The properties of a series of well-defined new surfactant oligomers (dimers to tetramers)were examined. From a molecular point of view, these oligomeric surfactants consist of simple monomeric cationic surfactant fragments coupled via the hydrophilic ammonium chloride head groups by spacer groups (different in nature and length). Properties of these cationic surfactant oligomers in aqueous solution such as solubility, micellization and surface activity, micellar size and aggregation number were discussed with respect to the two new molecular variables introduced, i.e. degree of oligomerization and spacer group, in order to establish structure – property relationships. Thus, increasing the degree of oligomerization results in a pronounced decrease of the critical micellization concentration (CMC). Both reduced spacer length and increased spacer hydrophobicity lead to a decrease of the CMC, but to a lesser extent. For these particular compounds, the formed micelles are relatively small and their aggregation number decreases with increasing the degree of oligomerization, increasing spacer length and sterical hindrance. In addition, pseudo-phase diagrams were established for the dimeric surfactants in more complex systems, namely inverse microemulsions, demonstrating again the important influence of the spacer group on the surfactant behaviour. Furthermore, the influence of additives on the property profile of the dimeric compounds was examined, in order to see if the solution properties can be improved while using less material. Strong synergistic effects were observed by adding special organic salts (e.g. sodium salicylate, sodium vinyl benzoate, etc.) to the surfactant dimers in stoichiometric amounts. For such mixtures, the critical aggregation concentration is strongly shifted to lower concentration, the effect being more pronounced for dimers than for analogous monomers. A sharp decrease of the surface tension can also be attained. Many of the organic anions produce viscoelastic solutions when added to the relatively short-chain dimers in aqueous solution, as evidenced by rheological measurements. This behaviour reflects the formation of entangled wormlike micelles due to strong interactions of the anions with the cationic surfactants, decreasing the curvature of the micellar aggregates. It is found that the associative behaviour is enhanced by dimerization. For a given counterion, the spacer group may also induce a stronger viscosifying effect depending on its length and hydrophobicity. Oppositely charged surfactants were combined with the cationic dimers, too. First, some mixtures with the conventional anionic surfactant SDS revealed vesicular aggregates in solution. Also, in view of these catanionic mixtures, a novel anionic dimeric surfactant based on EDTA was synthesized and studied. The synthesis route is relatively simple and the compound exhibits particularly appealing properties such as low CMC and σCMC values, good solubilization capacity of hydrophobic probes and high tolerance to hard water. Noteworthy, mixtures with particular cationic dimers gave rise to viscous solutions, reflecting the micelle growth. / Die Eigenschaften einer Reihe gut definierter neuer oligomerer Tenside (von Dimeren bis zu Tetrameren) wurden untersucht. Strukturell bestehen diese oligomeren Tenside aus einfachen monomeren kationischen Tensidfragmenten, die über die hydrophile Kopfgruppe (Tetraalkyl-Ammoniumchlorid) durch „Spacer“-Gruppen unterschiedlicher Natur und Länge miteinander verbunden/gekoppelt sind. Die Eigenschaften dieser kationischen oligomeren Tenside in wässriger Lösung wie Löslichkeit, kritische Mizellbildungskonzentration und Oberflächenaktivität, Mizellgröße und Aggregationszahl werden in Bezug auf die zwei neuen molekularen Variabeln (d.h. dem Oligomerisationsgrad und der Spacer-Gruppe) untersucht, um Struktur-Eigenschafts-Beziehungen abzuleiten. Die Erhöhung des Oligomerizationsgrads verringert stark die kritische Mizellbildungskonzentration (CMC). Eine kurze Spacer-Länge oder ein erhöhte Hydrophobie des Spacers erniedrigt die CMC ebenfalls, aber in einem geringeren Umfang. Die gebildeten Mizellen sind relativ klein und ihre Aggregationszahl nimmt mit zunehmendem Oligomerisationsgrad ab, genau wie mit zunehmender Spacerlänge oder sterischer Behinderung. Außerdem wurden Pseudo-Phasendiagramme für die Gemini-Tenside in komplexen Systemen, nämlich in inversen Mikroemulsionen untersucht. Auch hier zeigt die Spacer-Gruppe einen großen Einfluß auf das Tensidverhalten. Weiterhin wurde der Einfluss von Zusätzen auf das Eigenschaftsprofil der dimeren Tenside untersucht. Starke Synergien wurden beobachtet, wenn man spezielle organische Anionen (z.B. Natriumsalicylat, Natriumvinylbenzoat, etc.) zu den dimeren Tensiden in stöchiometrischen Mengen hinzugibt. Für solche Mischungen wird die Mizellbildungskonzentration stark zu niedrigen Konzentrationen verschoben, wobei der Effekt für die Dimere ausgeprägter als für die analogen Monomere ist. Eine Verringerung der Oberflächenspannung