Ce travail de thèse porte sur la synthèse et la caractérisation d'une nouvelle classe de tensioactif hybride organiques/inorganiques POSS (Polyhedral Oligomeric SilSesquioxane) greffé poly(oxyde d'éthylène), désigné POSS-POE. Ces composés ont été utilisés comme agent tensioactif dans l'élaboration de formulations époxy-amine à base aqueuse. Parmi les différentes voies de synthèse des POSS-POE étudiées, la voie qui consiste à greffer la chaîne POE et les groupements hydrophobe par hydrosilylation de l'octa(diméthylsiloxy)-octasilsesquioxane (Q8M8H) a été privilégiée. En effet cette méthode nous a permis d'élaborer des POSS amphiphiles à balance hydrophile/hydrophobe facilement modulable. Les composés R7Q8M8-POE avec R (alkyle) de C5 à C8 et POE de 350 à 5000 g/mol ont été synthétisés et caractérisés par RMN 1H, 13C et 29Si. Des chaînes alkyle ramifiées ont été également testées comme hydrophobe afin d'évaluer l'influence de la ramification des groupements alkyle sur les propriétés des POSS POE. L'analyse des POSS POE par diffraction de rayons X aux grands angles (WAXD) a permis de mettre en évidence que les chaînes POE cristallisent selon la même structure cristalline que dans l'homopolymère POE. Même si les cages POSS sont exclues des lamelles cristallines, un ordre à courte distance entre les cages POSS avec un certain degré d'interdigitation entre les chaînes alkyle a pu être mis en évidence. Le degré d'organisation des cages POSS dépend de la longueur de la chaîne POE. La stabilité thermique des POSS POE sous air et sous azote a été étudiée par analyse thermogravimétrique (ATG). Sous azote, les cubes R7Q8M8 ont tendance à augmenter la stabilité thermique des chaînes POE de faible masse molaire (350 g/mol) mais ont un effet déstabilisant dans le cas des chaînes POE plus longues (> 350 g/mol). Sous air, les POSS POE les plus stables présentent une chaîne alkyle hydrophobe en C6. La ramification des chaînes alkyle a un effet négatif sur la stabilité thermique. Le comportement associatif des POSS POE dans l'eau a été étudié par viscosimétrie et par mesure de solubilisation de molécule sonde hydrophobe. La formation d'agrégats micellaires à partir d'une concentration comprise entre 10-4 et 4x10-4 mol/L, selon la longueur des chaînes POE et des groupements hydrophobes, a été mise en évidence. Les propriétés émulsifiantes de ces POSS POE vis-à-vis d'un prépolymère DGEBA sont comparables à un tensioactif non ionique conventionnel nonylphénoxylpolyéthoxyéthanol. Un système époxy amine à base aqueuse incorporant ces unités POSS POE a été développé. Les films réticulés obtenus présentent de bonnes propriétés thermiques et une hydrophilie de la surface nettement inférieure en comparaison des films préparés à partir de l'émulsifiant conventionnel.

Typische assoziative Verdicker für wässrige Systeme basieren auf linearen, doppelt hydrophob endmodifizierten Poly(ethylenglykolen) (PEGs). Diese Polymere aggregieren aufgrund ihrer Struktur in wässriger Lösung und bilden ein Netzwerk aus verbrückten Polymer-Mizellen. Dabei kann ein Polymer-Molekül maximal zwei Mizellen miteinander verbinden. Bisher ist unklar, wie die Anzahl der Endgruppen eines verzweigten, mehrfach hydrophob endmodifizierten hydrophilen Polymers die Struktur und Dynamik solcher Netzwerke beeinflusst. Die Synthese verzweigter Polymere auf PEG-Basis erfolgt mittels lebender ionischer Polymerisation und ist experimentell aufwändig. Das Einführen hydrophober Endgruppen erfordert zusätzliche Synthese-Schritte. In dieser Arbeit wurden hydrophile Sternpolymere mit hydrophoben Endgruppen in einem Schritt hergestellt. Dazu wurde die Technik der radikalischen Polymerisation unter Kettenübertragung durch reversible Addition und anschließende Fragmentierung (reversible addition-fragmentation chain transfer, RAFT) genutzt. Die Synthese der Sternpolymere erfolgte von einem multifunktionalen Kern, der die R-Gruppe der RAFT-Kettenüberträger (chain transfer agents, CTAs) bildete. Die dazu benötigten CTAs wurden so konzipiert, dass mit ihrer Hilfe sowohl die Anzahl der Arme des Sternpolymers (von 2 bis 4), als auch die Länge der hydrophoben Endgruppe (C4, C12, C18) variiert werden konnte. Der große Vorteil der RAFT-Polymerisation ist, dass sie viele polare Monomere für die Synthese der hydrophilen Arme des Sternpolymers toleriert. In dieser Arbeit wurden als Modell-Monomere Oligo(ethylenglykol)methylether-acrylat (OEGA) und N,N-Dimethylacrylamid (DMA) eingesetzt. Beide Monomere bilden nicht-ionische hydrophile Polymere. Poly(OEGA) ist ein Kammpolymer, das auf PEG basiert. Poly(DMA) besitzt dagegen eine deutlich kompaktere Struktur. Die erhaltenen amphiphilen Sternpolymere wurden umfassend molekular charakterisiert. Die Molmassen wurden mit verschiedenen GPC-Systemen bestimmt und der Grad der Endgruppenfunktionalisierung wurde mittels UV/Vis- und 1H-NMR-Spektroskopie überprüft. Die Polymerisation von OEGA zeigt mit den CTAs einige Charakteristika der Polymerisation mit reversibler Deaktivierung (RDRP, auch „kontrollierte radikalische Polymerisation“), wird aber durch Kettenübertragung zum Monomer bzw. Polymer gestört. Diese Nebenreaktion ist auf die Struktur des Monomers als Oligoether zurückzuführen. Bei allen untersuchten Polymerisationen von DMA mit den multifunktionalen CTAs steigt die Molmasse linear mit dem Umsatz. Die erhaltenen Polymere zeigen durchweg monomodale und enge Molmassenverteilungen (PDI ≤ 1,2). Die Molmassen lassen sich in einem weiten Bereich von 25 kg/mol bis 150 kg/mol einstellen und die Endgruppen der Polymere bleiben zu 90 % erhalten. Während die Polymerisation von DMA sowohl mit den di- als auch den trifunktionalen CTAs innerhalb von 3 h zu quantitativen Umsätzen verläuft, wird der quantitative Umsatz des Monomers bei der Polymerisation mit tetrafunktionalen CTAs erst nach 4 h erreicht. Diese Verzögerung ist auf eine Retardierung in der Anfangsphase der Polymerisation zurückzuführen, die sich aus der besonderen Struktur der tetrafunktionalen CTAs erklärt. Auf dem System zur Polymerisation von DMA aufbauend ließen sich Gradienten-Block-Copolymere in Eintopfreaktionen herstellen. Dazu wurde nach Erreichen des quantitativen Umsatzes von DMA ein zweites Monomer zur Reaktionsmischung gegeben. Mit Ethylacrylat (EtA) wurden so lineare amphiphile symmetrische Triblock-Copolymere erhalten. Dabei wurde die Länge des hydrophoben Blocks durch unterschiedliche Mengen an EtA variiert. Mit N,N-Diethylacrylamid (DEA) wurden lineare symmetrische Triblock-Copolymere sowie 3-Arm Stern-Diblock-Copolymere hergestellt, die über einen thermisch schaltbaren zweiten Block verfügen. Bei diesen Polymeren lässt sich die Länge des hydrophoben Teils in situ durch Veränderung der Temperatur variieren. Das Verhalten der amphiphilen Sternpolymere in wässriger Lösung und in Mikroemulsion wurde im Rahmen einer Kooperation an der TU Berlin mit Hilfe von Kleinwinkel-Neutronenstreuung (SANS), dynamischer Lichtstreuung (DLS) und Rheologie untersucht. Die Polymere wirken durch Assoziation der hydrophoben Endgruppen als effektive Verdicker sowohl allein in wässriger Lösung als auch in Mikroemulsion. Die Struktur des gebildeten Netzwerks hängt dabei von der Konzentration des Polymers in der Lösung und der Länge der Endgruppe (Hydrophobie) ab. Die dynamischen Eigenschaften der Lösungen werden außerdem durch die Anzahl der Arme der Polymere bestimmt. / Typically, associative thickeners for aqueous system consist of linear, hydrophobically α,ω-end-capped poly(ethylene glycols) (PEGs). Owing to their structure, these polymers aggregate in aqueous solution, forming a network of bridged micelles. Thus, one polymer molecule can link not more than two micelles. Until now it is unclear whether the structure and dynamics of such networks are influenced by the number of end groups of a branched multiply hydrophobically end-capped hydrophilic polymers. Branched PEG-based polymers are synthesized using the laborious and limited techniques of living ionic polymerization. Introducing hydrophobic end groups demands a multiple-step process. This work presents the one-step synthesis of hydrophilic star polymers with hydrophobic end groups, using reversible addition fragmentation chain transfer (RAFT) polymerization. This radical polymerization method is easy to use and tolerates a large number of polar monomers for the synthesis of the hydrophilic arms of the star polymers. The arms of the polymer were grown from a multifunctional core that formed the R-group of the chain transfer agents (CTAs). The CTAs where tailored to be able to vary the number of arms of the star polymers from 2 to 4 and to vary the length (and therefore the hydrophobicity) of the end groups (C4, C12, C18). Two different polar monomers where used as model monomers: Oligo(ethylene glycol)methyl ether acrylate (OEGA) and N,N-Dimethylacrylamide (DMA). Both monomers yield non-ionic hydrophilic