Ionic polymer transducers (IPT) are a class of electroactive polymer devices that exhibit electromechanical coupling through charge transport in ionomeric membranes that contain a charge mobilizing diluent and are interfaced with conducting electrodes. Applications of these active materials have been broadly developed in the field of actuators and sensors. Advances in fundamental understanding of IPT performance mechanisms and tuning of the device components has primarily focused on transducers constructed with the commercial ionomer Nafion® due to its overall stability, high ionic conductivity, and availability. The much smaller number of studies conducted with non-perfluorosulfonated ionomers concentrated on changes in chemical composition to address processability, price, ionic conductivity, and hydrated modulus of the final IPT. Also, nearly all ionic polymer transducers operated with water as the diluent until the recent successful development of IPTs with ionic liquids. The objective of this research is to increase the understanding of electromechanical transduction in ionic polymer transducers through the synthesis and characterization of novel branched ionomers. Controlled branching is achieved in sulfonated polysulfones (sBPS) through employment of an oligomeric A₂ + B₃ step-growth polymerization. Structure – property relationships are established for a series of linear and branched sulfonated polysulfones to resolve the effects of polymer topology and charge content on ionomer properties such as hydrated modulus and ionic conductivity. Furthermore, the variation of these parameters is investigated in the presence of ionic liquids as a function of ionic liquid uptake using two methods for introduction of the diluent. One of those methods, based on casting of IPT components in the presence of the ionic liquid, was applied to the Direct Application Process to produce a controlled set of IPT electrodes and transducers to investigate percolation effects of RuO₂ on the device's electrical properties and actuation characteristics. Equivalent circuit modeling of the component and transducer electrical impedance accurately modeled variations in contributing processes and material interfaces to estimate the evolution of effective capacitance based on the electrode composition. Combination of optimized electrode composition, ionic liquid uptake, and the series of linear and branched sulfonated polysulfones allowed for fabrication of a tailored set of novel ionic polymer transducers. Effects of the fabrication process on the ionic conductivity of the membranes and transducers are evaluated using electrical impedance spectroscopy, which also allowed for equivalent circuit modeling to calculate effective capacitance for the series of IPTs that varied in composition, topology, and uptake for both types of fabrication processes. The transducers described in this dissertation are the first IPTs to be designed and actuated with novel ionomers, specifically linear and branched sulfonated polysulfones, in the presence of ionic liquids. Use of sulfonated polysulfones allowed for realization of transducers with high uptakes of the ionic liquid diluent that retained significant hydrated modulus on the order of 2 GPa. Characterization of electromechanical transduction for the series of sBPS – IPTs was demonstrated in cantilever bending through frequency response analysis and step responses in the time domain to low input voltages. Both the ion content and polymer topology of the sBPS ionomeric matrix demonstrated a significant effect on the final actuation performance in relation to variations in charge transport. Also, IPTs constructed with a co-diluent swelling method which emphasized the formation and stability of the ionomer's charge transport pathway demonstrated the greatest actuation responses, up to a peak-to-peak strain of ~0.45 % and strain rates on the order of 0.1 % / s while producing significant blocked force (180 N/Vm). Combination of these actuation performance metrics resulted in maximum energy densities of 1150 mJ/kg and 2.23 mJ/mm³ for the corresponding IPT. / Ph. D.

