Styrofoam), LD-PE(Candy Paper) and PP (Blue Rope). Fragmentation was not proven since no soil or water samples were made at the wethering site. This made the fragmentation only a visible parameter based on the samples after weathering, not proving that micro- or macro-plastic has been washed out in the ocean. All of the plastic materials used in the study were produced with some sort of additive, such as stabilisers. Since only small variations were shown in the analysis of the plastic materials, it can be assumed that additives and stabilisers were effective because there was no clear sign of degradation after 12 months of weathering.

Disease- and drug-related bone disorders are rapidly increasing in the population. The drugs which are used for the treatment of neurodegenerative diseases and metabolic derangements, may have negative or positive effects on bone tissues. In the first study, the possible side-effects of Carbamazepine and epileptic seizures on bone structure and composition were investigated by FTIR and synchrotron-FTIR microspectroscopy, AFM and micro- and nano-hardness analysis. The effects on the blood parameters, bone turnover and vitamin D metabolism were also investigated by ELISA and western blot analysis. The current study provides the first report on differentiation of the effects of both epileptic seizures and AED therapy on bones. Besides Carbamazepine treatment, seizures also caused a decrease in the strength of bone. The biochemical data showed that both the epileptic and drug-treated groups decreased vitamin D levels by increasing the vitamin D catabolism enzyme / 25-hydroxyvitamin D-24-hydroxylase. In the second study, the possible pleiotropic (positive) effects of cholesterol lowering drug / Simvastatin on bones were investigated by ATR-FTIR spectroscopy. The current study provides the first report on dose-dependent effects of simvastatin on protein structure and lipid conformation of bones. ATR-FTIR studies showed that although both high and low dose simvastatin strengthen bones, low dose simvastatin treatment is much more effective in increasing bone strength. Neural network analysis revealed an increased antiparallel and aggregated beta sheet and random coil in the protein secondary structure of high dose group implying a protein denaturation. Moreover, high dose may induce lipid peroxidation which limit the pleiotropic effects of high dose treatment on bones. This study clearly demonstrated that using low dose simvastatin is safer and more effective for bone health than high dose simvastatin treatment.

Over the last decades organic light-emitting diodes (OLEDs) and organic solar cells (OSCs) have gained considerable attention as efficient, flexible, lightweight, and potentially low-cost technology for lighting and display applications or as a renewable energy source, respectively. However, achieving long-term stability remains challenging. Revealing and understanding aging processes is therefore of great interest. This work presents fundamental investigations to understand and circumvent organic device degradation. In the first part, single materials used in organic devices were investigated. By tailoring an attenuated total reflection infrared (ATR-IR) spectrometer to the specific needs and subsequent measurements, it is shown that the tris(8-hydroxyquinoline)aluminum (Alq3) molecule, a well known fluorescent green emitter, degrades during air exposure by the formation of carbonyl groups. By using a laser desorption/ionization time of flight mass spectrometer (LDI-TOF-MS) it was shown that a,w-bis-(dicyanovinylen)-sexithiophen (DCV6T-Bu4), a well known small-molecule material which is used as part of the active layer, reacts with oxygen during ultraviolet (UV) irradiation. By using climate boxes and a sun simulator the impact of dry and humid air as well as sunlight on C60, a widely-used acceptor molecule in organic solar cells, was investigated. The breaking of the C60 cage to C58 and C56 and the further reaction of these components with oxygen as well as the dimerization of C58 and C56 molecules were found. The degradation products such as C58O increase with air exposure time but they are independent of the humidity level of the ambient air as well as sunlight irradiation. Subsequent annealing leads to a decrease of the C58O concentration. Many efficient n-dopants are prone to degradation in air, due to the low ionization potentials, thereby limiting the processing conditions. It was found that the air exposure of the highly efficient n-dopant tetrakis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinato)ditungsten(II) (W2(hpp)4) leads to oxidation reactions of the molecule to [W(hpp)2 + O] and other degradation products. The decay constant of W2(hpp)4 and the matching mean growth time of the [W(hpp)2 + O] degradation as well as a second very quick degradation of the dopant could be determined. The two decay constants can be explained by the assumption that W2(hpp)4 molecules, which are involved in the charge transfer, do degrade slower due to the fact that the charge transfer leads to a downshift of the energy levels of the W2(hpp)4 molecule. Apart from the properties of the organic materials, other effects such as the impact of different purification systems on the material purity as well as the dependence of material purity on the OLED lifetime has been investigated. No correlations between the purification grade and the amount of impurities were found. OLEDs which contain N,N\'-di(naphthalen-1-yl)-N,N\'-diphenyl-benzidine (alpha-NPD) purified in a vertically interlaced stainless steel sublimation systems shows slightly higher external quantum efficiencies compared to tube-based vacuum sublimation systems. The devices which contain alpha-NPD purified by a sublimation system have an extended lifetime. Finally, the impact of residual gases during device fabrication on OLED lifetime and electrical characteristics was investigated. It was found that water vapor introduces an additional series resistance to the OLED, while the other gases do not influence the electric characteristics. The presence of nitrogen or oxygen impacts the lifetime of the OLEDs by the same amount. Nitrogen is non-reactive, this leads to the conclusion that the influence of nitrogen and oxygen on the OLED lifetime is of non-chemical nature, such as changes in the morphology of the organic layers. Water vapor introduces an additional, even faster degradation process within the first hours of OLED operation. As major sources of device degradation, the dimerization of 4,7-diphenyl-1,10-phenanthroline (BPhen) as well as the complexation reaction of alpha-NPD with a bis(1-phenylisoquinoline)iridium(III) (Ir(piq)2) fragment was identified.

