This Thesis presents studies of molecular association in aqueous solution and at the liquid/solid interface. The investigated molecular systems range from self-aggregating surfactants to hydration water in contact with micelles or individual molecules. In most studies, combinations of various NMR methods were applied. These vary from simple chemical shift and intensity measurements to more elaborate self-diffusion and intermolecular cross-relaxation experiments. Non-ideal mixed micelles of fluorinated and hydrogenated surfactants were studied by an experimental procedure that allows an analysis in terms of micellar structure, using a minimal number of initial assumptions. Quantitative conclusions about micro-phase separation within mixed micelles were obtained within the framework of the regular solution theory. Additionally, NMR was introduced and developed as a powerful method for studying adsorption of surfactants at solid interfaces. Adsorption isotherms for pure and mixed surfactant systems and non-ideal mixing behavior of fluorinated and hydrogenated surfactants at solid surfaces were quantified. Fluorosurfactant-protein association was investigated using the methods described. Intermolecular cross-relaxation rates between solute and solvent molecules were recorded at several different magnetic fields. The results reveal strong frequency dependence for both small molecules and micelles. This finding demonstrates that intermolecular cross-relaxation is not solely controlled by fast local motions, but also by long-range translational dynamics. Data analysis in terms of recently developed relaxation models provides information about the hydrophobic hydration and micellar structure. / QC 20100914

In this work new fluorinated and non-fluorinated mono- and bifunctional trithiocarbonates of the structure Z-C(=S)-S-R and Z-C(=S)-S-R-S-C(=S)-Z were synthesized for the use as chain transfer agents (CTAs) in the RAFT-process. All newly synthesized CTAs were tested for their efficiency to moderate the free radical polymerization process by polymerizing styrene (M3). Besides characterization of the homopolymers by GPC measurements, end- group analysis of the synthesized block copolymers via 1H-, 19F-NMR, and in some cases also UV-vis spectroscopy, were performed attaching suitable fluorinated moieties to the Z- and/or R-groups of the CTAs. Symmetric triblock copolymers of type BAB and non-symmetric fluorine end- capped polymers were accessible using the RAFT process in just two or one polymerization step. In particular, the RAFT-process enabled the controlled polymerization of hydrophilic monomers such as N-isopropylacrylamide (NIPAM) (M1) as well as N-acryloylpyrrolidine (NAP) (M2) for the A-blocks and of the hydrophobic monomers styrene (M3), 2-fluorostyrene (M4), 3-fluorostyrene (M5), 4-fluorostyrene (M6) and 2,3,4,5,6-pentafluorostyrene (M7) for the B-blocks. The properties of the BAB-triblock copolymers were investigated in dilute, concentrated and highly concentrated aqueous solutions using DLS, turbidimetry, 1H- and 19F-NMR, rheology, determination of the CMC, foam height- and surface tension measurements and microscopy. Furthermore, their ability to stabilize emulsions and microemulsions and the wetting behaviour of their aqueous solutions on different substrates was investigated. The behaviour of the fluorine end-functionalized polymers to form micelles was studied applying DLS measurements in diluted organic solution. All investigated BAB-triblock copolymers were able to form micelles and show surface activity at room temperature in dilute aqueous solution. The aqueous solutions displayed moderate foam formation. With different types and concentrations of oils, the formation of emulsions could be detected using a light microscope. A boosting effect in microemulsions could not be found adding BAB-triblock copolymers. At elevated polymer concentrations, the formation of hydrogels was proved applying rheology measurements. / Im Rahmen dieser Arbeit wurden neue fluorierte und unfluorierte mono- und bifunktionelle Trithiocarbonate der Typen Z-C(=S)-S-R und Z-C(=S)-S-R-S-C(=S)-Z zur Anwendung als CTAs (chain- transfer agents) im RAFT-Polymerisationsverfahren hergestellt. Alle CTAs wurden erfolgreich auf ihre Effizienz zur Steuerung des radikalischen Polymerisationsverfahrens hin durch Polymerisation von Styrol (M3) getestet. Neben GPC-Messungen wurden Endgruppenanalysen der synthetisierten Blockcopolymere mittels 1H-, 19F-NMR und in manchen Fällen auch UV-Vis Spektroskopie durchgeführt. Dazu wurden die Z- und/oder R-Gruppen der CTAs mit geeigneten fluorierten Gruppen versehen. Durch Anwendung des RAFT Verfahrens konnten symmetrische Triblockcopolymere vom Typ BAB bzw. mit einer Fluoralkylgruppe endgecappte unsymmetrische Polymere in nur zwei bzw. einem Polymerisationsschritt hergestellt werden. Das RAFT- Polymerisationsverfahren ermöglicht sowohl die Polymerisation hydrophiler Monomere wie N-Isopropylacrylamid (NIPAM) (M1) oder N-Acryloylpyrrolidin (NAP) (M2) für die A-Blöcke als auch der hydropoben Monomere Styrol (M3), 2-Fluorostyrol (M4), 3-Fluorostyrol (M5), 4- Fluorostyrol (M6) und 2,3,4,5,6- Pentafluorostyrol (M7) für die B-Blöcke. Die Eigenschaften der Blockcopolymere in verdünnten, konzentrierten und hochkonzentrierten wässrigen Lösungen wurden mittels DLS, Trübungsphotometrie, 1H- und 19F-NMR, Rheologie, CMC- sowie Schaumhöhen- und Oberflächenspannungsmessungen und Lichtmikroskopie untersucht. Weiterhin wurden ihre Eigenschaften als Emulgatoren und in Mikroemulsion untersucht. Das Micellbildungsverhalten der hydrophob endfunktionalisierten Polymere wurde mittels DLS Messungen in verdünnter organischer Lösung untersucht. Alle untersuchten BAB-Triblöcke bildeten Micellen und zeigten Oberflächenaktivität bei Raumtemperatur in verdünnter, wässriger Lösung. Weiterhin zeigen die wässrigen Lösungen der Polymere mäßige Schaumbildung. Mit verschiedenen Öltypen und Ölkonzentrationen wurden Emulsionen bzw. Mikroemulsionen gebildet. In Mikroemulsion wurde durch Zugabe von BAB-Triblockopolymeren kein Boosting-Effekt erzielt werden. Bei Untersuchung höherer Polymerkonzentrationen wurde die Bildung von Hydrogelen mittels rheologischer Messungen nachgewiesen. Verschiedene Substrate konnten benetzt werden. Die hydrophob endgecappten Polymere bilden in verdünnter organischer Lösung Micellen, die mittels DLS untersucht wurden, und zeigen somit Tensidverhalten in nichtwässriger Lösung.