The formation of lipid bilayer membranes between droplets of ionic liquid is presented as a means of forming functional bimolecular networks for use in sensor applications. Ionic liquids are salts that have a number of useful properties, such as low melting points making them liquid at room temperature and exceedingly low vapor pressure. Ionic liquids have seen recent popularity as environmentally friendly industrial solvent alternatives. Our research demonstrates that it is possible to consistently form lipid bilayers between droplets of ionic liquid solutions. Analysis shows that the ionic liquids have negligible effects on the physical stability and electrical properties of the bilayer. It is also shown that the magnitude of the conductance levels of Alamethicin peptide are altered by some ionic liquids. / Master of Science

Cette thèse traite de la modification de surface des nanotubes de carbone avec des polymères Le chapitre I présente l'état de l'art des matériaux hybrides associant des liquides ioniques avec des nanotubes de carbone (NTC) ou du graphenes. Le chapitre II commence par un aperçu général de l'adsorption non-covalente de polymères sur la surface de NTC, suivi d'une description détaillée de l'étude réalisée sur la fonctionnalisation non covalente des nanotubes de carbone avec divers liquides ioniques polymérisable (LIP) à base d'imidazolium. Dans ce cadre, nous avons comparé deux méthodes expérimentales: la polymérisation in situ et le mélange en solution. Une des applications les plus importantes des NTC se situe dans le domaine des nanocomposites polymères/NTC. Le chapitre III décrit la formation de composites polyetherimide/NTC à partir des NTC-LIP obtenue dans la chapitre II. La préparation des composites en utilisant la méthode dite « solvent casting » est détaillée. Les NTC bruts, oxydés à l'acide nitrique et fonctionnalisé par le LIP ont été comparés. Des mesures mécaniques, thermiques et électriques de ces composées ont été aussi réalisées. Le dernier chapitre, divisé en deux sections, traite de la fonctionnalisation covalente des nanotubes de carbone avec une variété de polymères en utilisant deux approches différentes: "grafting from" et "grafting to". En utilisant la première approche, nous avons réalisé la croissance de chaînes de polyamide (PA) à partir de la surface de nanotubes de carbone fonctionnalisés avec le caprolactame par polymérisation anionique par ouverture de cycle. Les propriétés de traction des composites à base de PA ainsi préparées ont été étudiées. La polymérisation radicalaire de monomères vinyliques à base de LI de type imidazolium greffés à la surface de NTC est également présentée dans cette partie. Dans la deuxième partie du chapitre IV, nous présentons plusieurs stratégies de fonctionnalisation, y compris l'addition radicalaire et le greffage sur les défauts de NTC, pour la préparation des NTC fonctionnalisés de manière covalente avec des polymères compatibles avec des matrices époxy / This thesis deals with the surface modification of multi-walled carbon nanotubes with polymers with the aim to achieve a high level of dispersion in polymer matrices. Chapter I gives a comprehensive review of the state of the art of hybrids of ionic liquids with carbon nanomaterials, particularly, nanotubes and more recently, graphene. Chapter II starts with a general overview of the non-covalent adsorption of polymers onto the CNT surfaces followed by a detailed description of the study carried out on the non-covalent functionalization of CNTs with various imidazolium based polymerized ionic liquids (PIL). For this purpose, we further compare the two experimental methods: in situ polymerization and solution mixing. One of the most important applications of CNT is in polymer/CNT composites. Chapter III describes the formation of polyetherimide/CNT composites starting from PIL-CNT hybrids obtained in Chapter II. The preparation and characterization of composites using solvent casting methods have been detailed. Pristine, acid oxidized and PIL functionalized CNTs have been compared. Mechanical, thermal and electrical property measurements on these composites have also been described. The last chapter – Chapter IV, divided into two sections, discusses the covalent functionalization of CNTs with a variety of polymers using two main approaches: “grafting from” and “grafting to”. Using the