Dans ce travail, nous nous sommes concentrés sur la création de nanostructures chirales optiquement actives en fabriquant des nanohélices de silice fluorescente afin d’obtenir des matériaux souple, nanométriques, optiquement actifs pour des applications en tant que matériaux nanophotoniques. Dans cette optique, des nanohélices de silice chirales ont été utilisées pour greffer et organiser des nanocristaux inorganiques fluorescents achiraux tels que des quantums dots, des chromophores, des molécules et des polymères fluorescents selon différentes approches. Ces hélices inorganiques ont été formées par procédé sol-gel en utilisant des auto-assemblages hélicoïdaux organiques de molécules amphiphiles (amphiphile gemini cationique, avec un contre-ion chiral le tartrate) en tant que modèles. Tout d'abord, la surface de la silice hélicoïdale a été fonctionnalisée par l’APTES afin de greffer des quantum dots inorganiques ZnS-AgInS2 possédant divers ligands. Dans la deuxième partie, le polymère de dérivé anthracénique fluorescent a été organisé par dépôt et adsorption à la surface de silice hélicoïdale. Afin d’étudier les propriétés chiroptiques, différentes caractérisations ont été réalisées telle que la spectroscopie du dichroïsme circulaire (CD) et celle de la luminescence circulairement polarisée (CPL).Le premier chapitre présente l’étude bibliographique sur différents systèmes d’auto-assemblage organiques chiraux et leurs propriétés chiroptiques. Les études sur la formation de systèmes auto-assemblés chiraux dans différentes conditions, leur morphologie structurale, les techniques de fabrication et leurs applications sont discutées suivies de l'utilisation de nanocristaux fluorescents, à savoir, les quantums dots (QD) et les polymères fluorescents achiraux sur lesquels les propriétés chiroptiques peuvent être obtenues et leurs applications dans les nanodispositifs optiques, les capteurs et la nano-photonique.Dans la première partie du deuxième chapitre, différentes techniques de caractérisation telles que le microscope électronique en transmission (TEM), le microscope électronique en transmission haute résolution (HRTEM), la microscopie confocale, la spectroscopie UV-Vis, celle de la fluorescence, du dichroïsme circulaire (CD) et de la luminescence circulairement polarisée (CPL) sont décrites. Dans la deuxième partie, la synthèse du gemini 16-2-16 ainsi que son mécanisme d'auto-assemblage, et sa transformation en réplica de silice par l'intermédiaire de la chimie sol-gel sont décrits. Ces nanohélices de silice sont fonctionnalisées par le 3-aminopropyltriéthoxysilane (APTES). Leur analyse est effectuée par analyse thermogravimétrique (TGA) et analyse élémentaire (EA).Dans le troisième chapitre, nous nous sommes concentrés sur la synthèse de QDs inorganiques ((ZnS)x-1(AgInS2)x) avec différentes compositions rapport molaire et leurs caractérisations par TEM, TGA, EA, spectroscopie infrarouge à transformée de Fourier (FTIR), mesures de potentiel zêta, spectroscopie d'absorption et d'émission. Quatre types de ligands ont été utilisés, par échange de ligand, pour recouvrir les QDs : sulfure d'ammonium (AS), acide 3-mercaptopropionique (MPA), l-cystéine (L-Cys) et l'oleylamine (OLA). Ces QDs sont greffés à la surface des hélices de silice modifiée par de l’amine suite à des interactions ioniques. Diverses techniques ont été utilisées pour confirmer leur greffage à la surface des hélices de silice, et les propriétés optiques ont été étudiées par spectroscopie d'absorption et d'émission. Après le greffage, différents résultats ont été observés selon le ligand utilisé : la caractérisation par TEM montre que les QDs sont greffés à la surface des hélices de silice. [...] / In this work, we focused on the creation of optically active chiral nanostructures by fabricating fluorescent silica nanohelices in order to obtain optically active nanoscale soft materials for applications as nanophotonics materials. For this purpose, silica chiral nanohelices were used for grafting and organizing achiral fluorescent inorganic nanocrystals, dyes, molecules, and fluorescent polymers through different approaches. These inorganic helices were formed via sol-gel method using organic helical self–assemblies of surfactant molecules (achiral and cationic gemini surfactant, with chiral counterion, tartrate) as templates. First, the surface of helical silica was functionalized by APTES in order to graft inorganic quantum dots ZnS-AgInS2 with different capping ligands. In the second part, fluorescent anthracene derivative polymer was organized via deposition and absorption on the surface of helical silica. To investigate the chiroptical properties, circular dichroism and circularly polarised luminescence characterization were performed.In the first chapter, the bibliographic study on different chiral organic self-assembling systems and