polymers. While poly(OEGA) is a comb polymer based on PEG, poly(DMA) exhibits a more compact structure. The amphiphilic star polymers were characterized extensively. The molar masses were determined using GPC in various solvents and the degree of end functionalisation was monitored using 1H NMR and UV/Vis spectroscopy. The polymerization of OEGA shows some of the expected characteristics of reversible deactivation radical polymerization (RDRP). However, chain transfer to monomer and polymer is a prominent side reaction, limiting the use of this monomer for the fabrication of well-defined material. This reaction can be attributed to the structure of the monomer being an oligoether. For all examined polymerizations of DMA with the multifunctional CTAs the molar mass increased linearly with conversion. The molar mass distributions were monomodal and narrow (PDI ≤ 1.2). Expected values were reached for molar masses from 25 to 150 kg/mol and the end group functionality was about 90 % in all cases. While the polymerization of DMA using di- and trifunctional CTAs proceeded to quantitative conversion within 3 h, an initial retardation period of about 60 min was observed for the polymerization using tetrafunctional CTAs. This retardation was attributed to the peculiar molecular structure of these CTAs. Owing to the well-controlled features of the polymerization of DMA using the multifunctional CTAs, this system was used to obtain tapered block copolymers in a one-pot process. These structures were achieved by adding a second monomer to the reaction mixture after the quantitative conversion of DMA. Using ethyl acrylate (EtA), linear amphiphilic symmetrical triblock copolymers were synthesized. The length of the hydrophobic block was tailored by the addition of varying amounts of EtA. With N,N-Diethylacrylamide as a second monomer, linear symmetric triblock copolymers as well as 3-arm star diblock copolymers were obtained that contain a thermosensitve block. Altering the temperature of aqueous solutions of these polymers varies the length of the hydrophobic block in situ. At the TU Berlin, the behavior of the polymers was studied in aqueous solution as well as in microemulsion. The solutions were characterized by small angle neutron scattering (SANS), dynamic light scattering (DLS) and rheology. The end groups of the polymers aggregate, making the polymers efficient thickeners both in aqueous solution and in microemulsion. The structure of the formed network depends on the concentration of the polymer in solution and on the length of the end group. The dynamic properties of the solutions are governed additionally by the number of arms.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Biological degradable polymers on a basis of renewable raw materials, such as polysaccharides, represent promising alternatives to synthetic polymers used as flocculant or stabilizing agents. Polysaccharides derived from potato starch and chitosan have been modified with benzyl- and the first one with additionally cationic hydroxypropyl-trimethylammonium groups of different degrees of substitution (DS). The aim of this work was to characterize the solution properties of these novel amphiphilic polysaccharides concerning the impact of their DS on charge density, particle size, dynamic surface tension and viscosity behaviour. The work is further focused on investigations on flocculation properties of these amphiphilic polyelectrolytes in dispersions of kaolin and silica to identify the interplay between charge density and hydrophobicity. Flocculation efficiency has been evaluated via joint analysis of charge density measurements (using polyelectrolyte titration), turbidity and TOC measurements, as well as dynamic surface tension measurements applying the drop profile analysis. Particle sizes and particle size distributions have been determined by dynamic light scattering and laser diffraction methods. In addition, these amphiphilic starch derivatives have been used to remove substances which impact negatively the paper production process when using recycled paper, so called stickies. Model suspensions have been studied using a multitude of different measurement techniques with the aim to predict a “sticky potential” and to reduce containing dissolved and colloidal substances such as micro stickies. The surface activity and viscometric behaviour have been studied of solely cationic and moderately and highly