wird ebenfalls erreicht. Gemini-Tenside mit geeigneten Spacer-Gruppen bilden nach Zugabe ausgewählter organischer Anionen viskoelastische Lösungen, selbst wenn die dimeren Tenside nur über relativ kurz Alkylketten verfügen. Dies wurde mittels rheologischer Messungen gezeigt. Dieses Verhalten resultiert aus der Bildung langer Zylinder-Mizellen aufgrund der starken Wechselwirkung der Anionen mit den kationischen Tensiden, die die Krümmung der mizellaren Strukturen verringern. Es wurde auch festgestellt, dass das assoziative Verhalten durch die Dimerisation erhöht wird. Für ein gegebenes Gegenion kann die Spacer-Gruppe den verdickenden Effekt verstärken, in Abhängichkeit von seiner Länge und Hydrophobie. Als weitere Zusätze wurden entgegengesetzt geladene Tenside wurden mit den kationischen Dimeren kombiniert. Einige Mischungen mit dem käuflichen anionischen Tensid SDS bilden Vesikel in Lösung. Mit Blick auf diese katanionischen Mischungen wurde ein neues anionisches Gemini-Tensid, das auf EDTA basiert ist, synthetisiert und charakterisiert. Der Syntheseweg ist relativ einfach und das Tensid zeigt interessante Eigenschaften wie niedrige CMC- und scmc-Werte, gute Solubilisierungskapazität von hydrophoben Substanzen und hohe Toleranz gegen hartes Wasser. Mischungen dieses anionischen Tensids mit bestimmten kationischen Dimeren bilden visköse Lösungen, was ein starkes Mizell-Wachstum widerspiegelt.

Adsorption layers of soluble surfactants enable and govern a variety of phenomena in surface and colloidal sciences, such as foams. The ability of a surfactant solution to form wet foam lamellae is governed by the surface dilatational rheology. Only systems having a non-vanishing imaginary part in their surface dilatational modulus, E, are able to form wet foams. The aim of this thesis is to illuminate the dissipative processes that give rise to the imaginary part of the modulus. <br><br> There are two controversial models discussed in the literature. The reorientation model assumes that the surfactants adsorb in two distinct states, differing in their orientation. This model is able to describe the frequency dependence of the modulus E. However, it assumes reorientation dynamics in the millisecond time regime. In order to assess this model, we designed a SHG pump-probe experiment that addresses the orientation dynamics. Results obtained reveal that the orientation dynamics occur in the picosecond time regime, being in strong contradiction with the two states model. <br><br> The second model regards the interface as an interphase. The adsorption layer consists of a topmost monolayer and an adjacent sublayer. The dissipative process is due to the molecular exchange between both layers. The assessment of this model required the design of an experiment that discriminates between the surface compositional term and the sublayer contribution. Such an experiment has been successfully designed and results on elastic and viscoelastic surfactant provided evidence for the correctness of the model. <br><br> Because of its inherent surface specificity, surface SHG is a powerful analytical tool that can be used to gain information on molecular dynamics and reorganization of soluble surfactants. They are central elements of both experiments. However, they impose several structural elements of the model system. During the course of this thesis, a proper model system has been identified and characterized. The combination of several linear and nonlinear optical techniques, allowed for a detailed picture of the interfacial architecture of these surfactants. / Amphiphile vereinen zwei gegensätzliche Strukturelemente in einem Molekül, eine hydrophile Kopfgruppe und ein hydrophobe, meist aliphatische Kette. Aufgrund der molekularen Asymmetrie erfolgt eine spontane Adsorption an der Wasser-Luft Grenzfläche. Die Adsorptionsschicht verändert die makroskopischen Eigenschaften des Materials, z.B. die Grenzflächenspannung wird erniedrigt. Amphiphile sind zentrale Bauelemente der Kolloid- und Grenzflächenforschung, die Phänomene, wie Schäume ermöglichen. <br><br> Eine Schaumlamelle besteht aus einem dünnen Wasserfilm, der durch zwei Adsorptionsschichten stabilisiert wird. Die Stabilität der Lamelle wird durch die Grenzflächenrheologie entscheidend geprägt. Die wesentliche makroskopische Größe in diesem Zusammenhang ist das so genannte Grenzflächendilatationsmodul E. Es beschreibt die Fähigkeit des Systems die Gleichgewichtsgrenzflächenspannung nach einer Expansion oder Dilatation der Adsorptionschicht wieder herzustellen. Das Modul E ist eine komplexe Größe, in dem der Imaginärteil direkt mit der Schaumstabilität korreliert. <br><br> Diese Arbeit widmet sich der Grenzflächenrheologie. In der Literatur werden zwei kontroverse Modelle zur Interpretation dieser Größe diskutiert. Diese Modelle werden experimentell in dieser Arbeit überprüft. Dies erfordert die Entwicklung neuer experimenteller Aufbauten basierend auf nichtlinearen, optischen Techniken. Mit diesen Experimenten konnte eines der Modelle bestätigt werden.

