La complexité et le coût croissant des processus nécessaires pour fabriquer des processeurs de plus en plus puissants de l'industrie microélectronique conduit à des structures de plus en plus petites. La photolithographie, technologie clé pour la nanostructuration, atteint aujourd'hui ses limites en termes de résolution. Des méthodes alternatives doivent donc être trouvées afin de continuer à produire des transistors plus efficaces, tout en gardant les coûts de production à un niveau raisonnable. La combinaison de la photolithographie classique et de l'auto-assemblage de copolymères à blocs (CPB) semble être une alternative prometteuse. Les copolymères à blocs ont la propriété de créer une séparation de phases à l'échelle du nanomètre grâce à l'incompatibilité chimique (décrite par le paramètre d'interaction chi) des blocs. De cette façon, lorsque cette séparation de phase est formée à la surface d’un substrat, des structures telles que des sphères, des cylindres ou des lamelles peuvent être obtenues et utilisées comme masques de gravure pour la nanostructuration. Le CPB le plus utilisé est le Polystyrène-Polyméthacrylate de méthyle (PS-PMMA), qui a été étudié pendant plus de 20 ans. Le PS-PMMA est un CPB de faible chi et ne peut pas atteindre des tailles de structure inférieure à 10nm. Plus l'incompatibilité des blocs (c’est-à-dire le chi) est importante, plus la taille des structures possibles est petite. Cette thèse traite principalement le système Polystyrène-Polydiméthylsiloxane (PS-PDMS), un CPB de haute valeur de chi, et évalue son éventuelle intégration dans l'industrie de la microélectronique. Des procédés ont été développés et optimisés en vue de leur utilisation future dans l'industrie. Un procédé de recuit commun pour les "high-chi" est le recuit sous vapeur de solvant (RVS), où la couche de CPB est exposée aux vapeurs de solvants. Les molécules de solvant gonflent le CPB et augment ainsi la mobilité des chaînes de polymère, permettant l’organisation des structures à grande échelle. Bien que ce procédé soit largement utilisé, il n'a jamais été rapporté sur des lignes de production à grande échelle. Le RVS est un processus très complexe qui est sensible à l'environnement et utilise souvent des solvants toxiques. Au cours de cette thèse, des mécanismes de RVS sont étudiés et des solvants non-toxiques qui sont compatibles avec l'environnement industriel sont proposés comme alternative. Une autre solution pour le recuit de CPBs "high-chi" sans solvant est également proposée. En formulant la solution de CPB avec des molécules de plastifiant, un auto-assemblage rapide avec un simple recuit thermique est possible. La faisabilité de ce processus a été démontrée sur des tranches de silicium de 300mm de diamètre. Le transfert des motifs par gravure est une étape importante et problématique en nanofabrication. Plus les tailles sont réduites, plus le facteur d'aspect est haut et le processus de gravure difficile. Des procédés de gravure par plasma différents, tous généralement utilisés dans les procédés de gravure industrielle, sont étudiés sur le matériau PS-PDMS. Des nanostructures de silicium de 10nm de large et des structures avec un rapport d'aspect de 6:1 ont été gravées avec succès. Enfin, un processus d’inclusion d’oxydes métalliques par simple dépôt par centrifugation a été démontré sur le polymère PS-PMMA. Ce BCP a l'avantage d’être un système bien connu grâce aux nombreux groupes de recherche qui s’y intéresse. Cependant, ses performances en gravure pour le transfert des motifs est peu satisfaisant à cause de la faible sélectivité entre les blocs PS et PMMA. Des procédés de gravure compliqués en plusieurs étapes doivent être effectués afin de transférer les motifs de manière satisfaisante. En introduisant des