The term "Metal Matrix Nano-Composites (MMNCs)" broadly refers to a composite system that is based on metal or alloy substrate, combined with metallic or non-metallic nano-scale reinforcements. The main advantages of MMNCs include excellent mechanical performance, feasible to be used at elevated temperatures, good wear resistance, low creep rate, etc. In the recent past, MMNCs have been extensively studied, especially the method of fabrication as the processing of such composites is quite a challenge. Though a variety of processing methods have been explored and studied over the years, none have emerged as the optimum-processing route. The major issue that needs to be addressed is the tendency of nano-sized particles to cluster and also the challenge as to how to disperse them in the bulk melt. This work explored the feasibility of utilizing Lorentz forces to address both of these critical issues: clustering and dispersion. The work was carried out both theoretically as well as with accompanying validation experiments. The results indicate that Lorentz Forces may be viable and should be considered in the processing of MMNCs.

Nano-scale fluid flow is unlike transport on the macro-scale. Pressure gradients typically dominate effects on a large scale while thermal gradients contribute negligibly to the motion of fluid. The situation entirely reverses on the nano-scale. At a microscopic level, flows induced by thermal gradients are caused by forces that act on atoms or molecules near an interface. These thermo-osmotic forces cannot, at present, be derived analytically or measured experimentally. Clearly, it would be useful to calculate these forces via molecular simulations, but direct approaches fail because in the steady-state, the average force per particle vanishes, as the thermo-osmotic force is balanced by a gradient in shear stress. In our journey to indirectly calculate the osmotic force, we met another unknown in the field of molecular theory at interfaces: the microscopic pressure tensor. The latter is an open problem since the microscopic pressure near an interface is not uniquely defined. Using local thermodynamics theories, we relate the thermo-osmotic force to the gradient of the microscopic pressure tensor. Yet, because the pressure is not uniquely defined, we arrive at multiple answers for the thermo-osmotic force, where at most one can be correct. To resolve the latter puzzle, we develop a direct, non-equilibrium simulation protocol to measure the thermo-osmotic force, whereby a thermal gradient is imposed and the osmotic force is measured by eliminating the shear force. Surprisingly, we find that the osmotic force cannot be derived from the gradient of well-known microscopic pressure expressions. We, therefore, derive a thermodynamic expression that gets close. In this work, we report the first, direct calculation of the thermo-osmotic force while simultaneously showing that standard microscopic pressure expressions fail to predict pressure gradients.

Ces travaux de thèse s’inscrivent dans le contexte technico/économique des nanomatériaux notamment les nanoparticules et les copolymères. Aujourd’hui, une révolution technologique est en cours avec l’introduction de ces matériaux dans des matrices plus ou moins complexes présentes dans notre quotidien (santé, cosmétique, bâtiment, agroalimentaire...). Ces matériaux confèrent à ces produits des propriétés uniques (mécanique, électrique, chimique, thermique, ...). Cette omniprésence associée aux enjeux économiques engendre deux problématiques liées au contrôle des procédés de fabrication et à la métrologie associée. La première est de garantir une traçabilité de ces nanomatériaux afin de prévenir tout risque sanitaire et environnemental et la seconde est d’optimiser le développement des procédés afin de pérenniser des filières économiques rentables. Pour cela, les deux techniques les plus courantes de métrologie utilisées sont : la microscopie électronique à balayage (MEB) et la microscopie à force atomique (AFM).Le premier volet des travaux est consacré au développement d’une méthodologie de fusion de données permettant d’analyser automatiquement les données en provenance de chaque microscope et d’utiliser leurs points forts respectifs afin de réduire les incertitudes de mesure en trois dimensions. Une première partie a été consacrée à la correction d’un défaut majeur d’asservissement de l’AFM qui génère des dérives et/ou sauts dans les signaux. Nous présentons une technique dirigée par les données permettant une correction de ces signaux. La méthode présentée a l’avantage de ne pas faire d’hypothèses sur les objets et leurs positions. Elle peut être utilisée en routine automatique pour l’amélioration du signal avant l’analyse des objets.La deuxième partie est consacrée au développement d’une méthode d’analyse automatique des images de nanoparticules sphériques en provenance d’un AFM ou d’un MEB. Dans le but de développer une traçabilité en 3D, il est nécessaire d’identifier et de mesurer les nanoparticules identiques qui ont été mesurées à la fois sur l’AFM et sur le MEB. Afin d’obtenir deux estimations du diamètre sur la même particule physique, nous avons développé une technique qui