This work is focused on the study of interaction between hyaluronan and high-biocompatible amphiphilic molecules. Using fluorescent probe method, screening of the interaction of cationic lipid 1,2-dipalmitoyl-3-trimethylammonium-propane (DPTAP), mixture of this cationic lipid with zwitterionic lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphochloline (DPPC), with hyaluronan, both native and hydrophobically modified was carried out. Results showed the self-aggregation of DPPC and DPTAP independently on lipids ratio in the mixture and the interaction of DPTAP and DPPC/DPTAP aggregates with hyaluronan at specific ratio of DPTAP and hyaluronan concentration. Physical properties of formed membranes and the influence of cholesterol were also investigated at different DPPC and DPTAP concentration ratio. Last but not least, the non-ionic surfactant-DPPC systems were studied, namely, the size of the formed aggregates, the thermodynamics of solubilisation and the interaction with native hyaluronan.

This doctoral thesis studies the properties and behaviour of phase-separated hydrogels. These can be prepared by interaction of polyelectrolytes with oppositely charged surfactants. Negatively charged polysaccharide hyaluronan and cationic surfactant carbethopendecinium bromide (Septonex), whose properties, behaviour and utilization are described in the first two chapters of theoretical part, were selected for this role. Hyaluronan is naturally-occuring in living organisms and is known for his specific targeting to the tumour cells. Septonex is used as antiseptic and disinfectant. Experimental part of this work is focused on examination of the structure and behaviour of these types of hydrogels especially from rheological point of view. The crucial part of this study was to establish mechanical properties and their dependence on environment. This led to design further studies. Structural analysis was held using the methods of ATR-FTIR, ionic chromatography and ICP-OES helping to measure the inner content of entry materials in the gels and supernatants respectively. The last chapter deals with antimicrobial activity. The results of this study indicate a potential usage of these substances in the field of medical applications.

Nowadays are foam concentrates used as the primary extinguishing agent for flammable liquid fires (especially hydrocarbons), means of transports fires, the release of chemical substances in environmental accidents, and their importance is still growing with the industrial development. All units of fire protection have foam concentrates in their equipment, so it is important that firefighters to have some necessary knowledge about their characteristics and to be able to use them effectively and safely for the environment. The basic component of foaming concentrates are surfactants. This diploma thesis analyzes foam samples which are commonly used, by methods for analysis of drinking, surface and wastewater and determines cationic, anionic and nonionic surfactants.

The effect of hydrophobically modified hyaluronan on surfactants aggregation has been studied in this master’s thesis. The value of critical micelle concentration of anionic surfactant SDBS (sodium dodecylbenzensulfonate), cationic surfactant CTAB (cetyltrimethylamonnium bromide) and nonionic surfactant Triton X-100 (octylphenol ethoxylate) was determined by fluorescence spectroscopy using pyrene probe. Aggregation behavior of surfactants was performed with addition of hydrophobically modified hyaluronan of two molecular weights (17 kDa, 206 kDa) in aqueous solution. The greatest influence of hydrophobized hyaluronan on aggregation behavior was observed in system with cationic surfactant CTAB. Stability of system containing cationic surfactant and hydrophobically modified hyaluronan was established through zeta potential. Last part of thesis deals with size determination using dynamic light scattering.

Surfactants are synthetically made surface-active agents contained in washing and cleaning products. They decrease the surface tension and remove dirt. Surfactants can be divided into three basic classes: anionic, cationic and non-ionic. Thanks to the massive use they penetrate into waste water and can disturb the environment. This diploma thesis deals with the occurrence of surfactants in water and their determination by separation methods, especially LC / MS.

Thesis The main objective of this thesis is the study of boron cluster compounds in solution, their interaction with polymers and the formation of nanostructures. Most of the work was focused around cobalt bis(dicarbollide) (COSAN) but the incorporation of carborane into polymers was also studied. The idea was to close the knowledge gap around the way COSAN aggregates and continue the line of the laboratory in leading this topic. Therefore, we performed in-depth analysis of isothermal titration calorimetry curves to determine the aggregation number at concentrations around the critical micellar concentration (CMC). Thus, the aggregation number obtained was an improvement over previous data obtained a much higher concentration. The use of acetonitrile as a cosolvent in the micellization process helped formulate a model describing how C-H bonds in the COSAN micelles are directed towards the inside of the micelle. Furthermore, COSAN was used as a model drug for loading nanocarriers composed of hydrophobic core and charged corona. The importance of this work relies on the creation of guidelines for drug loading into similar polymeric vectors in order to determine how the nanocarrier will be affected. With the help of coarse-grained simulations, we determined that changes in the hydrophobicity of the...