substituted, amphiphilic polysaccharides in salt-free and 0.05 M NaCl aqueous solution. For the first time dynamic surface tension measurement results have been correlated with particle sizes and apparent charge density. Rheological investigation of large concentration ranges (0.01–20 g/L) was used to discuss Huggins plots and typical polyelectrolyte behaviour for all polysaccharide derivatives could be found. Overlap concentration and, in dilute aqueous solution, intrinsic viscosity could be determined. For polysaccharide solution in dilute regime semi-empirical equations of Rao and Wolf have been applied, making it possible to get insights to polyelectrolyte conformation in dependence on the DS of both substituents. It is shown that for intrinsic viscosity a change of the impact of both substituents takes place when having derivatives with enhanced hydrophobicity. Data evaluation via the ratio of both DS values had been successfully utilized and thus, the applied method has been identified as being a promising tool to compare a multitude of starch derivatives with substituents of different polarity in various degrees of substitution to get tendencies regarding overall hydrophobicity. Moderate hydrophobic substitution was found to lead to a decrease of the efficient flocculant dose and to an increase of the flocculation window width. Amphiphilic starch derivatives with high DS of hydrophobic moieties showing strong hydrophobic association are effective only at significantly higher doses, but in a broader concentration range compared to cationic starch of the same DS. Joint analysis of adsorption isotherms and flocculation test data has revealed, that the surface coverage required to induce phase separation ranges between 10 and 25 % and is minimal for amphiphilic starch derivatives. This gave the evidence of the complex mechanism of flocculation via combination of electrostatic “charge patch” interactions and bridging. Concerning sticky reduction experiments by systematically studying the interactions between the novel amphiphilic starch derivatives and the model suspension it turned out, that dynamic surface tension is a very suitable property to characterize the surface active compounds in the model suspension giving additional information about the sticky potential of waste water, e.g. white water, being a new and sensitive method to describe the parameter “hydrophobicity”. Moderate cationic and hydrophobic starch derivatives have been proved to be the most effective ones for sticky removal.

Les poly(3-hydroxyalcanoate)s ou PHAs sont des biopolyesters linéaires biodégradables et biocompatibles synthétisés par des microorganismes bactériens en tant que réserve de carbone et d'énergie. Ils sont synthétisés par des bactéries à partir de ressources renouvelables et la diversité de leurs structures possibles se traduit par un large éventail de polymères ayant des propriétés mécaniques très différentes. Nous avons tout d'abord testé les capacités de production de PHAs de nouvelles souches bactériennes marines provenant de tapis microbiens de Polynésie française, en utilisant, entre autres, des substrats naturels comme l'huile de coprah, le glucose et l'acide oléique. Nous avons notamment montré que la souche Pseudomonas guezennei est capable de produire des PHAs avec des taux d'insaturation contrôlés et de masse molaire très élevée. Puis, des oligomères de PHAs fonctionnalisés de structures contrôlées portant des fonctions terminales alcynes ou alcènes ont été préparés par transestérification. Ces oligomères ont ensuite été utilisés pour l'élaboration par chimie click de copolymères amphiphiles greffés EPS-g-PHA avec des exopolysaccharides (EPS) bactériens. Enfin la dernière partie de ces travaux a consisté en la réalisation d'un support de croissance pour le développement de cellules souches pour l'ingénierie tissulaire combinant les propriétés mécaniques des PHAs et les propriétés hydrophiles et bioactives des EPS