permet de mettre en correspondance les particules. Partant des estimations pour les deux types de microscopie, avec des particules présentes dans les deux types d'images ou non, nous présentons une technique qui permet l'agrégation d’estimateurs sur les populations de diamètres afin d'obtenir une valeur plus fiable des propriétés du diamètre des particules.Le second volet de cette thèse est dédié à l’optimisation d’un procédé de fabrication de copolymères à blocs (structures lamellaires) afin d’exploiter toutes les grandeurs caractéristiques utilisées pour la validation du procédé (largeur de ligne, période, rugosité, taux de défauts) notamment à partir d’images MEB afin de les mettre en correspondance avec un ensemble de paramètres de procédé. En effet, lors du développement d’un nouveau procédé, un plan d’expériences est effectué. L’analyse de ce dernier permet d’estimer manuellement une fenêtre de procédé plus ou moins précise (estimation liée à l’expertise de l’ingénieur matériaux). L’étape est réitérée jusqu’à l’obtention des caractéristiques souhaitées. Afin d’accélérer le développement, nous avons étudié une façon de prédire le résultat du procédé de fabrication sur l’espace des paramètres. Pour cela, nous avons étudié différentes techniques de régression que nous présentons afin de proposer une méthodologie automatique d’optimisation des paramètres d’un procédé alimentée par les caractéristiques d’images AFM et/ou MEB.Ces travaux d’agrégations d’estimateurs et d’optimisation de fenêtre de procédés permettent d’envisager le développement d’une standardisation d’analyse automatique de données issues de MEB et d’AFM en vue du développement d’une norme de traçabilité des nanomatériaux. / This thesis is included in the technical and economical context of nanomaterials, more specifically nanoparticles and block copolymer. Today, we observe a technological revolution with the introduction of these materials into matrices more or less complex present in our daily lives (health, cosmetics, buildings, food ...). These materials yield unique properties to these products (mechanical, electrical, chemical, thermal ...). This omnipresence associated with the economic stakes generates two problems related to the process control and associated metrology. The first is to ensure traceability of these nanomaterials in order to prevent any health and environmental risks and the second is to optimize the development of processes in order to sustain profitable economic sectors. For this, the two most common metrology techniques used are: scanning electron microscopy (SEM) and atomic force microscopy (AFM).The first phase of the work is devoted to the development of a data fusion methodology that automatically analyzes data from each microscope and uses their respective strengths to reduce measurement uncertainties in three dimensions. A first part was dedicated to the correction of a major defect of the AFM which generates drifts and / or jumps in the signals. We present a data-driven methodology, fast to implement and which accurately corrects these deviations. The proposed methodology makes no assumption on the object locations and can therefore be used as an efficient preprocessing routine for signal enhancement before object analysis.The second part is dedicated to the development of a method for automatic analysis of spherical nanoparticle images coming from an AFM or a SEM. In order to develop 3D traceability, it is mandatory to identify and measure the identical nanoparticles that have been measured on both AFM and SEM. In order to obtain two estimations of the diameter on the same physical particle, we developed a technique that allows to match the particles. Starting from estimates for both types of microscopy, with particles present in both kinds of images or not, we present a technique that allows the aggregation of estimators on diameter populations in order to obtain a more reliable value of properties of the particle diameter.The second phase of this thesis is dedicated to the optimization of a block copolymer process (lamellar structures) in order to capitalize on all the characteristic quantities used for the validation of the process (line width, period, roughness, defects rate) in particular from SEM images for the purpose of matching them with a set of process parameters.Indeed, during the development of a new process, an experimental plan is carried out. The analysis of the latter makes it possible to manually estimate a more or less precise process window (estimate related to the expertise of the materials engineer). The step is reiterated until the desired characteristics are obtained. In order to accelerate the development, we have studied a way of predicting the result of the process on the parameter space. For this, we studied different regression techniques that we present to propose an automatic methodology for optimizing the parameters of a process powered by AFM and / or SEM image characteristics.This work of estimator aggregation and process window optimization makes it possible to consider the development of a standardization of automatic analysis of SEM and AFM data for the development of a standard for traceability of nanomaterials.