their chiroptical properties are shown. The studies on the formation of chiral self-assembled systems in different conditions, structural morphology, fabrication techniques and their applications are discussed followed by the use of fluorescent nanocrystals, i.e., quantum dots (QDs) and achiral fluorescent polymers on which chiroptical properties can be obtained and their applications in optical nanodevices, sensors, and nano-photonics.In the first part of the second chapter, different characterisation techniques such as transmission electron microscope (TEM) , high resolution transmission electron microscope (HRTEM), and confocal microscopy, UV-Vis spectroscopy and fluorescence spectroscopies, as well as circular dichroism (CD) and circularly polarised luminescence (CPL) spectroscopies are described. In the second part, the synthesis of Gemini 16-2-16 as well as their self-assemblies mechanism, and their transformation to silica replica via sol-gel chemistry are described. These silica nanohelices are functionalized by 3-aminopropyltriethoxysilane (APTES). Their analysis is performed by Thermogravimetric analysis (TGA) and elementary analysis (EA).In the third Chapter, we focused on the synthesis of inorganic ((ZnS)x-1(AgInS2)x) QDs with different compositions molar ratio and its characterizations by TEM, TGA, EA, Fourier-transform infrared spectroscopy (FTIR), zeta potential measurements, absorption, and emission spectroscopy. Four types of ligands were used to cap the QDs via phase ligand exchange as follows: ammonium sulphide (AS), 3-mercaptopropionic acid (MPA), l-cysteine (L-Cys) and the fourth one is oleylamine (OLA). These QDs are grafted on the surface of amine-modified silica helices through ionic interaction. Various techniques were used to show the grafting of QDs on the surface of silica helix, and their optical properties were studied using absorption and emission spectroscopy. After grafting, in each case of ligands, different results were observed as follows: The TEM characterization shows that QDs are grafted on the surface of silica helices. In the case of AS-capped QDs, the helical morphology of silica helices after grafting is destroyed; therefore the further ananlysis was not possible. While, in the cases of QDs with three other ligands MPA, OLA and L-cys, dense and homogeneous grafting of the QDs were observed by TEM and the helical morphology was preserved after their grafting. The HRTEM images were taken on the MPA-QDs@silica helices and energy-dispersive x-ray (EDX) analysis was performed in STEM mode, confirming the QDs elements present on the silica surfaces. [...]

En raison de leurs propriétés physiques uniques, les matériaux chiraux trouvent des applications aussi bien en physique, qu’en chimie ou biologie. Ici, nous nous intéressons à la synthèse de nanoobjets inorganiques chiraux et à leur utilisation en tant que systèmes nano-électromécaniques.Différents auto-assemblages à base de surfactants Gemini et de contre-ions chiraux (nucleotide ou tartrate) formant dans l’eau des hélices micrométriques et nanométriques sont étudiés. Ces auto-assemblages sont ensuite utilisés comme structures directrices pour la formation d’hélices de silice par transcription inorganique. Le contrôle de la réactivité du précurseur inorganique est crucial pour parvenir aux caractéristiques mécaniques souhaitées.Enfin, une minéralisation secondaire des nano-hélices avec du TiO2 et du ZnO a lieu afin de créer des matériaux fonctionnels aux propriétés électroniques ou piézoélectriques. Différentes approches de synthèse et l’optimisation des procédés sont présentées. / Due to their unique physical properties chiral materials are used in a wide range of applications in chemistry, physics and biology. In this work we focus on the fabrication of chiral functional materials for NanoElectroMechanical systems based on the inorganic transcription of self-assembled surfactants.At first we introduce a new Nucleoamphiphile based system that self-assembles into micrometer sized helical fibers in aqueous medium. The effect of a wide range of chemical and physical parameters on the morphology of the aggregates was investigated. Then the synthesis of chiral silica structures based on the organic micro- and nanohelices as templates was studied to achieve the required mechanical properties of the material. Control over the precursor reactivity is crucial for the transcription of the morphology of the template into the silica replica. Secondary mineralization with TiO2 or ZnO was performed to provide the necessary electrical properties and functionality to the chiral material. Different approaches and the optimization parameters are described in detail. Finally the measurement of the mechanical properties of the silica nanotubes and nanohelices by AFM as the first step of the NEMS development will be described.