Cette thèse vise à contribuer à la caractérisation, à l’aide de modélisation et d’expérience, de la dynamique de bulle en microfluidique. Deux régimes d’écoulements rencontrés en microfluidique sont étudiés, le régime bubbly flow et le régime Taylor flow. En particulier, la première partie de cette thèse traite de la dynamique d’un écoulement de type bubbly flow dans un microcanal rectiligne de section circulaire en présence de surfactants. Le code de calcul numérique JADIM est utilisé. Une méthode numérique permettant, d’une part, de simuler le transport de surfactants le long d’une interface qui bouge et qui se déforme, et d’autre part, de simuler l’effet Marangoni crée par une distribution inhomogène de ces surfactants sur cette interface, est implémentée et validée. Les simulations effectuées avec ce code concernant la dynamique d’un écoulement de type bubbly flow montrent par exemple que, le confinement créé par les parois du microcanal résulte en une distribution des surfactants sur la surface des bulles qui est fondamentalement différente d’une distribution rencontrée dans le cas d’une bulle qui se déplace dans un liquide de dimension infinie. En effet, les surfactants s’accumulent en des locations spécifiques sur la surface des bulles et créent des forces de Marangoni locale, qui influencent drastiquement la dynamique des bulles. Dans certains cas, les surfactants peuvent même engendrer une désintégration de la bulle, un mécanisme qui est rationalisé par un bilan de force à l’arrière de la bulle. La méthode numérique implémentée dans cette thèse est également utilisée pour un problème pratique concernant la production artisanale de Mezcal, une boisson alcoolisée produite au Méxique. La seconde partie de cette thèse traite de la dynamique d’un écoulement de type Taylor flow, à l’aide d’expérience et de modélisation. Une méthode expérimentale permettant de mesurer l’épaisseur du film de lubrification qui se forme entre une bulle de Taylor et les parois du microcanal est développée. Cette méthode requiert uniquement une image « brightfield » de la bulle. En plus de la mesure de l'epaisseur du film de lubrification, la méthode permet aussi de mesurer la profondeur du microcannal. Enfin, l'utilisation de la méthode proposée couplée à la mesure de la vitesse de translation de la bulle permet de déduire la tension de surface de celle-ci. Dans le dernier chapitre de cette thèse, l'influence des effets gravitaires sur la dynamique des écoulements de Taylor est quantifiée. Quoique souvent négligée en microfluidique, il est montré que les effets gravitaires peuvent avoir un impact significatif sur la dynamique des écoulements de Taylor. Ces impacts sont quantifiés à l'aide d'expériences et de modélisations. Ce travail a été réalisé à la Princeton University avec Professeur Howard A. Stone pendant un séjour de 7 mois. / This thesis aims at contributing to the characterization of the dynamics of bubbles in microfluidics through modeling and experiments. Two flow regimes encountered in microfluidics are studied, namely, the bubbly flow regime and the Taylor flow regime (or slug flow). In particular, the first part of this thesis focuses on the dynamics of a bubbly flow inside a horizontal, cylindrical microchannel in the presence of surfactants using numerical simulations. A numerical method allowing to simulate the transport of surfactants along a moving and deforming interface and the Marangoni stresses created by an inhomogeneous distribution of these surfactants on this interface is implemented in the Level set module of the research code. The simulations performed with this code regarding the dynamics of a bubbly flow give insights into the complexity of the coupling of the different phenomena controlling the dynamics of the studied system. Fo example it shows that the confinement imposed by the microchannel walls results in a significantly different distribution of surfactants on the bubble surface, when compared to a bubble rising in a liquid of infinite extent. Indeed, surfactants accumulate on specific locations on the bubble surface, and create local Marangoni stresses, that drastically influence the dynamics of the bubble. In some cases, the presence of surfactants can even cause the bubble to burst, a mechanism that is rationalized through a normal stress balance at the back of the bubble. The numerical method implemented in this thesis is also used for a practical problem, regarding the artisanal production of Mezcal, an alcoholic beverage from Mexico. The second part of the thesis deals with the dynamics of a Taylor flow regime, through experiments and analytical modeling. An experimental technique that allows to measure the thickness of the lubrication film forming between a pancake-like bubble and the microchannel wall is developed. The method requires only a single instantaneous bright-field image of a pancake-like bubble translating inside a microchannel. In addition to measuring the thickness of the lubrication film, the method also allows to measure the depth of a microchannel. Using the proposed method together with the measurment of the bubble velocity allows to infer the surface tension of the interface between the liquid and the gas. In the last chapter of this thesis, the effect of buoyancy on the dynamics of a Taylor flow is quantified. Though often neglected in microfluidics, it is shown that buoyancy effects can have a significant impact on the thickness of the lubrication film and consequently on the dynamics of the Taylor flow. These effects are quantified using experiments and analytical modeling. This work was performed at Princeton University with Professor Howard A. Stone during a seven month stay.