first approach we have grown polyamide (PA) chains from the surface of caprolactam grafted CNTs by anionic ring opening polymerization. The tensile properties of the PA based composites prepared therefrom containing pristine, amine- and PA-functionalized CNTs have been investigated. The radical polymerization of vinyl imidazolium based IL monomers attached to the activated CNT surface is also given in this section. In the second part of Chapter IV, we have reported several “grafting to” functionalization strategies including radical addition and “defect site” grafting used for the preparation of CNTs covalently attached with polymers intended to blend well with epoxy matrices

The sharply rising level of atmospheric carbon dioxide resulting from anthropogenic emissions is one of the greatest environmental concerns facing our civilization today. Metal-organic frameworks (MOFs) are a new class of materials that constructed by metal-containing nodes bonded to organic bridging ligands. MOFs could serve as an ideal platform for the development of next generation CO2 capture materials owing to their large capacity for the adsorption of gases and their structural and chemical tunability. The ability to rationally select the framework components is expected to allow the affinity of the internal pore surface toward CO2 to be precisely controlled, facilitating materials properties that are optimized for the specific type of CO2 capture to be performed (post-combustion capture, precombustion capture, or oxy-fuel combustion) and potentially even for the specific power plant in which the capture system is to be installed. For this reason, significant effort has been made in recent years in improving the gas separation performance of MOFs and some studies evaluating the prospects of deploying these materials in real-world CO2 capture systems have begun to emerge. We have developed six new MOFs, denoted as IFPs (IFP-5, -6, -7, -8, -9, -10, IFP = Imidazolate Framework Potsdam) and two hydrogen-bonded molecular building block (MBB, named as 1 and 2 for Zn and Co based, respectively) have been synthesized, characterized and applied for gas storage. The structure of IFP possesses 1D hexagonal channels. Metal centre and the substituent groups of C2 position of the linker protrude into the open channels and determine their accessible diameter. Interestingly, the channel diameters (range : 0.3 to 5.2 Å) for IFP structures are tuned by the metal centre (Zn, Co and Cd) and substituent of C2 position of the imidazolate linker. Moreover hydrogen bonded MBB of 1 and 2 is formed an in situ functionalization of a ligand under solvothermal condition. Two different types of channels are observed for 1 and 2. Materials contain solvent accessible void space. Solvent could be easily removed by under high vacuum. The porous framework has maintained the crystalline integrity even without solvent molecules. N2, H2, CO2 and CH4 gas sorption isotherms were performed. Gas uptake capacities are comparable with other frameworks. Gas uptake capacity is reduced when the channel diameter is narrow. For example, the channel diameter of IFP-5 (channel diameter: 3.8 Å) is slightly lower than that of IFP-1 (channel diameter: 4.2 Å); hence, the gas uptake capacity and Brunauer-Emmett-Teller (BET) surface area are slightly lower than IFP-1. The selectivity does not depend only on the size of the gas components (kinetic diameter: CO2 3.3 Å, N2 3.6 Å and CH4 3.8 ) but also on the polarizability of the surface and of the gas components. IFP-5 and-6 have the potential applications for the separation of CO2 and CH4 from N2-containing gas mixtures and CO2 and CH4 containing gas mixtures. Gas sorption isotherms of IFP-7, -8, -9, -10 exhibited hysteretic behavior due to flexible alkoxy (e.g., methoxy and ethoxy) substituents. Such phenomenon is a kind of gate effects which is rarely observed in microporous MOFs. IFP-7 (Zn-centred) has a flexible methoxy substituent. This is the first example where a flexible methoxy substituent shows the gate opening behavior in a MOF. Presence of methoxy functional group at the hexagonal channels, IFP-7 acted as molecular gate for N2 gas. Due to polar methoxy group and channel walls, wide hysteretic isotherm was observed during gas uptake. The N2 The estimated BET surface area for 1 is 471 m2 g-1 and the Langmuir surface area is 570 m2 