Le sujet de cette thèse concerne le développement et la caractérisation de résines photosensibles pour le prototypage rapide. L'étude a tout d'abord consisté à optimiser des systèmes photoréticulables commerciaux : systèmes hybrides acrylates/époxydes. La réactivité des différentes formulations préparées ainsi que leurs propriétés thermomécaniques ont pu être évaluées grâce à la spectroscopie infrarouge à transformée de Fourier résolue dans le temps (RT-FTIR) et par analyse mécanique dynamique (DMA). En parallèle, une étude plus fondamentale visant à mieux comprendre et à contrôler la formation de réseaux polymères interpénétrés simultanés méthacrylate/époxyde a été menée. L'influence de paramètres physico-chimiques tels que l'intensité lumineuse, la concentration en photoamorceur sur les propriétés finales du matériau a notamment été abordée. Ensuite, des résines dont la chimie est moins conventionnelle ont été considérées. Comme très peu de ces monomères sont disponibles commercialement, certains d'entre eux ont dû être synthétisés. Certaines formulations ont démontré non seulement une bonne réactivité mais aussi d'intéressantes propriétés thermomécaniques et une limitation du retrait de polymérisation. Finalement, une méthode de mesure du retrait linéaire simple et facile à mettre en œuvre a été mise en place afin de comparer les différents systèmes chimiques proposés au cours de la thèse. L'utilisation de cet outil est très appréciable car il pourrait permettre de choisir le type de formulations induisant le moins de retrait possible lors de la réalisation d'un objet couche par couche. / The aim of this thesis is to develop and characterize UV curable resins for rapid prototyping application. The study started with the optimization of commercially available hybrid acrylate/epoxide systems (IPNs) commonly used in this industrial field. The reactivity of the different tested formulations in conjunction with their thermomechanical properties have been assessed by means of Real time Fourier transform infrared spectroscopy (RT FTIR) and Dynamic mechanical analysis (DMA). In the meantime, a more academic study has been performed on an epoxide/methacrylate mixture in order to get a better understanding and a control of the IPN formation. The influence of the light intensity and the photoinitiator concentration on the final properties has been examined. Then, UV curable resins whose chemistry is less conventional have been considered. Owing to the lack of commercial availability of some monomers, time has been spent to synthesize them. Some formulations display promising features especially in terms of reactivity, thermomechanical properties and linear shrinkage. Finally, a simple method to measure linear shrinkage has been set up to compare the different systems proposed during the thesis and thus evidences the less shrinkable UV curable system.