Self-assembly of polymeric building blocks is a powerful tool for the design of novel materials and structures that combine different properties and may respond to external stimuli. In the past decades, most studies were focused on the self-assembly of amphiphilic diblock copolymers in solution. The dissolution of these block copolymers in a solvent selective for one block results mostly in the formation of micelles. The micellar structure of diblock copolymers is inherently limited to a homogeneous core surrounded by a corona, which keeps the micelle in solution. Thus, for drug-delivery applications, such structures only offer a single domain (the hydrophobic inner core) for drug entrapment. Whereas multicompartment micelles composed of a water-soluble shell and a segregated hydrophobic core are novel, interesting morphologies for applications in a variety of fields including medicine, pharmacy and biotechnology. The separated incompatible compartments of the hydrophobic core could enable the selective entrapment and release of various hydrophobic drugs while the hydrophilic shell would permit the stabilization of these nanostructures in physiological media. However, so far, the preparation and control of stable multicompartment micellar systems are in the first stages and the number of morphological studies concerning such micelles is rather low. Thus considerably little is known about their exact inner structures. In the present study, we concentrate on four different approaches for the preparation of multicompartment micelles by self-assembly in aqueous media. A similarity of all approaches was that hydrocarbon and fluorocarbon blocks were selected for all employed copolymers since such segments tend to be strongly incompatible, and thus favor the segregation into distinct domains. Our studies have shown that the self-assembly of the utilized copolymers in aqueous solution leads in three cases to the formation of multicompartment micelles. As expected the shape and size of the micelles depend on the molecular architecture and to some extent also on the way of preparation. These novel structured colloids may serve as models as well as mimics for biological structures such as globular proteins, and may open interesting opportunities for nanotechnology applications. / Die Selbstorganisation von synthetischen amphiphilen Blockcopolymeren ist ein vielseitiger Prozeß, der die Entwicklung von neuartigen Materialien, die verschiedene Eigenschaften miteinander verbinden und auch auf äußere Reize reagieren können, ermöglicht. In den letzten Jahrzehnten haben sich viele Untersuchungen mit der Selbstorganisation von Diblockcopolymeren in Lösung beschäftigt. So bilden zum Beispiel amphiphile Diblock-Copolymere in Wasser meist Mizellen die einen hydrophoben Kern und eine hydrophile Hülle besitzen. Ihre potentielle Anwendung als Wirkstoffträger ist jedoch begrenzt, da für die Einlagerung nur ein hydrophober Bereich zur Verfügung steht. Multikompartment-Mizellen, bestehend aus einer wasserlöslichen Hülle und einem unterteilten hydrophoben Kern, sind dagegen neuartige und sehr interessante Strukturen für die Nanotechnologie und im speziellen für die Nanobiotechnologie, da sie sich zum Beispiel als Träger für Arznei- und Wirkstoffe eignen. So könnten in die separaten und untereinander nicht mischbaren Kompartimente im Kern der Mizelle verschiedene hydrophobe Wirkstoffe selektiv eingelagert und auch freigesetzt werden, wobei die hydrophile Hülle die Nanostrukturen im physiologischen Medium stabilisiert. Aus diesem Grund wurden in den letzten Jahren verschiedene Strategien für die Herstellung von Multikompartiment-Mizellen vorgeschlagen. Bis jetzt gibt es jedoch nur eine begrenzte Anzahl an Untersuchungen, die sich mit der Morphologie solcher Mizellen befassen und somit ist auch wenig über ihre innere Struktur bekannt. In der vorliegenden Arbeit konzentrieren wir uns auf vier verschiedene Ansätze zur Herstellung von Multikompartiment-Mizellen durch Selbstorganisation in wässriger Lösung. Eine Gemeinsamkeit bei allen Ansätzen ist, das die untersuchten Copolymere einen hydrophoben Kohlenwasserstoff-Block sowie einen Fluorkohlenstoff-Block besitzen. Die Kombination von Kohlenwasserstoff- und Fluorkohlenstoff-Blöcken wurden gewählt, weil solche Segmente in der Regel nicht miteinander kompatibel sind und somit die Aufteilung in separate Domänen begünstigen. Unsere Untersuchungen haben gezeigt, dass die Selbstorganisation der verwendeten Copolymere in wässriger Lösung in drei Fällen zu Multikompartiment-Mizellen führt. Die Form und Größe der Mizellen ist erwartungsgemäß von der Molekülarchitektur und zum Teil auch vom Präparationsweg abhängig. Diese neuartigen, nanostrukturierten Kolloide könnten als Modell und Mimetika für biologische Strukturen wie die von globulären Proteinen fungieren. Sie eröffnen weiterhin interessante Möglichkeiten für Anwendungen in der Nanotechnologie.