<div> <p>TiB₂particulate reinforced aluminum matrix composites (TiB₂/Al-MMCs) have received extensive attention due to a great potential in a wide variety of applications. Nano-TiB₂/Al-MMCs have also received attention from scholars with the development of nanotechnology in recent years. However, obstacles like agglomeration of nanoparticles in the matrix, and the difficulty of preparation of nanoparticulate reinforced metal matrix composites (PRMMNCs) still need to be resolved. This study summarizes the research progress of Al-matrix composites (Al-MMCs) in recent years and exemplifies the common preparation methods. Experiments were designed to study the common problems in the preparation of composite materials.</p> <p> </p> <p>Two experiments were designed and completed in this study. First, TiB₂/Al-4.5Cu composites were synthesized through a mixed salt reaction method. The distribution of reinforcing particle in the aluminum matrix was observed. The predictive model of particle behavior in Al-4.5wt. %Cu matrix based on thermodynamic laws was re-examined. The experiment results are inconsistent with the prediction from a classic prediction model. Regardless of the rate of solidification and critical velocity (V_C), the most of the particles are rejected by advancing solid-liquid interface. Through review of classic particle pushing theory, this study attempts to derive a new boundary condition used to predict the behavior of reinforcing particles in a metal matrix during solidification based on the diffusion convection equations. </p> <p> </p> <p>Second, nano-TiB₂/Al composites with a variety of volume fractions were synthesized by ultrasound assistance in a stirring method. The research has focused on optimization and improvement of preparation methods. High-energy ball milling (HEBM) and high-intensity ultrasound (HIU) were introduced into the fabrication process. Furthermore, a forging post-treatment process is used to process as-cast samples prepared by the experiment, so that the reinforcing particles in the composite material can be redistributed. The experiment results show that HEBM facilitates the mixing of nano-TiB₂ particles with salts. HIU helps distribute particles evenly throughout the matrix. The Vickers hardness and tensile strength of the composites were tested. The results indicated that the forging treatment has great influence on the mechanical properties of composite materials.</p> </div> <b><br></b>

<div>The atomic force microscope (AFM), traditionally known as a nanoscale instrument for surface topography imaging and compositional contrast, has a unique ability to investigate buried, subsurface objects in non-destructive ways with very low energy. The underlying principle is the detection of interactions between the AFM probe and the sample subsurface in the presence of an external wave or eld. The AFM is a newcomer to the field of subsurface imaging, in comparison to other available highresolution techniques like transmission or scanning electron microscopy. Nevertheless,</div><div>AFM offers signicant advantages for subsurface imaging, such as the operation over a wide range of environments, a broad material compatibility, and the ability to investigate</div><div>local material properties. These make the AFM an essential subsurface characterization tool for materials/devices that cannot be studied otherwise. </div><div><br></div><div><div>This thesis develops a comprehensive qualitative and quantitative framework underpinning the subsurface imaging capability of the AFM. We focus on the detection of either electrostatic force interactions or local mechanical properties, using 2nd-harmonic Kelvin probe force microscopy (KPFM) and contact-resonance AFM (CRAFM),</div><div>respectively. In 2nd-harmonic KPFM we exploit resonance-enhanced detection to boost the subsurface contrast with higher force sensitivity. In CR-AFM we use the dual AC resonance tracking (DART) technique, in which the excitation frequencies are near one of the contact resonance frequencies. Both techniques take advantage of the maximized response of the cantilever at resonance which improves the signal to noise ratio. These enable high-resolution subsurface mapping on a variety of polymer</div><div>composites.