Les polymères en étoile connaissent un intérêt accru en raison de leurs propriétés thermiques et mécaniques inimitables. Partant du constat qu’en parallèle la chimie durable se développe à un rythme sans précédent, nous proposons dans cette thèse de développer une stratégie plus « verte » pour la synthèse de polymères en étoile de type D-sorbitol-poly(ε-caprolactone) (star PCL-OHx). Ces derniers seront synthétisés sans solvant (en masse) ou dans des solvants « propres » (CO2 supercritique) et en présence du catalyseur métallique Sn(Oct)2 (qui a été approuvé par la FDA) ou d’un catalyseur enzymatique (Novozym® 435). L’influence de ces paramètres sur l’architecture des étoiles (nombre de bras, masse molaire des bras…) a été rigoureusement analysée et confirmée par différentes techniques d’analyse (RMN 1H, SEC-MALS, SEC-UC, analyse RMN 31P quantitative via la méthode de phosphitylation). Des polymères linéaires monohydroxy (PCL-OH) et téléchéliques dihydroxy (OH-PCL-OH) ont également été synthétisés en parallèle. Ces différentes PCL ont été utilisées comme macroamorceurs hydrophobes pour la polymérisation du monomère cyclique hydrophile éthyl phosphonate d’éthylène. Une large gamme de copolymères amphiphiles a ainsi pu être développée (i.e. des copolymères diblocs en étoile ou des copolymères diblocs et triblocs linéaires). Le comportement d’auto-assemblage en solution de ces copolymères a été étudié par DLS ainsi que par TEM et cryo-TEM. Nous avons également montré que les copolymères amphiphiles triblocs et en étoile sont capables de diminuer la tension de surface (γ) de l’eau en dessous de 45 mN m-1. Enfin, les étoiles PCL-OHx synthétisées en présence d’enzyme ont été fonctionnalisées par réaction avec l’anhydride maléique. Des polymères en étoile, ioniques, tensio-actifs et directement dispersables dans l’eau ont ainsi pu être obtenus. Dans un second temps, ces mêmes polymères ont été photopolymérisés en présence d’une faible quantité de tri(éthylène glycol) divinyl éther (~ 9% par rapport à la masse totale). Les films afférents à ces copolymères en étoile réticulés sous UV ont été analysés par IRTF, DSC et ATG. / Star polymers have attracted considerable attention because of their unique thermal and mechanical properties. At the same time, as sustainable chemistry field is growing in impact at an unprecedented rate, we propose in this work to implement a greener pathway for the synthesis of star D-sorbitol-poly(ε-caprolactone) (star PCL-OHx) using clean solvents (polymerisation in the bulk or in supercritical CO2) and either FDA-approved Sn(Oct)2 catalyst or enzyme catalyst (Novozym® 435). The influence of these parameters on the star architecture (number of arms, MW of arms etc.) was rigorously analysed and corroborated with various analytical techniques (1H NMR, SEC-MALS, SEC-UC, phosphitylation quantitative 31P NMR approach). Linear monohydroxy PCL-OH and dihydroxy telechelic OH-PCL-OH samples were also prepared. The PCL materials obtained were used as hydrophobic macroinitiators for the polymerisation of cyclic hydrophilic ethylene ethyl phosphonate monomer for the synthesis of a range of different amphiphilic materials (i.e. star diblock, linear diblock and triblock copolymers). Self-assembly behaviour in aqueous solution of these copolymers was investigated by DLS, TEM and cryo-TEM. Triblock and star amphiphilic copolymers were revealed to be able to reduce the surface tension (γ) of water down to 45 mN m-1. Finally, enzyme catalysed star PCL-OHx polymers were functionalised with carboxylic end-groups using maleic anhydride. Water-dispersible surface-active ionic star polymers were then obtained. These maleate-functionalised star polymers were then photopolymerised with a small amount of tri(ethylene glycol) divinyl ether (~9wt% of total composition). The UV-cured crosslinked star PCL films produced were then analysed by FTIR, DSC and TGA.