High-Gradient Magnetic Separation (HGMS) is a powerful separation process that has great potential for industrial wastewater treatment, particularly for the removal and recovery of paramagnetic colloidal particles. The chief advantages of HGMS are that the separation is reversible and potentially selective. However, these advantages are compromised if non-magnetic filtration mechanisms influence significantly the capture of particles. The objective of this study was to identify the chief mechanisms responsible for the removal of ferric oxide (Fe2O3) from water by an HGMS process. This objective was achieved by measuring the effects of applied magnetic induction, collector radius, and fluid velocity on the removal efficiency (RE) of a stainless-steel filter column. These factors were tested on the removal of bare Fe2O3 particles and particles treated with a surfactant (sodium dodecyl sulfate, SDS). The results were compared to the predictions of a trajectory model which simulates particle capture by a magnetic force. The experimental results show that non-magnetic force mechanisms are primarily responsible for the removal of bare Fe2O3 particles for the experimental conditions used in this work. For these particles, the three factors tested had no significant effect on the RE, and 90.1% of the particles were removed without a magnetic force. These results differed sharply from modeling predictions. However, the magnetic force mechanism is primarily responsible for the removal of surfactant-treated Fe2O3 particles. The three factors investigated had a marked effect on the RE, and only 10.8% of the particles were removed without a magnetic force. An increase in magnetic induction from 0.2 to 0.5 T increased the RE from 79.9 to 93.4 %; a decrease in wire radius from 49 to 15 Ym increased the RE from 60.2 to 93.4%, and a decrease in fluid velocity from 0.5 to 0.1 cm/s increased the RE from 69.5 to 95.3%. These results agreed closely with the model predictions.This study demonstrates that by reducing the effect of attractive non-magnetic forces on filtration, surfactant treatment of colloidal particles can potentially preserve and enhance these two key advantages, i.e., regeneration and selectivity of HGMS processes.