</div></div><div><br></div><div><div>A relevant challenge is the ability to reconstruct the properties of the subsurface objects from the experimental observables. We propose a method based on surrogate</div><div>modelling that relies on computer experiments using nite element models. The latter are valuable due to the lack of analytical solutions that satisfy the complexity of the geometry of the probe-sample system and sample heterogeneity. We believe this work is of notable interest because offers one of few approaches for the non-destructive characterization of buried features with sub-micron dimensions.</div></div>

Thin nanoporous films are attractive for many potential uses for example gas separation, catalysis, filtration of viruses, ore flotation, or as low-dielectric-constant materials. Zeolite and mesoporous materials are the two important nanoporous material classes. In this thesis, we synthesized and characterized two different thin nanoporous films; (i) mesostructured films at the mica-solution interface; (ii) mechanical exfoliated zeolites. The mesoporous materials are well-defined pore shoe and size, and exhibit various morphologies, such as thin films, etc. In contrast, zeolites are a kind of perfect crystal and the morphologies are strongly related to their structures and are difficult to control. Therefore, first we synthesis mesostructured films at mica-solution interface in acidic solution. In-situ Atomic Force Microscopy (AFM) has been used to reveal the formation process of organic and inorganic mesophase films at the molecular level. Then, we synthesized two-dimensional zeolite structures via mechanical exfoliation process that does not involve any chemical intervention and can be applicable to a wide variety of structures with different chemical makeup. Three different zeolite structure nanosheets related to the structure code MWW, UTL, and MFI have been prepared. AFM and TEM have been used to characterized the exfoliated single nanosheet. In order to broaden the application of the single zeolite nanosheet, platinum nano-clusters are encapsulated within mechanical exfoliated zeolite MFI nanosheets by ion exchange from aqueous solution of [Pt(NH3)4](NO3)2. High-angle annular dark field scanning transmission electron microscopy has been used to indicate the Pt clusters in the zeolite MFI structures. Because of the property of the mechanically as-synthesised exfoliated MFI nanosheets that is the long hydrocarbon chains are essentially intact on both sides of the inorganic layer, and can prevent thickening of the zeolite MFI nanosheets along b-axis, we use the mechanically exfoliated MFI as seeds for further growth to form large scale MFI membrane with uniform nano-thickness. Encapsulating noble metals within the channels or cavities of zeolites has already drawn numerous attentions because the well-defined zeolite structure is able to constrain the metal nanoparticle (NPs) aggregation size and enhance the diversity and activity for catalysis. We use the organic surfactant (C22-6-6Br2) and [Pt(NH3)4](NO3)2 as the structure and metal precursor to form Pt-containing nanowires; and use F- to inhibit the premature precipitation of Pt precursors. After involving F-, the Pt-containing nanowire structures were generated.