L'injection de tensioactifs est une méthode très appliquée dans le domaine de la récupération améliorée des hydrocarbures. Cependant, son efficacité repose sur la capacité de ces agents chimiques à mobiliser l'huile résiduelle en diminuant la tension interfaciale entre l'huile et l'eau. Des modèles à l'échelle du réservoir calculent l'efficacité de la récupération d'huile résiduelle par injection de solutions contenant des tensioactifs. Les mécanismes physiques pris en compte dans les modélisations font intervenir la physico-chimie du système roche-fluide et une courbe globale donnant la saturation résiduelle en huile en fonction du nombre capillaire (courbe de désaturation capillaire). Cette donnée est majeure dans le calcul de l'efficacité de récupération d'huile par injection de solutions de tensioactifs. En effet la mobilisation de l'huile résiduelle laissée en place après injection d'eau n'est possible qu'en augmentant considérablement le nombre capillaire. La prédiction de l'efficacité d'un procédé chimique de récupération passe par la compréhension, à l'échelle du pore, du processus de mobilisation des ganglions d'huile suivant la structure poreuse et le nombre capillaire. L'objet de cette thèse est de caractériser la récupération d'huile tertiaire en fonction du nombre capillaire dans diverses roches mouillables à l'eau. Ces courbes permettront de quantifier l'effet de la microstructure, les hétérogénéités du milieu poreux et diverses propriétés pétrophysiques sur la récupération d'huile. Cette thèse permettra aussi de caractériser les différents mécanismes d'action de tensioactifs sur la mobilisation d'huile résiduelle dans le milieu poreux. L'expérimentation par tomographie RX est utilisée. La tomographie RX permettra de caractériser les courbes de désaturation capillaire à l'échelle de Darcy et visualiser localement le déplacement d'huile résiduelle à travers les milieux poreux. Des essais d'écoulement diphasique sous micro-CT permettront d'observer in-situ et d'étudier les interfaces eau/huile et leurs évolutions en 3D au sein du milieu poreux en fonction du nombre capillaire. / Oil recovery by surfactant injection is related to oil-water interfacial tension and rock properties through the capillary number. In the modeling of oil recovery by surfactant injection, fluid flow physical mechanisms are represented through the capillary desaturation curve (CDC). This curve is central in the evaluation of oil recovery efficiency. In order to mobilize residual oil trapped after waterflooding by capillary forces, chemical EOR rely on increasing capillary number to extremely high values. The mechanisms governing oil release can be described at the pore scale where the balance of capillary and viscous forces is achieved. This description will help to predict the efficiency of surfactant based EOR processes by taking into account the porous geometry and topology, the physico-chemical properties of the fluids and the different phase interaction. The objective of this work is to characterize capillary desaturation curves for various strongly water-wet sandstones. These curves will be used to study the relationship between tertiary oil recovery and the pore structure, porous media heterogeneity and petrophysicals properties. The other aim of this work is to map the different mechanisms of oil recovery by surfactant injection. Experiments under X-Ray tomography are proposed. X-Ray tomography will be applied to characterize capillary desaturation curve at Darcy scale and to visualise the two phase flow saturation after injection. Pore scale experiments based on X-Ray micro-tomography imaging are performed to describe the different mechanisms of oil mobilization.