sels métalliques de manière sélective dans l'un des blocs, le contraste de gravure est considérablement augmenté et le transfert du motif peut être obtenu en une seule étape de gravure plasma. / The increasing cost and complexity of processes needed to keep up with the ever increasing demand for more powerful processors in the IC industry, lead to smaller and smaller feature sizes. Photolithography, once the workhorse for nanostructuration, reaches now its physical limits in terms of resolution. Other, alternative methods have thus to be found in order to continue producing more efficient integrated circuits, while keeping the production costs at a reasonable level. The combination of conventional photolithography and directed self-assembly of block copolymers (BCP) seems to be one promising alternative. Block copolymers have the unique property to phase separate at the nanometer scale driven by the chemical incompatibility (described by the Flory-Huggins interaction parameter chi) of the blocks. This way, when brought onto a substrate, structures like spheres, cylinders or lamellar can be obtained and used as etching masks for nanostructuration. Probably the most used BCP is Polystyrene-b-Polymethylmethacrylate (PS-b-PMMA), which has been studied for over 20 years. PS-b-PMMA is a so called “low-chi” BCP and can reach feature sizes not smaller than 10 nm. The higher the incompatibility of the blocks (i.e. the higher the chi-value), the smaller the obtainable feature size. This thesis deals primarily with “high-chi” Polystyrene-b-Polydimethylsiloxane (PS-b-PDMS) block copolymers and evaluates its possible integration into IC industry. Processes are developed and optimized in view of their future application in industry. A common annealing method for “high-χ” block copolymers is solvent vapor annealing (SVA), where the BCP layer is exposed to solvent vapors. Solvent molecules swell then the BCP layer, increasing the mobility of polymer chains and allowing long range ordering of the features. Although this method is widely used, it has never been reported on large scale production lines, for example on 300 mm wafers. The SVA is a very complex process that is sensitive to the environment and uses often toxic solvents. During this thesis, mechanisms of solvent vapor annealing are studied and safe solvents that are compatible with industrial environment are studied. Furthermore alternative solutions for annealing high-chi BCPs without solvents are proposed. Blending the BCP with plasticizer molecules, for example, leads to rapid self-assembly with thermal annealing and the feasibility of this process was shown on 300 mm wafers.Pattern transfer etching is a problematic step in IC nanostructuring. The smaller the features, the higher the aspect ratio, the more challenging the etching process. Different plasma etching procedures, all typically used in industrial gate etching processes, are studied on PS-b-PDMS. Challenging silicon features of down to 10 nm and aspect ratios of up to 6:1 are obtained.Finally, a simple spin-coating process of metal-oxide inclusion on widespread PS-b-PMMA is introduced in which etch selectivity of the BCP is highly increased. PS-b-PMMA has the advantage of being studied by numerous research groups and the understanding of the BCP is very advanced. However, its etching quality for pattern transfer are very poor as to the poor etch selectivity between PS and PMMA. Complicated multiple-step etching processes, where wet etching and dry etching are alternated have to be performed in order to transfer the patterns satisfactorily. By introducing metal salts selectively in one of the blocks, the etch contrast is considerably enhanced and the pattern transfer can be obtained in one single step of dry etching.