Le séquençage du génome de nombreux organismes, en particulier le génome humain, n'a pas bien élucidé les mécanismes qui relient les génes aux fonctions biologiques et aux divers états pathologiques. Par conséquent, une nouvelle approche en science et en médecine - baptisé analyse protéomique - est émergée pour mieux comprendre la complexité cellulaire, pour la découverte de nouveaux marqueurs des pathologies humaines et pour le développement de nouveaux médicaments. Aujourd'hui, l'analyse protéomique est une discipline scientifique en pleine croissance. La nouvelle tendance à la miniaturisation de l'analyse biologique et des dispositifs associés, constatée depuis environ une décennie, a touché l'analyse protéomique. Cette tendance à la miniaturisation trouve ses justifications dans le gain à attendre en termes de vitesse et de débit d'analyse et en terme d'optimisation des analyses. Un haut débit d'analyse est à espérer du fait de la suppression de manipulation intense pour et entre les différentes étapes et également d'une automatisation des analyses avec l'utilisation d'une interface robotisée qui manipule les systèmes. Par ailleurs, cette miniaturisation s'accompagne d'un gain en sensibilité des analyses. Dans ce contexte général, l'objectif de ce travail de thèse et de développer de nouveaux dispositifs et supports chromatographiques miniatures, basés sur les monolithes à base de monomères méthacrylate pour la préparation des échantillons protéomiques. Cette préparation comporte la digestion, la purification, la séparation et l'enrichissement de certaines espèces, notamment les peptides phosphorylés. / The sequencing of the genome of many organizations, especially the human genome, did not elucidate the mechanisms that Iink genes to biological functions and the various pathological states. Therefore, a new approach to science and medicine-called proteomic analysis - has emerged to better understand the complex cell, for the discovery of new markers of human disease and the development of new drugs. Today, proteomic analysis is a scientific discipline growing. The new trend towards miniaturization of biological analysis and related devices, since nearly a decade, has affect proteomic analysis. This trend towards miniaturization has its justifications in the expected gain in terms of speed and flow analysis and optimization in terms of analysis. A high-speed analysis is to be hoped from the abolition of manipulation and intense for the different stages and also an automated analysis with the use of a robotic interface that handles systems. Moreover, this miniaturization is accompanied by a gain in sensitivity analysis. ln this general context, the objective of this thesis work and develop new devices and materials chromatographic miniatures, based on methacrylate monoliths for the preparation of proteomic samples. This preparation includes digestion, purification, separation and enrichment of certain species, including phosphorylated peptides. This work gives me a chance to participate in the BioChipLab consortium, from the GenHomme program of the Ministry of Economy and Finance assembling teams from Lille and Grenoble. The project is run by the pharmaceutical group Sanofi-Synthélabo

Thesis (M.Sc.Eng.) / This research addressed the design and fabrication of nano-patterned sapphire substrates (NPSS) as well as the growth by molecular-beam epitaxy (MBE) on such substrates of AlGaN and InGaN multiple quantum wells (MQWs). In recent years a number of LED manufacturers are developing nitride LED devices emitting in the visible part of the electromagnetic spectrum on micron-patterned sapphire substrate (MPSS). These devices are reported to have lower threading dislocation densities, resulting in improvement of the LED internal quantum efficiency (IQE). Furthermore, the LED devices fabricated on MPSS were also found to have improved light extraction efficiency (LEE), due to light scattering by the patterned substrate. My research focuses on the development of nano-patterned sapphire substrate aiming to improve the performance of LEDs grown by MBE and emitting at the deep ultraviolet region of the electromagnetic spectrum. In order to optimize the nano-patterning of the sapphire substrates for maximum light-extraction, the Finite-Difference Time-Domain (FDTD) simulation method was employed. The LEE enhancement was calculated as a function of the diameter, height and perion of the pattern. The calculations were performed only at a single wavelength, corresponding to the maximum of the emitted LED spectrum, which was taken to be 280 nm. These calculations have shown that the best sapphire substrate patterning strategy for this wavelength is the cone shape pattern in hexagonal array structure. Based on limited number of calculations I found that the optimum period, diameter and height of this cone shaped pattern are 400nm 375nm and 375nm respectively. Experimentally, nano patterned substrates were fabricated through natural and nano-imprint lithography. In natural lithography the first step for the definition of the nano-pattern consists of coating the sapphire substrate with photoresist (PMMA) followed by depositing a monolayer of polystyrene nanospheres, 400nm in diameter, using the Langmuir–Blodgett method. These spheres assemble on the substrate and form a closed packed hexagonal array pattern. Following this step the size of the spheres was slightly reduced using reactive-ion etching (RIE) in oxygen plasma. This was followed by the deposition a chromium film, lift-off to remove the polystyrene spheres and RIE to remove the PMMA from the footprints of the spheres. The substrate was then coated with a nickel or chromium films followed by another lift-off which defines the final mask for the formation of cone shaped features by RIE in a CHF3 plasma. An alternative method for pattern definition was the nanoimprint lithography; the stamp for this method (2 mm2 in size) was formed on Silicon substrate using e-beam lithography. NPSS with high quality pillar shape was also fabricated by this method, however, this method can produce only small size patterns. AlGaN films and GaN/InGaN MQWs were deposited on the NPSS by MBE, and characterized by Scanning electron microscopy and photoluminescence and cathodoluminescence measurements. The cathodoluminescence and photoluminescence spectra show that films grown on NPSS has much stronger luminescence than the films grown on flat sapphire substrate, consistent with enhanced light extraction efficiency.