La nanocatalyse à base de métaux de transition constitue un domaine prometteur pour lequel l'efficacité accrue, le caractère de chimie verte et le recyclage sont activement recherchés. Dans cet esprit, cette thèse a été dédiée à la synthèse, la caractérisation et les applications catalytiques de nouveaux nanomatériaux à base de métaux de transition. D'une part, en catalyse homogène colloïdale, des nanoparticules de métaux de transition stabilisées par des ligands amphiphiles ont procuré d'excellentes performances catalytiques en terme d'activité, stabilité et recyclabilité pour la réduction du nitro-4-phénol, le couplage de Suzuki-Miyaura, le transfert d'hydrogéné et la cyclo-addition entre un alcyne et un azoture dans l'eau. D'autre part, en catalyse hétérogène, le design, la synthèse et les applications catalytiques de nano-catalyseurs basés sur les supports de type graphène ou architectures moléculaires organiques ont également été conduits. Leurs excellentes propriétés catalytiques ont été démontrées pour la réduction du nitro-4-phénol, le couplage de Sonogashira, la cyclo-addition des alcynes avec les azotures et l'hydrolyse d'ammonia-borane avec génération d'hydrogène dans l'eau dans les conditions ambiantes. / Transition metal nanocatalysis is a promising area, where increased efficiency, greenness and reusability are actively sought. In this spirit, the thesis has been devoted to the synthesis, characterization and catalytic applications of new transition metal nanomaterials. Amphiphilic ligand stabilized transition metal nanoparticles catalysts have provided excellent catalytic performances in terms of activity, stability and recyclability in the 4-nitrophenol reduction, Suzuki-Miyaura coupling, transfer hydrogenation and alkyne-azide cycloaddition reactions with low amounts of metal loadings. Moreover, an efficient amphiphilic "click" CuI catalyst was also designed for part-per-million levels of alkyne-azide cycloaddition reaction in water. The design, synthesis and catalytic application of heterogeneous nanocatalysts based on graphene and metal organic framework supports have also been carried out, and their excellent catalytic properties in 4-nitrophenol reduction, Sonogashira coupling, alkyne-azide cycloaddition and hydrolysis of ammonia-borane for hydrogen generation in water under ambient conditions have been disclosed.

Notre équipe a récemment développé une méthode polyvalente permettant de préparer des dérivés complexes de C60 hexa-adduits fonctionnalisés. Cette méthodologie permet d’obtenir des produits aux caractéristiques originales. Le C60 central agit comme un support central peu réactif, autour duquel des fonctionnalités sont réparties dans un espace octaédrique parfaitement défini. La première partie de ce travail de thèse a consisté à exploiter cette méthodologie pour créer des C60 hexa-adduits polycationiques aux propriétés de transfection remarquables. Dans un second temps, les dendrons polyamines synthétisés ont été mis à profit pour créer des structures supramoléculaires de C60 hexa-adduits, sous forme micellaire. Par la suite, l’étude de ces assemblages a orienté nos investigations vers l’élaboration de dérivés de C60 hexa-adduits mannosylés multivalents résultant d’un assemblage supramoléculaire, dont leurs possibles applications biologiques sont actuellement à l’étude. En parallèle une synthèse covalente a permis d’obtenir un «équivalent dendritique» de C60 hexa-adduit multimannosylé. Partant du constat que notre méthodologie est efficace principalement pour des dérivés de C60 hexa-adduits qui ont une régio-sélectivité particulière, la dernière partie a été consacrée au développement de nouvelles voies de synthèses qui pourront permettre de créer des dérivés de C60 avec un contrôle régio-sélectif original. / Our team has recently built a polyvalent method that gives complex functionalized C60 hexa-adducts. This methodology permits to obtain products with original features. C60 acts as an inert scaffold, around which functionnalities are distributed in a well-defined octahedral space. The first part of this thesis describes exploitation of this methodology to create polycationics C60 hexa-adducts, which have shown remarkable gene delivery capabilities. Next, the synthetized polyamine dendrons were used to build supramolecular structure of C60 hexa-adducts, as micellar forms. The study of these self-assembled structures has guided us to design micelles of mannosylated C60 hexa-adducts, which biological applications are under investigation. In parallel a covalent synthesis has furnished a dendrimers-like multimannosylated C60 hexa-adduct. Based on the observation that our methodology to create C60 hexa-adduct is efficient only for a specific regio-selectivity, the last part of this thesis was devoted to the development of new synthetic routes to obtain C60 derivates with an original regio-selective control.