Ultrasound directed self-assembly (DSA) utilizes the acoustic radiation force associated with a standing ultrasound wave field to organize particles dispersed in a fluid medium into specific patterns. The ability to tailor the organization and packing density of spherical particles using ultrasound DSA in a viscous fluid medium is crucial in the context of (additive) manufacturing of engineered materials with tailored properties. However, the fundamental physics of the ultrasound DSA process in a viscous fluid medium, and the relationship between the ultrasound DSA process parameters and the specific patterns of particles that result from it, are not well-understood. Researchers have theoretically described the acoustic radiation force and the acoustic interaction force that act on spherical particles in a standing ultrasound wave field in both inviscid and viscous media. In addition, they have solved the forward and inverse ultrasound DSA problem in an inviscid medium, in which they relate the patterns of particles and the ultrasound DSA operating parameters. However, no theoretical model exists that allows simulating the steady-state and transient local particle packing density in a viscous medium during ultrasound DSA. Thus, in this dissertation, we (i) theoretically derive and experimentally validate a model to determine the steady-state locations where spherical particles assemble during ultrasound DSA as a function of medium viscosity and particle volume fraction. (ii) We also theoretically derive and experimentally validate a model to quantify the steady-state and transient local packing density of spherical particles within the pattern features that result from ultrasound DSA. Using these models, we quantify and predict the locations where spherical particles assemble during ultrasound DSA in a viscous medium, considering the effects of medium viscosity and particle volume fraction. We demonstrate that the deviation between locations where particles assemble in viscous and inviscid media first increases and then decreases with increasing particle volume fraction and medium viscosity, which we explain by means of the sound propagation velocity of the mixture. In addition, we quantify and predict the steady-state and transient local packing density of spherical particles within the pattern features, using ultrasound DSA in combination with vat photopolymerization (VP). We show that the steady-state local particle packing density increases with increasing particle volume fraction and increases with decreasing particle size. We also show that the transient local particle packing density increases with increasing particle volume fraction, decreasing particle size, and decreasing fluid medium viscosity. Increasing particle size and decreasing fluid medium viscosity decreases the time to reach steady-state. Finally, we implement single and multiple scattering in the calculation of the acoustic radiation force for spherical particles in a viscous medium and quantify their relative contributions to the calculation of the acoustic radiation force as a function of ultrasound DSA operating parameters and material properties. We demonstrate that the deviation between considering single and multiple scattering may reach up to 100%, depending on the ultrasound DSA process parameters and material properties. Also, increasing the particle volume fraction increases the need to account for multiple scattering. Quantifying and predicting the local packing density of spherical particles during ultrasound DSA in a viscous medium, as a function of ultrasound DSA process parameters is crucial towards using ultrasound DSA in engineering applications, in particular (additive) manufacturing of engineered polymer matrix composite materials with tailored properties whose properties depend on the spatial organization and packing density of particles in the matrix material. / Doctor of Philosophy / Ultrasound directed self-assembly (DSA) is a technique that uses ultrasound waves to arrange small particles submerged in a fluid into specific patterns. When combined with other manufacturing techniques, ultrasound DSA can be used to fabricate composite materials that derive their properties from the spatial organization of particles in a matrix material. However, ultrasound DSA in viscous fluids is not well-understood. Researchers have studied the forces associated with ultrasound waves that move small spherical particles in an inviscid fluid medium (fluids that experience little to no internal resistance to flow), and they have demonstrated intricate control of the patterns of particles that form using ultrasound DSA. However, that knowledge is not currently available for ultrasound DSA in viscous media. In this dissertation, we develop and evaluate theoretical models to understand ultrasound DSA of small spherical particles in a viscous fluid medium. We simulate where particles organize and how densely they pack together. We also determine the difference of the time-dependent motion of particles in a viscous fluid compared to that in an inviscid fluid medium and relate the difference to the number of particles submerged in the fluid and the viscosity of the fluid. Additionally, we examine the effect of particle size and fluid viscosity on the speed by which the particles reach their final location. We also study how ultrasound waves interact with multiple small particles in a viscous fluid, focusing on the forces that move these particles. We explore two models that account for single and multiple ultrasound wave scattering. Scattering is the process by which ultrasound waves deflect in different directions when they encounter a particle. The results show that the difference between single and multiple scattering models can be significant, depending on the ultrasound DSA process parameters and the properties of the fluid and particles. In general, the importance of accounting for multiple scattering increases with the number of particles submerged in the fluid. Understanding particle packing density when using ultrasound DSA in a viscous fluid is essential in many engineering applications, in particular manufacturing of composite materials that derive their properties from the spatial arrangement of particles in a matrix material.