Nanomaterials are widely used in many different products, such as electronics, cosmetics, industrial goods, biomedical uses, and other material applications. The heavy emission of nanomaterials into the environment has motived increasing concern regarding the effects on ecosystems, food chains, and, human health. Plants can tolerate a certain amount of natural nanomaterials, but large amounts of ENMs released from a variety of industries could be toxic to plants and possibly threaten the ecosystem. Employing phytoremediation as a contamination treatment method may show promise. However a pre-requisite to successful treatment is a better understanding of the behavior and effects of nanomaterials within plant systems. This study is designed to investigate the uptake, translocation, bioavailability, and toxicity of gold nanorods in maize plants. Maize is an important food and feed crop that can be used to understand the potential hazardous effects of nanoparticle uptake and distribution in the food chain. The findings could be an important contribution to the fields of phytoremediation, agri-nanotechnology, and nanoparticle toxicity on plants. In the first experiment, hydroponically grown maize seedlings were exposed to similar doses of commercial non-coated gold nanorods in three sizes, 10x34 nm, 20x75 nm, and 40x96 nm. The three nanorod species were suspended in solutions at concentrations of 350 mg/l, 5.8 mg/l, and 14 mg/l, respectively. Maize plants were exposed to all three solutions resulting in considerably lower transpiration and wet biomass than control plants. Likewise, dry biomass was reduced, but the effect is less pronounced than that of transpiration and wet biomass. The reduced transpiration and water content, which eventually proved fatal to exposed plants, were most likely a result of toxic effect of gold nanorod, which appeared to physically hinder the root system. TEM images proved that maize plants can uptake gold particles and accumulate them in root and leaf cells. However, the translocation factor of gold nanorods from root to leaf was very low in this experiment. In the second experiment, maize seedlings were exposed to different (lower) concentrations of gold nanorods measured at 4.5x10-3 mg/l, 0.45 mg/l, and 2.25 mg/l for 10 days. Transpiration and biomass measurements demonstrated that the higher concentration of gold nanorods caused lower water uptake and growth, but lower concentrations did not show a significant toxic effect. According to ICP-MS results, root systems of the exposed plants were surrounded by high concentrations of sorbed nanorods, which physically interfered with uptake pathways and, thus, inhibited plant growth and nutritional uptake.

Primarily concerned with manipulation and study of matter at the nanoscale, the concept of nanoscience encompasses ideas such as nanomaterial synthesis, characterization, and applications to modern scientific and societal problems. These problems encompass a broad range of issues such as energy storage and conversion, medical diagnostics and treatment, environmental remediation and detection, carbon economy and as well as many others. Silica nanoparticles of porous morphology have broad application to many of these issues. In particular, the utility of silica nanoparticles is facilitated by their large intrinsic surface area, tunable surface chemistry, and synthetic variability in both their size and morphology. This facilitates applications to these problems. However, extensive characterization and deeper understanding is needed before full implementation in key applications can be realized. The work described in this thesis aims to explore fundamental and applied characterization of silica nanoparticles that might be used in biomedical and environmental applications. Fundamental studies of functionalized nanomaterials using NMR spectroscopy reveal complex, dynamic phenomena related to-and ultimately deriving from-the intrinsic and/or modified surface chemistry. Applied studies of nanomaterial-biological interfaces demonstrate free radical chemistry as dominating the toxic response of the materials when exposed to biological systems of interest. Characterization of protein adsorbed on the interface reinforces the ubiquitous nature of protein adsorption on nanomaterial surface in biological and environmental media. Overall, this work illuminates and highlights complex changes that take place in aqueous solution for silica nanoparticles of varied morphology and surface chemistry.