Orientador: Watson Loh / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-16T00:50:27Z (GMT). No. of bitstreams: 1 Silva_AndreLuisCondeda_M.pdf: 1492752 bytes, checksum: 969a849fc8d776ed3dd74fac01294cde (MD5) Previous issue date: 2009 / Resumo: O surfatante cataniônico dodecilsulfato de dodecildimetil-n-hidroxilamônio foi preparado e caracterizado em relação às suas propriedades físico-químicas. O composto apresentou solubilidade muito baixa em água, porém com capacidade de redução da tensão superficial e interfacial entre água e xileno, em ambos os casos com lenta cinética de saturação das interfaces. A solubilidade em solventes orgânicos foi avaliada e constatamos tendência a maior solubilidade em solventes polares como clorofórmio e etanol, e no solvente aromático xileno. O estudo de comportamento termotrópico indicou a existência de fases líquido-cristalinas entre a fase sólida cristalina e a fase líquida isotrópica. A partir dos resultados deste trabalho avaliamos que as possíveis aplicações para estes surfatante estão relacionadas às situações onde a adsorção e deposição seja requerida, e em especial para a preparação de emulsões de água em óleo, com o atributo de baixa solubilidade em ambas as fases, e a possível vantagem de redução de irritabilidade dérmica para cremes e loções. O desenvolvimento desta aplicação requer avanços nos procedimentos de preparação da emulsão de forma a facilitar a adsorção do composto na interface água/óleo / Abstract: The catanionic surfactant dodecyldimehyl-n-hydroxylamonium dodecylsulphate was prepared and its physical-chemical properties were characterized. The surfactant presented very low water solubility, but with ability to reduce the surface tension and the interfacial tension between water and xylene, in both situations with slow kinetics of interface saturation. The solubility in organic solvents was evaluated and the trend for higher solubility in polar solvents like ethanol and chloroform and in the aromatic solvent xylene was noticed. The evaluation of its termotropic behavior was carried out and indicated the existence of liquid crystalline phases between the solid crystalline phase and the isotropic liquid phase. The results of this study indicate the possible applications in situations where adsorption and deposition are required, and for the preparation of water in oil emulsions, with the special feature of low solubility in both phases, with the advantage of reduced skin irritation for creams and lotions. The development of this application requires advancements in the procedures for emulsion preparation in order to allow the surfactant adsorption at the water/oil interface / Mestrado / Físico-Química / Mestre em Química

Deposition of noble metal and semiconductor nanocrystalline thin films has received much attention. CdS and CdSe are important semiconductors used in optical devices. A wet chemical route which uses the interface of two immiscible liquids to control the growth and deposition of nanocrystalline thin films forms the basis of the current study. In this method, a metal precursor dissolved in toluene or decane is held in contact with a water layer containing a reducing or sulphiding agent. The reaction proceeds at the interface of the liquids and results in deposits adhering to the interfacial region. The products of such reactions typically consist of nanocrystals forming a thin film. Stable sols of Au, Ag were found to metathesize on contact with alkylamine in oil to form monolayer films that spread across large areas at the water/oil interface. The nature and properties of interfacial thin films depend on the alkylamine. Nanocrystalline thin films consisting of CdS adhering to the interface starting with a polydispersed aqueous sol of crystallites and alkylamine were obtained. The optical band gaps of the films formed are dependent on the alkylamine chain length, with the shortest chain yielding the largest gap. A systematic increase in particle diameters following adsorption is responsible for changes in the electronic structure of films. The formation of nanocrystalline films of CdS adhering at the interface using a toluene solution of cadmium diethyldithiocarbamate and aqueous Na2S solution, in the presence of tetraoctylammonium bromide (TOAB) in the aqueous phase, was investigated under various reaction parameters, while CdSe was obtained using Na2SeSO3 solution and the influences of deposition temperature and solution concentration were studied. A ternary water/decane/2-butoxyethanol /salt system was used to grow deposits of CdSe and CdS. Nanostructured thin films were obtained at the upper interface of the ternary system, between the emulsive middle layer and oil rich top phase. The influence of deposition conditions such as precursor concentrations and temperature, as well as the nature of the medium on the properties of the deposits was studied. Deposits grown using the ternary system were compared with those obtained using water/decane and water/toluene systems. Reaction parameters such as temperature, solution concentration and the size of CdS and CdSe were controlled. A thin film of CdS and CdSe nanocrystals was formed at the interface. The grain size was found to be dependent on reaction temperature and solution concentration, with higher temperatures and solution concentration resulting in larger grains. The nature of thin films obtained at the interface of two immiscible liquids and of a water/decane/2-butoxyethanol/salt ternary system were studied using Scanning and Transmission electron microscopy, X-ray diffraction and UV-visible spectroscopy.