Cette thèse décrit deux études expérimentales distinctes sur des couplages originaux entre un cristal liquide et des surfactants.<br />La première étude porte sur l'organisation de systèmes lyotropes (surfactants et eau) dans un solvant thermotrope anisotrope (cristal liquide). L'existence d'une phase baptisée « nématique transparente » dans un tel système mixte thermotrope-lyotrope de type microémulsion a été en effet récemment débattue. Des expériences de diffusion dynamique de lumière, au voisinage de la transition isotrope-nématique, laissait supposer l'apparition d'une phase intermédiaire, résultant de la compétition entre l'apparition d'un ordre nématique dans le solvant et des effets d'ancrages sur les agrégats.<br />Nous avons caractérisé, dans un premier temps, par diffusion de rayonnement X et neutrons, la morphologie et les interactions d'agrégats, composés de bromure de didodecyldimethylammonium (DDAB) et d'eau, dans le cristal liquide 4-n-pentyl-4'-cyanobiphenyl (5CB) en phase isotrope. L'étude de l'évolution des diagrammes de phases couplée à des expériences de diffusion (X, Lumière et neutrons) a permis de montrer que l'ajout de cosurfactants permettait de faire varier continûment la taille des nanoagrégats. L'ensemble de nos données expérimentales s'explique bien par la présence d'interactions fortes de Van der Waals entre micelles, ce qui justifie en particulier l'absence de transition microémulsion/ lamellaire gonflée dans ce système. L'analyse des facteurs de structure a permis par ailleurs de mettre en évidence une seconde interaction attractive entre micelle, causée par les fluctuations paranématiques du cristal liquide, intervenant essentiellement à l'approche de la transition isotrope-nématique du cristal liquide. Nous discutons de cette nouvelle interaction à la lumière des résultats de nos expériences de diffusion.<br />La deuxième étude porte sur les émulsions directes eau-cristal liquide en présence de surfactants amphotropes que nous avons synthétisés et caractérisés par RMN. La formulation de ces surfactants visait à renforcer leur localisation exclusive à l'interface eau-cristal liquide. Les émulsions obtenues montrent la formation spectaculaire de gouttes allongées cylindriques de type filaments. Les propriétés statiques et dynamiques de ces objets ont été explorées et l'origine de cette instabilité est explicitée. La longueur des microtubes est modifiable par des gradients de concentration ou des variations de température ce qui nous a permis de discuter du mécanisme régissant leur morphologie.

Gemini surfactants are versatile gene delivery agents because of their ability to bind and compact DNA and their low cellular toxicity. The aim of my dissertation work was to develop non-invasive mucosal formulations of novel amino acid-substituted gemini surfactants with the general chemical formula C12H25(CH3)2N+-(CH2)3-N(AA)-(CH2)3-N+(CH3)2-C12H25 (AA= glycine, lysine, glycyl-lysine, lysyl-lysine). These compounds were formulated with a model plasmid DNA, encoding for interferon-γ and green fluorescent protein, in the presence of helper lipid, 1,2 dioleyl-sn-glycero-phosphatidyl-ethanolamine. Formulations were assessed in Sf 1 Ep epithelial cells. Among the novel compounds, plasmid/gemini/lipid (P/G/L) nanoparticles formulated using glycine- and glycyl-lysine substituted gemini surfactants achieved significantly higher gene expression than the parent unsubstituted compound. The key physicochemical properties, e.g. size, surface charge, DNA binding, and toxicity of P/G/L complexes were correlated with transfection efficiency. The presence of amino-acid substitution did not interfere with DNA compaction and contributed to an overall low toxicity of all P/G/L complexes, comparable to the parent gemini surfactant. A cellular uptake mechanistic study revealed that both clathrin- and caveolae-mediated uptake were major uptake routes for P/G/L nanoparticles. However, amino acid substitution in the gemini surfactant imparted high buffering capacity, pH-dependent increase in particle size, and balanced DNA binding properties. These properties may enhance endosomal escape of P/12-7NGK-12/L resulting in higher gene expression. Finally, the P/G/L complexes were incorporated into an in-situ gelling dispersion containing a thermosensitive polymer, poloxamer 407, and a permeation enhancer, diethylene glycol monoethyl ether (DEGEE). A 16% w/v poloxamer concentration produced a dispersion that gelled at body temperature and exhibited sufficient yield value to prevent formulation leakage from the vaginal cavity. The formulations were prepared with a model plasmid, encoding for red fluorescent protein, and administered topically to rabbit vagina. In agreement with our in vitro results, confocal microscopy revealed that glycyl-lysine substituted gemini surfactant exhibited higher gene expression compared to the parent unsubstituted gemini surfactant. This provided proof-of-concept for use of amino acid-substituted gemini surfactant in non-invasive mucosal (vaginal) gene delivery systems with potential therapeutic applications. These formulations will be developed with therapeutically relevant genes to assess their potential as genetic vaccines. In addition, new gemini surfactants will be developed by grafting other amino acids via glycine linkage to retain conformation flexibility and enhance endosomal escape of DNA complexes for higher transfection efficiency.