In this thesis, geometry is used as a basis for conducting experiments aimed at growing and arranging inorganic minerals on curved interfaces. Mineralisation is directed using crystalline and liquid-crystalline metallic soaps and surfactant/water systems as templates.¶ A review of the history, syntheses, structure and liquid crystallinity of metallic soaps and other amphiphiles is presented as a foundation to understanding the interfacial architectures in mesostructured template systems in general.¶ In this study, a range of metallic soaps of varying chain length and cation type are synthesised and characterised to find potentially useful templates for mineral growth. These include alkaline-earth, transition metal, heavy metal and lanthanide soaps. These are systematically characterised using a variety of analytical techniques, including chemical analyses, x-ray diffraction (XRD) infrared spectroscopy (IR) and differential scanning calorimetry (DSC). Their molecular and crystal structures are studied using transmission electron microscopy (TEM), cryo-TEM, electron diffraction (ED), electron paramagnetic spin resonance (EPR), absorption spectroscopy (UV-VIS), high resolution laser spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM), electron dispersive x-ray analysis (EDXA), thermal gravimetric analysis (TGA) and magnetic measurements. Models for the molecular and crystal structures of metallic soaps are proposed. The soaps are predominantly lamellar crystalline or liquid crystalline lamellar rotor phases with tilted and/or untilted molecular constituents. These display evidence of varying degrees of headgroup organisation, including superstructuring and polymerisation. A single crystal structure is presented for a complex of pyridine with cobalt soap. Simple models for their structure are discussed in terms of their swelling properties in water and oils. Experiments are also presented to demonstrate the sorbent properties of aluminium soaps on oil spills.¶ The thermotropic liquid crystallinity of alkaline earth, transition metal, heavy metal and lanthanide soaps is investigated in detail. This is done to assess their suitability as templates, and to document their novel thermotropic behaviour, particularly the relatively unknown lanthanide soaps. Liquid crystalline behaviours are studied using high-temperature XRD (HTXRD), hot-stage optical microscopy and DSC. Models for a liquid crystalline phase progression from crystals to anisotropic liquids are discussed in terms of theories of self-assembly and interfacial curvature. The terminology required for this is drawn from various nomenclature systems for amphiphilic crystals and liquid crystals. General agreement with previous studies is reported for known soaps, while liquid crystallinity is demonstrated in the lanthanide and some non-lanthanide soaps for the first time. A general phase progression of crystalline lamellar through liquid crystalline lamellar to non-lamellar liquid crystalline is discussed in terms of models concerned with the molecular and crystal structures of the soaps and their phase transitions via headgroup and chain re-arrangements.¶ Experiments aimed at guiding growth of metal sulfides using metallic soaps as templates are described, and a model for this growth is discussed. Metal sulfides have been successfully grown by reacting crystalline and liquid crystalline transition metal and heavy metal soaps with H2S gas at room temperature and at elevated temperature. These have been characterised using XRD, TEM, ED and IR. Sulfide growth is demonstrated to be restricted and guided by the reacting soap template architecture. Zinc, cadmium, indium and lead soaps formed confined nanoparticles within the matrix of their reacting soap template. In contrast, curved and flat sheet-like structures, some resembling sponges were found in the products of sulfided iron, cobalt, nickel, copper, tin and bismuth soaps. A model to explain this behaviour is developed in terms of the crystal and liquid crystal structures of the soaps and the crystal structures of the metal sulfide particles.¶ Liquid crystalline iron soaps have been subjected to controlled thermal degradation yielding magnetic iron oxide nanoparticles. Some XRD and TEM evidence has been found for formation of magnetic mesostructures in heat-treated iron soaps. Models for the molecular and liquid crystalline structure of iron soaps, their thermotropic phase progression and eventual conversion to these magnetic products are discussed. Systematic syntheses of mesoporous silicates from sheeted clays are discussed.¶The templates that have been used are cationic surfactants and small, organic molecular salts. Experiments are reported where a cooperative self-assembly of surfactant/water/kanemite plus or minus salt and oils yields 'folded sheet materials' (FSM'S). Templating of kanemite has also been achieved using cobalt cage surfactants. A theoretical prediction of the specific surface areas and specific volumes of homologous sets of FSM's gave excellent agreement with measured values. The geometry and topology of the mesostructures are discussed. A theoretical model is also discussed regarding the curvature found in the sheets of natural clays , and results of templating clays and silica using metallic soaps are presented. Experiments and a model for low temperature nucleation and growth of microporous silicalite-1 are described in terms of silica templating by water clathrates.¶ Finally, the problem of finding minimal surface descriptions of crystal networks is addressed. Combinatoric methods are used to disprove the existence of possible embeddings of type I and II clathrate networks in non-self intersecting periodic minimal surfaces. The crystal network of the clathrate silicate, melanophlogite is successfully embedded in the WI-10 self-intersecting surface. Details of a previously unreported, genus-25 periodic surface with symmetry Im3m are discussed.