g-1. However, such surface area is slightly higher than azolate-based hydrogen-bonded supramolecular assemblies and also comparable and higher than some hydrogen-bonded porous organic molecules. / Metallorganische Gerüstverbindungen (MOFs) sind eine neue Klasse von porösen Koordinationspolymeren, die aus Metall-Knoten und verbrückenden Liganden bestehen. MOFs können Gasgemische trennen und Gase speichern. Aufgrund ihres modularen Aufbaus können die MOF-Eigenschaften systematisch variiert werden. Ein wichtiges Ziel für das Design von MOFs ist die Synthese von Materialien, die eine hohe selektive Aufnahmefähigkeit und -kapazität für Kohlenstoffdioxid besitzen. Im Rahmen der Arbeit ist es gelungen sechs neue MOFs (IFP-5, -6, -7, -8, -9 und -10) zu synthetisieren. Diese MOFs tragen die Kurzbezeichnung IFP. IFP steht als Abkürzung für Imidazolat-Framework-Potsdam (Imidazolat-basierte Gerüstverbindung Potsdam). In diesen IFPs wurde der Metallknoten (Zink, Cobalt, Cadmium) und der Brückenligand, ein 2-substituiertes Imidazolat-amid-imidat, in der Position variiert, um gute und selektive Sorptionseigenschaften für Kohlenstoffdioxid zu erzielen. Von den synthetisierten Verbindungen hat das IFP-5 die besten Sorptionseigenschaften für Kohlenstoffdioxid. Es konnte weiter gezeigt werden, dass sich die IFP-Struktur bei der Wahl von geeigneten Substituenten 2, wie z.B. Methoxy und Ethoxy auch für das Design von gate-opening (Tür-öffnenden) Effekten eignet. Diese Effekte können wiederum genutzt werden, um selektiv Gasmischungen zu trennen. Wenn man das 4,5-Dicyano-2-methoxy-imidazol in Gegenwart von Zink- und Cobalt-Salzen unter solvothermalen Bedingungen zur Reaktion bringt, erhält man beispiellose supramolekulare Wasserstoffbrückenbindungen zu einem dreidimensionalen Netzwerk, die mit Kanälen verknüpft sind. Diese Kanäle können von Lösungsmittelmolekülen (Wasser und Dimethylformamid) befreit werden und Gase aufnehmen. Insgesamt besteht nun die neue MOF-Klasse der Imidazolat-basierten IFPs aus Vertretern. Das Potential der 2-substituierten 4,5-Dicyanoimidazole ist nicht nur auf die Bildung von porösen Koordinationspolymeren beschränkt, sondern kann auch für die Synthese von bisher unbekannten supramolekularen Strukturen genutzt werden.

This dissertation serves to study a protein's conformation-function relationship since immobilized proteins often behave differently from their solution-state counterparts. Therefore, this study is important to the application of protein-based biodevices. Another aim of this dissertation is to explore a new approach to realize low voltage electrowetting without the help of oil bath. Utilizing this approach, a protein micro-separation was realized. Additionally, the interfacial properties of ionic liquid (IL) solid-like layer, which played a key role in electrowetting, was studied for further developments of IL-based applications. Atomic Force Microscopy (AFM) was utilized in the study and played multiple roles in this dissertation. First, AFM was used as a fabrication tool. In the contact mode, conductive AFM tip was used to conduct the electrochemical oxidation to create a chemical pattern or to conduct an electrowetting experiment. Subsequently, AFM was used as a characterization tool in the tapping mode to characterize the surface structure, the thickness, and the surface potential. Furthermore, AFM in the contact mode was used as a measurement tool to measure the tribological force properties of sample. The results of the study concerning the conformational change in immobilized calmodulin showed that the immobilized CaM retained its activity. Additionally, the immobilization of CaM on a solid support did not interfere with the ability of the protein to bind calcium, as well as CaM kinase binding domain. For the electrowetting experiment, our data suggested that the ultra-high capacitance density of the IL dielectric layer leads to the low voltage electrowetting. We also successfully demonstrated the streptavidin and GFP proteins separation by Electrowetting-on-Dielectric (EWOD) force. The results of the surface properties study indicated that the charge and dipole of the substrate can influence the structures and properties of the IL interfacial layer. Our study would be beneficial in research and assay work involving engineered proteins, as well as the study and development of electrowetting applications.