Block copolymer (BCP) thin film patterns, generated using directed self-assembly (DSA) of diblock copolymers, have shown excellent promise as templates for semiconductor device manufacturing since they have the potential to produce feature pitches and sizes well below 20 nm and 10 nm, respectively, using current 193 nm optical lithography. The goal of this work is to explore block copolymers with sufficient thermodynamics driving force (as described by the Flory Huggins interaction parameter, χ) for phase separation at these smallest lengths scales. Here, poly(styrene)-b-poly(hydroxystyrene) is investigated since the PHOST domain is known to form extensive hydrogen bond networks resulting in increased χ due to this strong enthalpic interaction. In this work, nitroxide mediated polymerization (NMP) techniques were utilized to produce PS-b-PHOST diblock copolymers with a range of molecular weights (5000-30000) with low PDI approaching 1.2. The phase separation of low molecular weight PS-b-PHOST on neutral underlayer substrates via solvent annealing provided thin film vertical lamellae with 13 nm pitch. These results illustrate the improved resolution of PS-b-PHOST compared with the current industry standard of PS-b-PMMA (with 20 nm pitch). The directed self assembly of lamellar PS-b-PHOST patterns with 18 nm pitch via graphoepitaxy is demonstrated. Also, a highly selective atomic layer deposition (ALD) and etch technique was investigated which provided selective block removal of (PS-b-PHOST) block copolymer patterns which initially exhibited no inherent etch contrast. In this process, the PS domain is removed leaving a high fidelity etch relief pattern of the original block copolymer template. Finally, an alternative system is presented, namely Poly(trimethylsilylstyrene)-block-poly(hydroxystyrene) (PTMSS-b-PHOST), which utilizes silicon containing functionality in one of the blocks, providing high etch contrast. PTMSS-b-PHOST patterns were also exposed to oxygen plasma allowing selective block removal of the PS domain without the need for additional ALD processing steps.

Over the past few decades, supramolecular self-assembly has become an alternative synthetic tool for constructing targeted discrete molecular architectures. Among various interactions, metal-ligand coordination has attracted great attention owing to high bond enthalpy (15−50 Kcal/mol) and predictable directionality. The basic principle of metal-ligand directed self-assembly relies on the proper designing of information encoded rigid complementary building units (a transition metal based acceptor and a multidentate organic donor) that self-recognize themselves in a chemically reasonable way (depends on their bite angle and symmetry) during self-assembly process. As far as acceptor units are concerned, Pd(II) and Pt(II) metal-based cis-blocked 90° acceptors have so far been used greatly for the construction of a library of 2D/3D discrete supramolecular architectures due to their rigid square planar geometry and kinetic lability. However, in some cases the efforts to design finite supramolecular architectures using a cis-blocked 90° acceptor in combination with a bulky donor ligand were unsuccessful, which may be due to the steric demands of donor ligand. Moreover, the resulted assemblies from such cis-blocked 90° building unit are mostly non-fluorescent in nature and limit the possibility of using them as chemosensors for various practical applications. Unlike that of rigid square-planar Pt(II) and Pd(II)-metal based building blocks, the use of other transition metal-based building units for the construction of discrete nanoscopic molecular architectures are known to lesser extent, mainly because of their versatile coordination geometries. However, some of the half-sandwiched piano-stool complexes of late transition metals like Ru, Os, Ir and Rh are known to maintain the stable octahedral geometry under various reaction conditions. Moreover, the self-assembly using redox active transition metal-based building units may lead to redox active assemblies. On the other hand, symmetrical rigid donors have been widely used as the favorite choices for the purpose of constructing desired product mainly due to their predictable directionality. Flexible linkers are not predictable in their