Approximately 75 percent (300 000 km) of the total Swedish road network and 20 percent(20 000 km) of the national road network consists of gravel roads. One of the most significantproblems associated with gravel roads is traffic-generated dust emission, which contributes tothe deterioration of the road surface and acts as a major source of particulate matter releasedinto the atmosphere, thereby involving public economics, road safety, human health, andenvironmental quality. In order to bind the fine granular material, which is prone to rise into theair, dust suppressants are applied on roads on a yearly basis. Methods for evaluating the efficiency of dust suppressants will facilitate in the selection of themost appropriate product and its optimal application rate. For example, methods forsupervision of residual dust suppressant concentration are valuable tools for estimatinglongevity and optimal application rates, and, consequently, effectiveness of different products. Application of the proper dust suppressant to a gravel road ensures road safety and ridingcomfort as well as creating a cleaner and healthier environment for residents in buildingsadjacent to the road. It also reduces the need and cost for vehicle repair, road maintenanceactivities, and aggregate supplementation. Both field-based and laboratory research were performed to evaluate the efficiency of varioussuppressants and the influence such factors as product concentration, leaching, and fine materialcontent have on the efficiency of different products. Within the field-based research, a newlydeveloped mobile methodology was used to measure dust emission on numerous test sectionstreated with various dust suppressants. In general, all dust suppressants tested, except apolysaccharide (sugar) and products, which form a brittle surface crust, i.e. lignosulphonate andbitumen emulsion, showed acceptable dust reduction. Test sections treated with a magnesium- or calcium chloride solution were the most effectivelydust suppressed. The application of solutions instead of a solid salts achieves a more uniformproduct distribution and, therefore, probably a more efficient performance. By applying acalcium- or magnesium chloride solution instead of traditionally used solids, the cost for annualdust control, as well as the environmental impact from the release of these chemicals in theenvironment, can be reduced by 50 percent. A significant problem when using dust suppressants is their tendency to leach during rainfalldue to their soluble properties. Residual chloride could be detected in the gravel wearing courseover a longer period of time than lignosulphonate and, therefore, showed more effective longtermperformance. Optimal percentages of fine material for minimal lignosulphonate andchloride leaching were found to be 15 percent by weight and 10-16 percent by weight,respectively. Ions of calcium chloride seemed to initiate flocculation of clay particles, therebypreventing them from leaching. Still, the fine material in gravel wearing courses has to be replenished regularly as indicated by studies of the longevity of fine material. Loss up to80 percent was found after two years. Toxicity tests show that dust suppressant application for dust control purposes, at traditionallyused application rates, does not constitute a threat to sensitive aquatic life. Tests on subsoilwater samples indicated elevated chloride levels, which possibly could cause corrosion to pipes,but not high enough to flavour drinking water. / QC20100616