Les réactions de cycloisomérisation d’énynes catalysées par les métaux de transition sont de puissants outils en synthèse organique: elles donnent accès, en une seule étape économe en atomes, à une variété de structures intéressantes mono- ou bicycliques, comportant des motifs 1,4-diène, 1,3-diène, cyclobutène ou cyclopropane. Afin d’accéder à de nouvelles molécules dérivées de monoterpènes, des 1,6- et 1,7-énynes à pont oxygène ont été préparés à partir de l’alcool péryllique, du nérol et de l’isopulégol, et leur réactivité dans les réactions de cycloisomérisation catalysées par des sels ou des complexes des métaux de transition a été étudiée. De nouvelles molécules bi- et tricycliques contenant des motifs cyclopropane, 1,3- ou 1,4-diènes ont ainsi été synthétisées. Toutes ces molécules ont été purifiées et caractérisées par RMN techniques. Différents systèmes catalytiques décrits dans la littérature ont été comparés : PtCl2, AuCl3, [AuCl(PPh3)/AgPF6] et Rh2Cl2(CO)4. Nous avons ainsi pu montrer que la nature du produit de la réaction dépendait surtout de la structure de l’ényne initial mais aussi du catalyseur mis en jeu. De plus nous avons mis en évidence que la cinétique et la sélectivité pouvaient être modifiées lorsque les réactions étaient faites sous une atmosphère de CO. Dans un second temps, une version asymétrique de la réaction a été explorée dans le cas de l’1,6- ényne dérivé de l’alcool péryllique, en préparant des complexes du platine ou de l’or portant des ligands phosphorés chiraux. L’excès diastéréoisomérique observé sur les deux cyclopropanes obtenus a ainsi pu être augmenté dans le cas des complexes de l’or (I), mais les valeurs restent encore modestes. Enfin, nous avons entrepris une étude préliminaire de la réaction de cycloisomérisation en milieu liquide ionique dans le but de concevoir un système efficace de recyclage du catalyseur. Différents liquides ioniques et différents solvants d’extraction ont été testés pour la réaction avec l’1,6-ényne dérivé de l’alcool péryllique. L’activité et la sélectivité des différents catalyseurs se sont avérées modifiées par rapport à la réaction dans le solvant toluène et des problèmes de reproductibilité sont apparus. Cette étude devra être poursuivie afin d’optimiser les conditions de réaction et de recyclage. / The transition metals catalyzed cycloisomerization reactions of enynes are a powerful tool in organic synthesis: they give access, in only one atom-economic step, to a variety of interesting mono- or bicyclic structures, comprising 1,4-diene, 1,3-diene, cyclobutene or cyclopropane moieties. In order to reach new molecules derived from monoterpenes, O-tethered 1,6- and 1,7- enynes were prepared starting from perillyl alcohol, nerol and isopulegol, and their reactivity in cycloisomerization reactions catalyzed by transition metals salts or complexes was studied. New bi- and tricyclic molecules containing cyclopropane, 1,3- or 1,4-dienes moieties were thus synthesized. All these molecules were purified and characterized by NMR techniques. Various catalytic systems described in the literature were compared: PtCl2, AuCl3, [AuCl(PPh3)/AgPF6] and Rh2Cl2(CO)4. We thus could show that the nature of the final product depended especially on the starting enyne structure but also on concerned catalyst. Moreover we highlighted that kinetics and selectivity could be modified under CO atmosphere. Analogously, an asymmetrical version of the reaction was explored in the case of the 1,6-enyne derived from perillyl alcohol by preparing platinum or gold complexes with chiral phosphorated ligands. The observed diastereoisomeric excess on two obtained cyclopropanes thus could be increased in the case of gold (I) complexes, but the values remain still modest. Finally, we undertook a preliminary study of the cycloisomerization reaction in ionic liquid with an aim of conceiving an effective system for catalyst recycling. Various ionic liquids and different extraction solvents were tested for 1,6-enyne derived from perillyl alcohol. The activity and the selectivity of various catalysts proved, resulted modified compared to the reaction in toluene and reproducibility problems appeared. This study will have to be continued in order to optimize the conditions of reaction and the catalysts recycling.

L’électrochromisme est le changement réversible de couleur d’un matériau lors de son oxydation ou de sa réduction électrochimique. Cette thèse porte sur l’étude d’électrolytes à base de liquide ionique (BMIPF6 et BMITFSI), de sel de lithium (LiTFSI) et de polymère (PMMA) et sur la préparation de systèmes électrochromes à base de ces électrolytes et du PEDOT, du Bleu de Prusse ou d'InHCF comme matériaux électrochromes. La conduction ionique mesurée par EIS, les analyses thermo gravimétriques, les spectroscopies IR et Raman et la mesure des coefficients de diffusion informent sur les interactions entre les espèces dans l'électrolyte. Les matériaux électrochromes (PEDOT, BP, InHCF) sont ensuite étudiés dans un électrolyte modèle LiTFSI 0.03 / BMITFSI 0.97. Enfin, des systèmes électrochromiques flexibles sont réalisés et leur propriétés de coloration et de cyclage étudiées. / Electrochromism is the reversible colour change of a material upon electrochemical oxidation or reduction. This thesis will focus on the study of ionic liquid (BMIPF6 and BMITFSI), lithium salt (LiTFSI) and polymer (PMMA) based electrolytes and on the preparation of electrochromic devices with PEDOT, Prussian Blue or one of its analogues InHCF, as electrochromic materials. The measurement of ionic conductivity by EIS, thermo-gravimetric analysis, IR and Raman spectroscopy and measurement of diffusion coefficients of these electrolytes highlight the interactions between the different species of the electrolyte. Electrochromic materials (PEDOT, BP, InHCF) are then studied in a model electrolyte (LiTFSI 0.03 / 0.97 BMITFSI), their electrochromic properties are detailed. Finally, flexible electrochromic devices are made and their properties of colouration and cycling are presented.