directionality during self-assembly process and thus results mostly in undesired polymeric products. Furthermore, metal-ligand directed self-assembly provides opportunity to introduce multifunctionality in a single step within/onto the final supramolecular architectures. Among various functional groups, the incorporation of unsaturated ethynyl functionality is expected to enrich the final assemblies to be π-electron-rich and the attachment of ethynyl functionality with heavy transition metal ions are known to be luminescent in nature due to the facile metal to ligand charge transfer (MLCT). Hence, the final supramolecular complexes can be used as potential fluorescence sensors for electron-deficient nitroaromatics, which are the chemical signature of most of the commercially available explosives. The main thrust of the present investigation is focused on the judicious design and syntheses of multifaceted 2D/3D supramolecular architectures of finite shapes, sizes and functionality using Pt(II)/Ru(II) based “shape-selective” organometallic building blocks and investigation of their application as chemosensors. CHAPTER 1 of the thesis presents a general review on the core concepts of self-assembly and supramolecular chemistry. In particular, it underlines the importance of metal-ligand directional bonding approach for designing a vast plethora of discrete 2D/3D supramolecular architectures with tremendous variation in topology. CHAPTER 2 describes the design and syntheses of a series of 2D metallamacrocycles using carbazole-functionalized shape-selective 90° building units. A new Pt2II organometallic 90° acceptor 3,6-bis[trans-Pt(PEt3)2(NO3)(ethynyl)]carbazole (M1) containing ethynyl functionality is synthesized via Sonagashira coupling reaction and characterized. The combination of M1 with three different flexible ditopic donors (L1−L3) afforded [2 + 2] self-assembled molecular squares (1−3), respectively [where L1 = 1,3-bis(4-pyridyl)isophthalamide; L2 = 1,3-bis(3-pyridyl)isophthalamide; L3 = 1,2-bis(4-pyridyl)ethane] (Scheme 1). Scheme 1: Schematic presentation of the formation of a series of [2 + 2] self-assembled molecular squares. An equimolar (1:1) combination of same acceptor M1 with rigid linear ditopic donors (L4-L5) yielded [4 + 4] self-assembled octanuclear molecular squares 4 and 5, respectively [L4 = 4,4’-bipyridine; L5 = trans-1,2-bis(4-pyridyl)ethylene]. Conversely, a similar reaction of M1 with an amide-based unsymmetrical linear flexible ditopic donor L6 resulted in the formation a [2 + 2] self-sorted molecular rhomboid (6a) as a single product [L6 = N-(4-pyridyl)isonicotinamide]. Despite the possibility of several linkage isomeric macrocycles (rhomboids, triangles and squares) due to different connectivity of the ambidentate linker, the formation of a single and symmetrical molecular rhomboid 6a as an exclusive product is an interesting observation. This chapter also presents the synthesis and characterization of a complementary 90° dipyridyl donor 3,6-bis(4-pyridylethynyl)carbazole (L7). Stoichiometric combination of L7 with several PdII/PtII-based 90° acceptors (M2−M4) yielded [2 + 2] self-assembled molecular “bowl” shaped macrocycles (7−9) respectively, in good yields [M2 = cis-(dppf)Pd(CF3SO3)2; M3 = cis-(dppf)Pt(CF3SO3)2; M4 = cis-(tmen)Pd(NO3)2]. All these newly synthesized macrocycles were characterized by various spectroscopic techniques and molecular structures of some of them were confirmed by single crystal X-ray diffraction analysis. In addition to their syntheses and characterization, fluorescence chemosensing ability for various analytes was investigated. Macrocycle 1 is a system composed of amide-based receptor units and carbazole-based fluorophore moieties. The fluorescence study of 1 elicited a dramatic enhancement in the fluorescence intensity upon gradual addition of P2O74- anion in DMF/H2O solvent mixture, whereas similar titration under identical condition with other anions like F-, ClO4-, and H2PO4- did not show such change. Hence, molecular square 1 can be used as selective fluorescence sensor for pyrophosphate (P2O74-) anion. Due to their extended π-conjugation, macrocycles 3-4 were used as fluorescence sensors for electron-deficient nitroaromatics, which are the chemical signatures of many commercially