In multi-level Co/low-k based interconnect systems of ultralarge-scale integrated electronic devices the removal of plasma etch residues by common plasma cleaning processes has been shown to alter material properties like k-value and leakage current of the low-k dielectric. Besides the development of less damaging plasma processes their substitution by wet cleaning steps is in the focus of research and development. With further decreasing feature dimensions the development of wet cleaning processes has to include wetting issues like the non-wetting of small features due to the surface energy of the liquid or pattern collapse effects of low-k dielectric trenches due to high capillary forces This work at first focuses on the determination of the surface energetic character of common cleaning solutions for PERR and differently etched or ashed low-k dielectric surfaces by contact angle analysis, to outline which combinations of solid and liquid will be critical regarding their wetting behavior. Besides the determination of the wetting behavior the contact angle analysis turned out to be a fast and sensible analytic tool to understand the surface modifications introduced by different plasma processes and can help to understand the mechanisms of plasma damage of low-k dielectric surfaces. The analysis showed that especially polymerizing plasma etch processes produce a low-energetic low-k dielectric surface with a negligible polar energy contributions, which inhibits their wetting by high energetic water based cleaning solutions, which actually are favored by semiconductor manufacturers. The strategy to overcome these wetting issues followed in the present work is the reduction of the surface energy of the cleaning liquids by the application of surfactants. Several types of surfactants have been applied to the cleaning liquids and the compatibility of the surfactant solutions to BEOL materials like low-k dielectrics, copper and diffusion barriers as well as their dynamic behavior has been studied. The analysis showed that choosing the appropriate rinsing solution after the cleaning process is essential to ensure its compatibility to porous low-k dielectrics. Optical, electrical and structural data indicated that DIW rinse in most of the cases was not able to remove residual surfactant species within the material, while for an IPA rinse most of the residual surfactants have been removed. Considering the data received for compatibility to low-k materials, copper and barriers, the dynamic behavior of the surfactant solutions as well as influences of increased bath temperature and long term stability a general advice about surfactant selection and processing of surfactant aided solutions within BEOL is given. / In mehrlagigen Kupfer/low-k basierten Metallisierungssystemen hochintegrierter elektronischer Bauelemente kann die Entfernung von Residuen nach der Plasmastrukturierung des Dielektrikums mittels herkömmlicher Plasmareinigungsprozesse zur Schädigung der Isolatorschicht und damit zum Ansteigen der relativen Dielektrizitätszahl sowie der Leckströme führen. Neben der Entwicklung schädigungsarmer Plasmaprozesse stellt der Ersatz dieser Prozesse durch Nassreinigungsschritte zur Ätzresiduenentfernung eine vielversprechende Alternative dar. Mit stetig abnehmenden Strukturabmaßen ist bei der Entwicklung dieser Nassreinigungsprozesse neben der Materialkompatibilität auch das Benetzungsverhalten der Reinigungsflüssigkeit von entscheidender Bedeutung, da die Oberflächenenergie der Reinigungslösung das Eindringen dieser in kleinste Strukturen verhindern und es durch hohe Kapillarkräfte zum Kollaps von Grabenstrukturen im Dielektrikum kommen kann. In der vorliegenden Arbeit wurde zunächst mittels Kontaktwinkelanalyse die Oberflächenenergie verschieden prozessierter low-k Dielektrikaschichten sowie herkömmlicher Lösungen zur Entfernung von Ätzresiduen untersucht, um hinsichtlich ihres Benetzungsverhaltens besonders kritische Materialkombinationen aufzuzeigen. Neben der Bestimmung des Benetzungsverhaltens hat sich die Kontaktwinkelanalyse zur Oberflächenenergieberechnung als schnelle und empfindliche Methode zur Analyse der Auswirkung von Plasmaprozessen auf die Oberfläche von low-k Dielektrika erwiesen. Die Untersuchungen haben gezeigt, dass besonders polymerisierende Plasmaprozesse eine niederenergetische Oberfläche