Doctor of Philosophy / Department of Chemical Engineering / Jennifer L. Anthony / Ionic liquids are low melting salts composed of an organic cation and an inorganic or organic anion. Ionic liquids are of interest for their wide range of applications and unique properties, such as the negligible vapor pressure of some types of ionic liquids, and the ability to modify ionic liquid properties by selection of the cation or anion. It has been hypothesized that over one million binary ionic liquids (meaning a single cation/anion pair) are possible. Due to the vast number of potential combinations, it should be possible to design ionic liquids specifically for an application of interest. One potential application is their use as protein solvents. However there is little understanding of how ionic liquids affect proteins. This research examined the solubility and secondary structure of the hydrophobic corn protein zein in seven ionic liquids and three conventional solvents as a function of temperature and solvent properties. Zein’s solubility in the solvents was measured gravimetrically from 30 to 60 degrees Celsius. Solubility was then related to solvent properties to gain an understanding of what solvent properties are important, and how to design an ionic liquid to dissolve zein. It was found that a good solvent for zein has a small molecular volume, a low polarity, and is a weak hydrogen bond acceptor. Infrared spectroscopy with curve fitting was used to examine the secondary structure of zein as a function of both solvent and temperature from 25 to 95 degrees Celsius. It was found that most of the ionic liquids change zein’s secondary structure, but those secondary structure changes were not affected by temperature. Aprotic ionic liquids increase the amount of β-turn secondary structure through non-polar interactions between the mixed aromatic-alkyl imidazolium cations and the non-polar portions of the zein. Strong hydrogen bond accepting molecules were found to increase the amount of β-turn secondary structure. It is hypothesized from this research that suitable solvents for zein will have a small molar volume, low polarity, and be poor hydrogen bond acceptors. This combination of properties will enhance zein’s solubility and limit secondary structure changes that can harm protein properties.

L'électrorhéologie est un domaine où les possibilités d'accroître les performances en utilisant des composés hybrides organiques-inorganiques ont été explorées. Les fluides électrorhéologiques sont des dispersions de particules colloïdales facilement polarisables par un champ électrique dans un liquide non conducteur. Lorsqu'un champ électrique est appliqué les propriétés rhéologiques changent et la viscosité apparente peut augmenter ou diminuer en fonction du type de particules présentes dans le fluide. Ces fluides appartiennent à la classe des matériaux intelligents qui ont un grand potentiel technologique avec des applications dans de nombreux domaines comme l'automobile, l'hydraulique, les joints d'étanchéité, la robotique, le spatial et même en médecine. Dans ce travail on s'intéresse à trois différentes sortes d'hybride: des silicates avec des molécules organiques (ORMOSIL) modifiés par des groupements mercaptan, des liquides ioniques encapsulés dans la silice, et des fibres de sépiolite recouvertes de polyaniline. Pour la synthèse des particules à base de silice (ORMOSIL) et les liquides ioniques encapsulés dans la silice, on a utilisé le procédé sol-gel. Dans le cas de la polyaniline sur la sépiolite, deux méthodes de polymérisation ont été utilisées: en phase solide et en suspension. Tous les systèmes étudiés ont présenté une réponse électrorhéologique. Parmi eux l'hybride polyaniline/sépiolite a fourni la meilleure réponse électrorhéologique, sans doute à cause de la forme allongée des particules, qui donne une contrainte seuil plus grande que les formes sphériques obtenues pour les hybrides à base de silice. / Electrorheology is an area has been exploring the application of these organic-inorganic hybrid compounds, to obtain better performance in electrorheological properties. Electro-rheological fluids consist of a colloidal dispersion, where the liquid is non-conductive and the particles dispersed in the fluid are able of polarized at presence of electric field. When the fluids ER are subjected to an external electric field the