Η ευρωπαϊκή ένωση αναγνωρίζοντας τα προβλήματα που προκαλούνται από την παρουσία ξενοβιοτικών ουσιών στην επεξεργασμενη ιλύ εκδίδει συγκεκριμένες οδηγίες σχετικά με την διάθεση της στο έδαφος. Φαρμακευτικές ουσίες ,LAS ,APE, PAE και PAHs συχνά απαντώνται σε σημαντικές ποσότητες στην ιλύ, πολλές από τις ουσίες είναι παρεμπόδιστες ενώ η επίδραση τους στην λειτουργία των αναερόβιων αντιδραστήρων είναι άγνωστη. Στην εργασία αυτή μελετήθηκε η επίδραση των ρυπαντών αυτών στην διεργασία της αναερόβιας χώνευσης καθώς και η βιοαποδόμηση τους κάτω από αναερόβιες συνθήκες. Η τριχλωζάνη και η οφλοξακίνη παρεμποδίζουν την διαδικασία τησ αναερόβιας χώνευσης αυξάνοντας τα επίπεδα της συγκέντρωσης του διαλυτού χαο. Επίσης ο διαιθυλ(2-εξυλ)φθαλικός εστέρας βιοαποδομείται μερικώς. / Problems related to agricultural recycling of sludge include the presence of pollutants including priority pollutants identified in the EU urban water directives. Pharmaceuticals,LAS ,APE, PAE and PAHs are often present in significant quantities in the sludge. many of these compounds are inhibitory, and the impact on digester performance in unknown. in this work we identify the impact of these pollutants on the anaerobic process. itself, as well as degradation of the target compounds triclosaw and ofloxacin seemed to inhibit the anaerobic digestion process, increasing the dissolved cod concentration rapidly. Dehp was partially degraded. the mass transferrate was rate limiting for functioned as a tank equalizing the concentration of the dehp troughout the solid particle.

Polymer foams belong to the solid foams family which are versatile materials, extensively used for a large number of applications such as automotive, packaging, sport products, thermal and acoustic insulators, tissue engineering or liquid absorbents. Composed of air bubbles entrapped in a continuous solid network, they combine the properties of the polymer with those of the foam to create an intriguing and complex material. Incorporating a foam into a polymer network not only allows one to use the wide range of interesting properties that the polymer offers, but also permits to profit from the advantageous properties of foam including lightness, low density, compressibility and high surface-to-volume ratio. Generally, the properties of polymer foams are strongly related to their density and their structure (bubble size and size distribution, bubble arrangement, open vs closed cells). Having a good control over foam properties is thus achieved by first controlling its density and structure.We developed a technique in which solid foams are generated essentially in a two-step process: a sufficiently stable liquid foam with well-controlled structural properties is generated in a first step, and then solidified in a second one. With such a two-step approach, the generation of solid foams can be divided into a number of well-separated sub-tasks which can be controlled and optimised separately. The transition from liquid to solid state is a sensitive issue of a great importance and therefore needs to be controlled with sufficient accuracy. It is essentially composed of three key steps: foam generation, mixing of reactants and foam solidification and requires the optimisation of foam stability in conjunction with an appropriate choice of both foaming time and solidification time. Furthermore, a good homogeneity of the polymer foam calls for a good mixing of the different reactants involved in the foaming and the polymerisation.A particularly powerful demonstration of the advantages of this approach is given by solidifying monodisperse liquid foams generated using millifluidic technique, in which all bubbles have the same size. In a liquid foam, equal-volume bubbles self-order into periodic, close-packed structures under gravity or confinement. As such, monodisperse foams provide simultaneous control over the size and the organisation of the pores in the final solid with an accuracy which is expected to give rise to a better understanding of the structure-property relationship of porous solids and to the development of new porous materials.We therefore aim to explore the new spectrum of properties, which polymer foams offer when we introduce an ordered structure into them since the most widely used polymer foams nowadays have disordered structures. The goal of our study is to demonstrate the feasibility of this two-step approach for different classes of polymers, including biomolecular hydrogel, superabsorbent polymer and polyurethane.For the generation of the structured polymer foams we use Lab-on-a-Chip technologies which allow the "shrinking" of large-scale set-ups to micro/millimetic scale. It permits also to perform "flow chemistry" in which the various liquid and gaseous ingredients of the foam are injected and mixed in a purpose-designed network of the micro- and millifluidic Lab-on-a-Chip. We adjust this approach according to the requirements of each polymer system, i.e. the foaming and the mixing techniques are chosen to fit the properties of each system, and can be exchanged to fit the properties of the studied systems.