available explosives. The fluorescence study showed a marked quenching of initial fluorescence intensity of the macrocycles(3-4) upon gradual addition of picric acid (PA) and they exhibited large fluorescence quenching responses with high selectivity for nitroaromatics among various other electron deficient aromatic compounds tested. As macrocycle 7 has large concave aromatic surface, it was utilized as a suitable host for large convex guest such as fullerene C60. The fluorescence quenching titration study suggested that macrocycle 7 forms a stable ~1:1 host-guest complex with C60 and the calculated association constant (KSV) is 1.0 × 105 M-1. CHAPTER 3 presents two-component coordination-driven self-assembly of a series of [2 + 2] molecular rectangles and a [2 + 4] self-assembled molecular tetragonal prism. An equimolar combination of pre-designed linear PtII2-acceptors M5−M6 separately with three different “clip” donors (L2, L8−L9) led to the formation of [2 + 2] self-assembled tetranuclear cationic molecular rectangles (10−15), respectively [M5 = 1,4-bis[trans-Pt(PEt3)2(NO3)(ethynyl)] benzene; M6 = 4,4’-bis[trans-Pt(PEt3)2(CF3SO3)(ethynyl)]biphenyl; L8 = 1,3-bis(3-pyridyl)ethynylbenzene; L9 = 1,8-bis(4-pyridyl)ethynylanthracene]. Rectangles 10-15 showed strong fluorescence in solution owing to their extended π-conjugation. Amide-functionalized rectangle 10 was used as a macrocyclic receptor for dicarboxylic acids. Solution state fluorescence study showed that rectangle 10 selectively binds (KSV = 1.4 × 104 M-1) with maleic acid by subsequent enhancement in emission intensity and addition of other analogous aliphatic dicarboxylic acids such as fumaric, succinic, adipic, mesaconic and itaconic acids causes no change in the emission spectra; thereby demonstrated its potential use as macrocyclic receptor in sensor applications. Since rectangle 15 is enriched with π-conjugation, it was examined as a fluorescence sensor for electron-deficient nitroaromatics such as picric acid, which is often considered as a secondary chemical explosive. The fluorescence study of 15 showed a significant quenching of initial emission intensity upon titrating with picric acid (PA) and it exhibited the largest fluorescence quenching response with high selectivity for picric acid. Scheme 2: Schematic representation of formation of [2 + 4] self-assembled of molecular tetragonal prism. This chapter also describes two-component coordination [2 + 4] self-assembly of a pyrene-based PtII8 tetragonal prism (16) as shown in Scheme 2, using a newly designed tetratopic organometallic acceptor (M7; 1,3,6,8-tetrakis[trans-Pt(PEt3)2(NO3)(ethynyl)]pyrene) in combination with an amide-based “clip” donor (L2) and propensity of this prism (16) as a selective fluorescence sensor for nitroaromatic explosives has been examined both in solution as well as in thin-film. CHAPTER 4 reports the synthesis and structural characterization of a series of Ru(II)-based bi-and tetra-nuclear metallamacrocycles and hexanuclear trigonal prismatic cages. In principle, the self-assembly of a “clip” acceptor with an asymmetrical ditopic donor is expected to give two different linkage isomeric (head-to-tail and head-to-head) molecular rectangles because of different bond connectivity of the donor. However, the equimolar combination of half-sandwiched p-cymene binuclear Ru(II)-based “clip” acceptors (M8−M9) and an amide-based ambidentate donor (L6) resulted in the self-sorting of single linkage (head-to-tail) isomeric rectangles 17−18 as only products, respectively [M8 = [Ru2(μ-η4-C2O4)(MeOH)2(η 6-p-cymene)2](CF3SO3)2; M9 = [Ru2(μ- η4-C6H2O4)(MeOH)2(η 6-p-cymene)2](CF3SO3)2]. Molecular structures of these head-to-tail linkage isomeric rectangles were unambiguously proved by single crystal X-ray diffraction analysis. Likewise, the self-assembly of oxalato-bridged Ru(II) acceptor M8 with a rigid dipyridyl “clip” donor L8 yielded a tetranuclear cationic pincer complex 19, while a similar reaction of M8 with an anthracene-functionalized “clip” donor L9 having shorter distance (between their reactive sites) compared to L8 led to the formation of [1 + 1] self-assembled macrocycle 20. This chapter also represents the design and synthesis of two hexanuclear trigonal prismatic cages (21−22) from the self-assembly of a