The first step of the synthesis of the hydrocarbon-based chiral surfactant (2) involved the methylation of (S)-leucinol to give (2S)-N-hexadecyl-N,N-dimethyl-(1-hydroxy-4-methyl-1-pentyl)-2-ammonium bromide (2.92g, 67%). The chiral surfactant was synthesized by reacting (2S)-N,N-dimethyl-2-amino-4-methyl-1-pentanol (1) with bromohexadecane (2.06g, 71%). The functionalized styrene for the polymer supported chiral catalyst (6) was synthesized by reacting (1) with 4-vinylbenzyl chloride. The polymerization was carried out with 10% of the functionalized monomer (5) (1.26g, 70.2%), 5% cross-linking agent divinylbenzene, and 85% of styrene with AIBN as the initiator. The structure of each of the products was confirmed by using FTIR and NMR spectroscopy. The activity of the hydrocarbon surfactant and polymeric catalyst were examined by using them as additives in a standard reduction of 2-pentanone with sodium borohydride to yield (R)- and (S)-2-pentanol (3) (4gm, 25%). The resulting alcohol was then esterified with (2S)-methylbutyric acid with iodine as the catalyst and the ester was characterized.

[pt] Emulsões podem ser formadas durante o processo de exploração dos reservatórios de petróleo. Essas emulsões podem trazer diversos prejuízos, como mudanças nas características dos óleos e problemas no bombeamento. Diante disso, aditivos químicos capazes de promover a desestabilização de emulsões de petróleo são importantes para otimizar o processo produtivo e mitigar os problemas causados. Há diversos estudos dedicados à avaliação de substâncias para atuar como desemulsificantes. Porém, a compreensão de como a estrutura química dos aditivos está correlacionada com as características físico-químicas dos óleos e emulsões ainda é escasso. Esse trabalho tem como objetivo entender como as características dos aditivos estão relacionadas com as particularidades de óleos parafínicos e asfaltênicos. Para isso, três óleos brasileiros foram usados para preparar e caracterizar emulsões água-óleo e avaliar sua estabilidade após o uso de diferentes aditivos. As emulsões preparadas com esses óleos apresentaram grandes diferenças nas propriedades reológicas. Entre elas, a viscosidade e gelificação em um dos óleos parafínicos, o que pode impactar diretamente na eficiência de desemulsificação devido à dificuldade de incorporação dos aditivos no bulk da emulsão. A estabilidade das emulsões foi estudada por testes de envelhecimento em diferentes condições de temperatura sem e com adição de diferentes aditivos: surfactantes, polímeros, ácidos orgânicos e inorgânicos e álcoois. De forma geral, aditivos anfifílicos com grupos aniônicos apresentaram melhor eficiência desemulsificante para todos os óleos. A aromaticidade, a acidez e o volume molecular dos aditivos também foram características importantes para a desemulsificação, porém, dependem da temperatura. Confirmou-se que a escolha de um desemulsificante para emulsões de petróleo depende da composição dos óleos e das características reológicas das emulsões formadas. Para emulsões de óleos parafínicos a temperatura foi determinante na eficiência de desemulsificação, enquanto para o óleo asfaltênico, a acidez influenciou mais. / [en] Emulsions can be formed during the exploration process of oil reservoirs. These emulsions, when unwanted, can bring several losses, such as loss of oil and changes in its characteristics and problems in pumping. Therefore, the development of chemical additives capable of promoting the destabilization of oil emulsions is important to optimize the production process and mitigate the problems caused. In the literature, there are several studies dedicated to the evaluation of substances to act as demulsifiers. However, the understanding of how the chemical structure of additives is correlated with the physicochemical characteristics of oils and emulsions is still scarce. This work aims to understand how the characteristics of the substances are related to the particularities of oils and their emulsions to better understand how demulsification occurs and also to propose additives with greater efficiency for the systems studied. To this end, three Brazilian oils were used to prepare water-oil emulsions and to evaluate the demulsifying capacity of different chemical additives. The stability of the emulsions was studied by aging tests under different temperature conditions without and with the addition of the different additives: surfactants, polymers, organic and inorganic acids and alcohols. The tests were carried out under different conditions to evaluate the effect of temperature mainly due to the high paraffin content in some oils. The characterization of the emulsions (without additives) showed large differences in rheological properties between the systems prepared with oils. These include viscosity, thixotropy and gelation in one of the paraffinic oils, which can directly impact the demulsification efficiency due to the difficulty of incorporating the additives into the emulsion bulk. From the aging tests, it was generally observed that amphiphilic substances with high interfacial activity and with anionic groups showed better demulsifying efficiency for all oils. The aromaticity, acidity and molecular volume of the additives were also important characteristics for demulsification, but they are temperature dependent. Finally, it was concluded that in general, the choice of a demulsifier for petroleum emulsions depends on the composition of the oils and the rheological characteristics of the emulsions formed. For paraffinic oil emulsions, the temperature was decisive for the demulsification efficiency, whereas, for the others, the acidity proved to be more decisive.