rheological properties change, and may increase or decrease the apparent viscosity, it depending on the type of particle present in the fluid. These fluids fall into the class of smart materials witch were of great technological interest, since they are finding applications in: automotive industrial, hydraulics industrial, fluid sealing, robots, aerospace and medicine, among others. In this work were discussed three different kinds of hybrids: organically modified silanes (ORMOSIL) modified with mercaptans groups, ionic liquid encapsulated by silica and sepiolite fibers coated by polyaniline. For the synthesis of particles concerned silica (ORMOSIL and ionic liquid encapsulated by silica) the sol-gel process was used. In the case of polyaniline and sepiolite two synthetic methods of polymerization were applied: bulk and slurry. All systems studied presented electrorheological response. Among them, the polyaniline/sepiolite hybrid materials was provided the best electrorheological response, probably due to its elongated morphology supplied the yield stress greater than spherical morphologies, which were obtained for silica hybrids.

Ayant une partie hydrophile et une partie hydrophobe, les tensioactifs peuvent s'adsorber sur des interfaces et d'abaisser la tension interfaciale (γ), ce qui améliore les propriétés interfaciales. Tensioactifs chargés sont également utilisés dans des applications biologiques, par exemple dans la livraison de gènes. Dans cette thèse, nous avons étudié les propriétés d'adsorption des tensioactifs, à la fois aux interfaces air/eau et sur l'ADN pour former des complexes.La première partie de la thèse se concentre sur les études d'interface de tensioactifs. Pour comprendre comment ils fonctionnent dans ces applications, il est important de connaître les échelles de temps de l'adsorption et la désorption de surfactant. Ainsi, il est nécessaire d'étudier l'adsorption et la cinétique de désorption, qui sont déjà largement étudié. Cependant, les études traditionnelles ont tendance à faire de nombreuses hypothèses, par exemple, l'extension de l'applicabilité des relations d'équilibre à des cas de non-équilibre. Dans cette mémoire, l'adsorption des deux systèmes tensioactifs différents a été étudiée, C12E6 de tensioactif non ionique et d'agent tensio-actif ionique CTAB avec suffisamment de sel. Une mesure de la compression de la bulle unique combiné avec une tension superficielle d'équilibre connue (γeq) de valeur permet de déterminer γ(Γ), ce qui est plus précis que les résultats des méthodes traditionnelles. Les concentrations de surface en fonction du temps sont mesurés, ce qui montre que l'adsorption est contrôlée par la diffusion à temps courts.Après avoir montré que l'adsorption est contrôlée par diffusion, nous rapportons la désorption des tensioactifs à partir de l'interface air/eau pour différents systèmes. Les processus de désorption sont confirmées pas être purement limitée par diffusion, indiquant la présence d'une barrière d'énergie. La barrière d'énergie est influencée par la longueur de la chaîne alkyle, et non le type de contre-ion.Dans la deuxième partie de la thèse, nous nous concentrons sur les systèmes d'ADN/tensioactif. Bien que l'interaction entre les tensioactifs cationiques et anioniques polyélectrolyte a été largement étudiée, il reste nécessaire de mieux comprendre le système complexe, en particulier pour rationaliser le choix des tensioactifs pour atteindre une capacité de liaison de l'ADN contrôlable et une faible toxicité pour l'organisme. Dans cette thèse, nous avons lancé l'enquête systématique sur les interactions des deux tensioactifs cationiques avec l'ADN.Le premier tensioactif utilisé est un gemini tensioactifs cationiques 12-2-12∙2Br. Avant de l'utiliser avec l'ADN d'une caractérisation approfondie a été effectuée. L'équilibrage du 12-2-12∙2Br sur une interface air/eau en l'absence d'électrolyte est très lent. Ajout de NaBr affecte peu la cinétique d'adsorption à des temps courts, pendant lesquels l'adsorption de diffusion. Cependant, l'adsorption s'équilibre beaucoup plus rapide. La formation de micelles de tensioactif cationique gemini 12-3-12∙2Br a été étudiée. La concentration micellaire critique (CMC) augmente légèrement avec la température et diminue avec la force ionique. 