Linear covalently closed (LCC) DNA minivectors serve to be superior to conventional circular covalently closed (CCC) plasmid DNA (pDNA) vectors due to enhancements to both transfection efficiency and safety. Specifically, LCC DNA minivectors have a heightened safety profile as insertional mutagenesis is inhibited by covalently closed terminal ends conferring double-strand breaks that cause chromosomal disruption and cell death in the low frequency event of chromosomal integration. The development of a one-step, E. coli based in vivo LCC DNA minivector production system enables facile and efficient production of LCC DNA minivectors referred to as DNA ministrings. This novel in vivo system demonstrates high versatility, generating DNA ministrings catered to numerous potential applications in gene therapy and vaccine development. In the present study, numerous aspects pertaining to the generation of gene therapeutics with LCC DNA ministrings have been explored with relevance to both industry and clinical settings. Through systematic assessment of induction duration, cultivation strategy, and genetic/chemical modifications, the novel in vivo system was optimized to produce high yields of DNA ministrings at ~90% production efficiency. Purification of LCC DNA ministrings using anion exchange membrane chromatography demonstrated rapid, scalable purification of DNA vectors as well as its potential in the separation of different DNA isoforms. The application of a hydrogel-based strong Q-anion exchange membrane, with manipulations to salt gradient, constituted effective separation of parental supercoiled CCC precursor pDNA and LCC DNA. The resulting DNA ministrings were employed for the generation of 16-3-16 gemini surfactant based synthetic vectors and comparative analysis, through physical characterization and in vitro transfection assays, was conducted between DNA ministring derived and CCC pDNA derived lipoplexes. Differences in DNA topology were observed to induce differences in particle size and DNA protection/encapsulation upon lipoplex formation. Lastly, the in vivo DNA minivector production system successfully generated gagV3(BCE) LCC DNA ministrings for downstream development of a HIV DNA-VLP (Virus-like particle) vaccine, thus highlighting the capacity of such system to produce DNA ministrings with numerous potential applications.

No description available.

Organic-inorganic nanostructured composites are nowadays integrated in the field of material science and technology. They are used as advanced materials directly or as precursors to novel composites with potential applications in optics, mechanics, energy, catalysis and medicine. Many properties of these complex materials depend on conformational rearrangements in their inherently dynamic organic parts. The focus of this thesis is on the study of the molecular mobility in ordered nanostructured composites and lyotropic mesophases and also on the development of relevant solid-state NMR methodologies. In this work, a number of new experimental approaches were proposed for dipolar NMR spectroscopy for characterizing molecular dynamics with atomic-level resolution in complex solids and liquids. A new acquisition scheme for two-dimensional dipolar spectroscopy has been developed in order to expand the spectral window in the indirect dimension while using limited radio-frequency power. Selective decoupling of spin-1 nuclei for sign-sensitive determination of the heteronuclear dipolar coupling has been described. A new dipolar recoupling technique for rotating samples has been developed to achieve high dipolar resolution in a wide range of dipolar coupling strength. The experimental techniques developed herein are capable of delivering detailed model-independent information on molecular motional parameters that can be directly compared in different composites and their bulk analogs. Solid-state NMR has been applied to study the local molecular dynamics of surfactant molecules in nanostructured organic-inorganic composites of different morphologies. On the basis of the experimental profiles of local order parameters, physical motional models for the confined surfactant molecules were put forward. In layered materials, a number of motional modes of surfactant molecules were observed depending on sample composition. These modes ranged from essentially immobilized rigid states to highly flexible and anisotropically tumbling states. In ordered hexagonal silica, highly dynamic conformationally disordered chains with restricted motion of the segments close to the head group have been found. The results presented in this thesis provide a step towards the comprehensive characterization of the molecular states and understanding the great variability of the molecular assemblies in advanced nanostructured organic−inorganic composite materials. / <p>QC 20150225</p>