erzeugen, welche von den derzeit in der Halbleiterfertigung bevorzugten hochenergetischen wasserbasierten Reinigungslösungen nur schlecht benetzt wird. Um diesem Effekt entgegenzuwirken wurde in der vorliegenden Arbeit die Senkung der Oberflächenenergie der Reinigungslösungen durch Zugabe von Tensiden untersucht. Es wurden mehrere Tenside unterschiedlichen Typs den Reinigungsflüssigkeiten zugemischt und die Kompatibilität dieser Lösungen mit low-k Dielektrika, Kupferschichten und Diffusionsbarrieren untersucht sowie ihr dynamisches Verhalten analysiert. Dabei hat sich gezeigt, dass die Auswahl der geeigneten Spüllösung nach dem eigentlichen Reinigungsprozess von entscheidender Bedeutung ist. Optische, elektrische sowie strukturelle Daten deuten darauf hin, dass bei Verwendung einer Spülung mit deionisiertem Wasser in den meisten Fällen Tensidrückstände im porösen Dielektrikum verbleiben. Eine Spülung mit Isopropanol war hingegen in der Lage, einen Großteil dieser Tensidrückstände zu entfernen. Unter Einbeziehung der Daten zur Materialkompatibilität und dem dynamischen Verhalten der Tensidlösungen bei Raumtemperatur und erhöhter Badtemperatur sowie ihrer Langzeitstabilität konnte schließlich eine Prozessempfehlung für die Verwendung der benetzungsoptimierten Reinigungslösungen in der BEOL-Prozessierung gefunden werden.

Im Rahmen der vorliegenden Arbeit wurden die Wechselwirkungen im System Bakterium –Tensid – Schadstoff mittels kalorimetrischer Untersuchungen (ITC, DSC) sowie mit XPS-Analysen und durch Zeta-Potential-Messungen an Bakterienoberflächen charakterisiert. Für die Untersuchungen wurden zwei Gram-positive Rhodococcus-Stämme und ein Gram-negativer Pseudomonas putida-Stamm verwendet. Als Biotenside wurden das Rhamnolipid JBR 425 und der von Rhodococcus erythropolis B7g produzierte Trehalosetetraester (THL-4) ausgewählt. Das synthetische Tensid SDS diente als Referenzsubstanz. Aus den kalorimetrischen Experimenten konnte eine starke Wechselwirkung zwischen den Tensiden und den aktiven Bakterienkulturen abgeleitet werden. THL-4 führte beim Wachstum der Rhodococcen auf n-Hexadecan zur Verkürzung der lag-Phase. SDS wies hingegen eine toxische Wirkung für die Bakterienstämme auf. Thermodynamische Betrachtungen ergaben, dass Wechselwirkungen des SDS mit den Bakterienzellen gegenüber der Mizellbildung bevorzugt werden.

Cette thèse est scindée en deux parties. Dans un premier temps, nous présentons deux schémas volumes finis pour la discrétisation des problèmes de diffusion-convection-réaction sur les surfaces mouvantes. Le premier schéma présente une extension du schéma volumes finis avec flux à deux points sur les surfaces mouvantes. Le deuxième développe une méthode de type O-méthode. Cette dernière consiste à construire à partir des inconnus au centre des mailles, des solutions linéaires autour des nœuds de maillage qui intègrent la continuité des flux aux interfaces de mailles. La méthode permet aussi la construction des décentrages amont d'ordre 2 et ainsi, offre au procédé l'ordre 2 de convergence sur tout maillage non dégénéré. Ensuite, nous modélisons l'écoulement du couplage filme mince-surfactant (surface active agent) sur les surfaces mouvantes et simulons à l'aide des schémas volumes finis précédemment définis. Ici, l'utilisation du calcul tensoriel et de la méthode d'approximation par la lubrification permettent de réduire les équations de Navier-Stokes caractérisant le mouvement du filme mince en dimension 3 en un système d'équations définies sur la surface courbe mouvante dont l'inconnu est la hauteur du fluide. Le surfactant supposé insoluble est modélisé par une équation de diffusion convection à la l'interface fluid-air. Nous simulons l'ensemble en utilisant une méthode dite de capture d'interface (Interface tracking method) dérivée des volumes finis définis plus haut. Plusieurs exemples illustrent à suffisance l'efficacité et la précision des différentes méthodes.