12-3-12∙2Br interagit fortement avec l'ADN, en raison de l'attraction électrostatique entre les deux et les interactions hydrophobes entre les chaînes alkyles. Sel écrans l'attraction électrostatique, tout en augmentant la longueur d'écartement des Gémeaux tensioactif affaiblit son interaction avec l'ADN.Un autre agent a également été étudié pour sa capacité de liaison à l'ADN et nous présentons une étude systématique sur les interactions entre tensioactif cationique liquide ionique [C12mim]Br et de l'ADN par des techniques expérimentales et de dynamique moléculaire (MD) de simulation. En ajoutant [C12mim]Br, les chaînes d'ADN sont soumis à compactage, des changements conformationnels, avec le changement de charge nette portée par le complexe ADN/tensioactif. simulation de MD confirme les résultats expérimentaux. / Bearing a hydrophilic part and a hydrophobic part, surfactants can adsorb onto interfaces and lower the interfacial tension (γ), thereby enhancing the interfacial properties and leading to the applications in cleaning, surface functionalization, foaming and emulsification. Charged surfactants are also used in biological applications, in particular to extract and purify DNA, or for gene delivery. In this thesis we have studied the adsorption properties of surfactants, both to air/water interfaces and onto DNA to form complexes. The first part of the thesis concentrates on interfacial studies of surfactants. To understand how they work in these applications it is important to know the time-scales of the surfactant adsorption and desorption. Thus it is necessary to investigate the adsorption and desorption kinetics, which are already widely studied. However, traditional studies tend to make many assumptions, for example, extending the applicability of equilibrium relations to non-equilibrium cases. In this dissertation, the adsorption of two different surfactant systems has been investigated, non-ionic surfactant C12E6 and ionic surfactant CTAB with sufficient salt. A single bubble compression measurement combined with a known equilibrium surface tension (γeq) value allows the determination of γ(Γ), which is more accurate than results from traditional methods. The time-dependent surface concentrations are measured, showing that the adsorption is diffusion controlled at short times.Having shown that adsorption is diffusion controlled, we report desorption of surfactants from the air/water interface for different systems. The desorption processes are confirmed not to be purely diffusion-limited, showing the presence of an energy barrier. The energy barrier is influenced by the alkyl chain length, but not the counterion type.In the second part of the thesis we concentrate on DNA/surfactant systems. Although the interaction between cationic surfactant and anionic polyelectrolyte has been extensively studied, there still remains need to further understand the complex system, especially to rationalize the choice of surfactants to reach controllable DNA binding ability and low toxicity to the organism. In this dissertation, we introduced the systematic investigation on the interactions of two cationic surfactants with DNA.The first surfactant used is a cationic gemini surfactant 12-2-12∙2Br. Before using it with DNA a thorough characterization has been carried out. The equilibration of 12-2-12∙2Br onto an air/water interfaces in the absence of electrolyte is very slow. Addition of NaBr hardly affects the adsorption kinetics at short times, during which the adsorption is diffusive. However, the adsorption equilibrates much faster. The micellization of cationic gemini surfactant 12-3-12·2Br has been investigated. The critical micelle concentration (CMC) increases slightly with temperature and decreases with ionic strength. 12-3-12·2Br interacts strongly with DNA, due to the electrostatic attraction between the two and the hydrophobic interactions between alkyl chains. Salt screens the electrostatic attraction, while increasing spacer length of gemini surfactant weakens its interaction with DNA.Another surfactant has also been studied for its DNA binding ability and we present a systematic study on interactions between cationic ionic liquid surfactant [C12mim]Br and DNA by experimental techniques and Molecular Dynamics (MD) simulation. By adding [C12mim]Br, DNA chains undergo compaction, conformational changes, with the change of net charges carried by the DNA/surfactant complex. MD simulation confirms the experimental results.