π-electron rich tripyridyl donor (L10; 1,3,5-tris(4-pyridylethynyl)benzene) in combination with binuclear acceptors M8 and M9, respectively (Scheme 3). Formation of these prismatic cages was initially characterized using various spectroscopic techniques and the molecular structure of oxalato-bridged prism 21 was confirmed by single crystal X-ray diffraction analysis. In addition to the structural characterization, the pincer complex 19 and trigonal prismatic cages 21−22 were used as fluorescence sensors for nitroaromatic explosives owing to their large internal porosity and their π-electron rich nature. Scheme 3: Schematic representation of the formation of [3 + 2] self-assembled trigonal prismatic cage. CHAPTER 5 covers the syntheses of a few discrete metallamacrocycles using flexible imidazole/carboxylate based donors instead of much widely employed polypyridyl donors. The metal-ligand directed self-assembly of oxalato-bridged acceptor M8 and an imidazole-based tetratopic donor (L11; 1,2,4,5-tetrakis(imidazol-1-yl)benzene) in methanol afforded [2 + 1] self-assembled tetranuclear macrocycle 23. Conversely, the similar combination of L11 with 2,5-dihydroxy-1,4-benzoquinonato-bridged binuclear complex (M9) in 1:2 molar ratio in methanol resulted in an octanuclear cage 24. Both the complexes (23−24) were isolated as their triflate salts in high yields and were characterized by various spectroscopic methods including single crystal X-ray diffraction analysis. Scheme 4: Schematic representation of formation of an octanuclear incomplete Ru(II) open prism via ruthenium-oxygen coordination driven self-assembly. This chapter also explains the self-sorting of an unusual octanuclear incomplete prism [Ru8(η6-p-cymene)8(tma)2(μ-η4-C2O4)2(OMe)4](CF3SO3)2 (25) via ruthenium-oxygen coordination driven self-assembly of building block M8 and sodium benzene-1,3,5-tricarboxylate (L12) (Scheme 4). Electronic absorption study indicated that prism 25 exhibited a remarkable shape-selective binding affinity for 1,3,5-trihydroxybenzene (phluoroglucinol) via multiple hydrogen bonding interactions and such shape-selective binding was confirmed by single crystal X-ray diffraction analysis. (For figures pl see the abstract file)

L'oxyde de zinc (ZnO) est un matériau semi-conducteur qui présente des caractéristiques très intéressantes telles que : un gap directe à 3.3 eV à température ambiante, une forte énergie excitonique (60 meV à température ambiante) associé à un caractère piézoélectrique. Ces propriétés permettent de considérer le ZnO parmi les nanomatériaux prometteurs, dans une grande variété d'applications : dans le domaine de l'optoélectronique, de l'énergie photovoltaïque ou de l'environnement. Pour que ces dispositifs deviennent exploitables à l'échelle industrielle, certaines conditions doivent être satisfaites comme le contrôle de la taille des nanostructures ainsi que de leur forme, l'impact de la technique de synthèse sur l'environnement, l'économie de l'énergie utilisée dans la production du matériau. C'est dans ce cadre que nous nous sommes intéressés à l'étude de la croissance des micro / nanostructures de ZnO, en particulier à une dimension (1D). Nos échantillons sont obtenus par la synthèse hydrothermale. Cette méthode nous a permis de réaliser des nanostructures de ZnO de très bonnes qualités cristallines sous pression contrôlée (inférieur ou égal à 15 bar) et à basse température (inférieur à 250 °). Ces conditions de préparation ont l'avantage de limiter la consommation en énergie. D'autre part, nous avons utilisé l'eau comme solvant dans la préparation des solutions, ce qui présente un effet positif pour l'environnement (démarche d'éco-conception ou « green chemistry »). Dans la première partie de ce travail, nous avons étudié l'influence d'un ensemble de paramètres expérimentaux tels que : le temps, la quantité de base, la température… sur la croissance de nanorods afin de déterminer les conditions optimales pour l'obtention de nanorods homogènes, plus denses et avec une faible distribution de tailles. Dans la deuxième partie, nous nous sommes intéressés à l'étude de l'influence induite par les cations présents dans les solutions suite à l'hydrolyse des bases sur la morphologie des micro / nanostructures de ZnO. Enfin, les échantillons obtenus ont