This thesis focuses on the synthesis and characterisation of organoclays. X-ray diffraction has been used to study the changes in the basal spacings of montmorillonite clay and surfactant-intercalated organoclays. Variation in the d-spacing was found to be a step function of the surfactant concentration. Three different molecular environments for surfactant octadecyltrimethylammonium bromide (ODTMA) within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. High-resolution thermogravimetric analysis (HRTG) shows that the thermal decomposition of montmorillonite modified with ODTMA takes place in four steps attributing to dehydration of adsorbed water, dehydration of water hydrating metal cations, loss of surfactant and the loss of OH units respectively. In addition, it has shown that the decomposition procedure of DODMA and TOMA modified clays are very different from that of ODTMA modified ones. The surfactant decomposition takes place in several steps in the DODMA and TOMA modified clays while for ODTMA modified clays, it shows only one step for the decomposition of surfactant. Also TG was proved to be a useful tool to estimate the amount of surfactant within the organoclays. A model is proposed in which, up to 0.4 CEC, a surfactant monolayer is formed between the montmorillonite clay layers; up to 0.8 CEC, a lateral-bilayer arrangement is formed; and above 1.5 CEC, a pseudotrimolecular layer is formed, with excess surfactant adsorbed on the clay surface. While for dimethyldioctadecylammonium bromide (DODMA) and trioctadecylmethylammonium bromide (TOMA) modified clays, since the larger sizes of the surfactants, some layers of montmorillonite are kept unaltered because of steric effects. The configurations of surfactant within these organoclays usually take paraffin type layers. Thermal analysis also provides an indication of the thermal stability of the organoclay as shown by different starting decomposition temperatures. FTIR was used as a guide to determine the phase state of the organoclay interlayers as determined from the CH asymmetric stretching vibration of the surfactants to provide more information on surfactant configurations. It was used to study the changes in the spectra of the surfactant ODTMA upon intercalation into a sodium montmorillonite. Surfaces of montmorillonites were modified using ultrasonic and hydrothermal methods through the intercalation and adsorption of the cationic surfactant ODTMA. Changes in the surfaces and structure were characterized using electron microscopy. The ultrasonic preparation method results in a higher surfactant concentration within the montmorillonite interlayer when compared with that from the hydrothermal method. Both XRD patterns and TEM images demonstrate that SWy-2-Namontmorillonite contains superlayers. TEM images of organoclays prepared at high surfactant concentrations show alternate basal spacings between neighboring layers. SEM images show that modification with surfactant will reduce the clay particle aggregation. Organoclays prepared at low surfactant concentration display curved flakes, whereas they become flat with increasing intercalated surfactant. Fundamentally this thesis has increased the knowledge base of the structural and morphological properties of organo-montmorillonite clays. The configurations of surfactant in the organoclays have been further investigated and three different molecular environments for surfactant ODTMA within the surface-modified montmorillonite are proposed upon the basis of their different decomposition temperatures. Changes in the spectra of the surfactant upon intercalation into clay have been investigated in details. Novel surfactant-modified montmorillonite results in the formation of new nanophases with the potential for the removal of organic contaminants from aqueous media and for the removal of hydrocarbon spills on roads.

This thesis describes the synthesis and characterisation of titania photocatalysts for incorporation into a polyethylene film. Monodisperse, anatase-phase titania nanoparticles are prepared and the synthesis conditions necessary for attraction to a laponite clay support are determined. Methods of preventing agglomeration of the laponite system such as the use of a polyethylene oxide surfactant or chemical modification of the laponite plate edges with a dimethyloctyl methoxysilane are also explored. Finally, photocatalytic studies on the laponite-supported titania nanoparticles are performed, and the compatibility and photoactivity of these materials in the polyethylene film are examined.