fait l'objet d'une caractérisation à la fois structurale et morphologique afin d'exploiter au mieux la richesse des géométries et les tailles des micro / nanocristaux élaborés / Zinc oxide (ZnO) is a material that belongs to the family of transparent conducting oxides (TCO) materials. Because of its important physical and chemical properties, ZnO is widely studied since the elaboration to application. It is considered as semiconductor material which has very interesting features such as a direct gap 3.37 eV at room temperature, a strong exciton energy (60 meV at room temperature) assigned to a character piezoelectric. ZnO thin films are elaborated using different techniques including physical and chemical methods. For our part, we are interested in studying the growth of micro / nanostructures of ZnO, especially one-dimensional (1D) using hydrothermal synthesis. This method allowed us to achieve ZnO nanostructures with very good crystalline qualities under controlled pressure (< 15 bar) and low temperature (<250 ° C). These preparation conditions have the advantage to limit the energy consumption. On the other hand, we have used water as solvent in the preparation of solutions which has a positive effect on the environment (eco-design or “green chemistry”). In the first part of this work, we have studied the influence of some experimental parameters such as time, the amount of base, temperature… on the growth of nanorods in order to determine the optimal conditions of the growth of the nanorods forms and their distributions. In the second part, we are interested to study the influence of the cations present in the solution on the morphology of the micro / nanostructures of ZnO. Finally, the obtained samples were characterized by XRD and SEM for the structure and the morphology and by Raman for optical properties. The different analysis of the results obtained from different techniques show a good compromise

Magneticky řízené samo-uspořádávání v polymerních nanokompozitech je studováno v této dizertační práci. Strukturování polymerních nanokompozitů pomocí relativně slabých magnetických polí (B=0-50 mT) bylo prokázáno jako praktická metoda pro kontrolu jejích nano a mikrostruktury. Vliv intenzity magnetického pole, množství nanočástic, viskozity a času uspořádávání na výslednou strukturu byl studován v různých systémech jako fotopolymer, polyuretan nebo koloidně dispergované nanočástice v acetonu s malým množstvím rozpuštěného polymeru. Samo-uspořádané struktury – bez aplikace vnějšího magnetického pole vykazují vícekrokovou agregaci nanočástic do uskupení s komplexním tvarem. Magnetické interakce byly označené jako odpovědné za agregaci nanočástic v samo-uspořádaných systémech pomocí výpočtů energii mezi-částicových interakcí. S rostoucím magnetickým polem, magnetické nanočástice jsou rychle uspořádané do jednorozměrných částicových řetězů s vysokým aspektním poměrem a homogenní orientaci v polymerní matrici. S prodluženým časem uspořádaní, tyto struktury postupně rostou z malých submikrometrových struktur do velkých mikroskopických super struktur. Táto metoda vykazuje velký potenciál pro kontrolovanou přípravu široké škály struktur v polymerních nanokompozitech vhodných pro technologické aplikace a také pro fundamentální studie. Magneticky uspořádané polymerní nanokompozity vykazují značnou směrovou anisotropii tuhosti kompozitu nad jeho skelným přechodem přičemž, pod skelným přechodem systému není pozorován žádný efekt. Podélně orientované struktury vykazují větší příspěvek k tuhosti kompozitů. Efektivnost vyztužení vykazuje teplotně závislý průběh a maximum je pozorováno přibližně 60 °C nad skelným přechodem. Struktura magneticky uspořádaného polymerního nanokompozitu byla popsána vícero-úrovňovým hierarchickým modelem materiálu. Mikromechanika byla využitá k popisu směrově závislého vyztužení polymerních nanokompozitů a k popisu teplotně závislé tuhosti hybridních struktur složených z nanočástic a polymeru. Schopnost nést napětí, deformovat se a nenulová tuhost hybridních struktur je odpovědná za vyztužení polymerních nanokompozitů. Přítomnost polymerních přemostění mezi nanočásticemi, které přenášejí napěti skrze magnetické struktury je označená jako nezbytná pro mechanickou odezvu polymerních nanokompozitů a pro tuhost hybridních struktur.