Surfactants are molecules that contain a water-soluble and afat-soluble part. They have important functions in productssuch as detergents, cosmetics, pharmaceuticals and foods aswell as in many industrial processes. Surfactants are used onvery large scale, which makes it important to decrease theirimpact on the environment. This can be done by starting withnatural materials, by improving the synthetic methods and byreducing the use of limited resources such as energy andorganic solvents. This thesis focuses on lipase-catalyzed synthesis ofsurfactants based on natural products. It also includesfunctional studies of the produced surfactants; as antioxidantsin oils, or as surfactants to solubilize pharmaceuticals. Unsaturated fatty acid esters of ascorbic acid weresynthesized with catalysis by Candida antarctica lipase B int-amyl alcohol and in ionic liquids. High yields ofascorbyl oleate were obtained in an ionic liquid that wasdesigned to improve the solubility of the fatty acid, when thereaction was performed under vacuum. Ascorbyl oleate wasamorphous and was a better antioxidant than ascorbyl palmitatein rapeseed oil. Polyethylene glycol (PEG) stearate, PEG 12-hydroxystearateand a series of PEG 12-acyloxy-stearates were synthesized in avacuum-driven, solvent-free system usingC. antarcticalipase B as catalyst. Critical micelleconcentration and solubilization capacity were determined forthe PEG 12-acyloxy-stearates. Their effects on living cellswere evaluated in studies of hemolysis and transepithelialelectrical resistance. Several PEG1500 12-acyloxy-stearateswere excellent solubilizers for pharmaceutical use and hadnegligible negative effects on living cells even at highconcentrations. Enzymatic and chemo-enzymatic methods offer uniquepossibilities to synthesize surfactants of high purity. Pureand well-defined surfactants enable new applications and areimportant for the understanding of surfactantstructure-function relationships.

Les propriétés (catalytiques, électriques, optiques ou magnétiques) des métaux ultra-divisés sont différentes du métal massif et sont influencées par la forme et la morphologie des nanomatériaux. Parmi les techniques de synthèses des nanomatériaux, la radiolyse est une méthode de choix pour réduire de façon contrôlée des ions métalliques et pour induire la polymérisation de monomères. Une matrice souple auto-assemblée, à partir de molécules de surfactants, a été employée comme nanoréacteur pour synthétiser des nanostructures (bi-)métalliques ou polymères de morphologie contrôlée. Les surfactants forment dans des conditions particulières des mésophases hexagonales quaternaires qui peuvent être gonflées, de façon continue, sur une large gamme. Le dopage des mésophases en sels métalliques ou en monomères peut être réalisé aussi bien en phase aqueuse qu'en phase organique, permettant d'obtenir des nanostructures de morphologie différentes. En phase aqueuse, la synthèse conduit à la formation de matériaux mésoporeux. Ceux-ci sont d'un intérêt tout particulier pour la catalyse en raison de leur très grande surface spécifique. Le contrôle du gonflement de la mésophase permet un ajustement fin de la porosité dans la structure métallique finale. Nous avons également mis en évidence que la composition de ces nanostructures métalliques Pd/Pt poreuses peut être contrôlée. Nous avons également synthétisé des nanostructures 1D dans la phase organique, comme des nanofils de palladium ou des nanofils de polymères.

This research presents advancements in the coupling of capillary electrochromatography (CEC) to mass spectrometry (MS) for the analysis of different chemical classes of surfactants. Chapter 1 provides a brief introduction that summarizes the mechanics and fundamentals of CEC, including instrumentation and applications for CEC-MS. Chapter 2 describes the on-line hyphenation of a packed CEC column with an internally tapered tip coupled to electrospray ionization-mass spectrometry (ESI-MS) and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS) for the analysis of betaine-type amphoteric or zwitterionic surfactants (Zwittergent®). The interesting aspects include CEC-MS column manufacture and charaterization, as well as a comparison between the CEC-ACPI-MS and CEC-ESI-MS ionization pattern of zwittergents. In Chapter 3, the CEC-MS of alkyltrimethyl-ammonium ions (ATMA+) with chain length ranging from C1-C18 is optimized using an internally tapered CEC-MS column packed with mixed mode C6/strong cation exchange stationary phase and coupled to an ESI source. In addition, the optimized CEC-ESI-MS protocol is applied for the challenging analysis of commercial sample Arquad S-50 ATMA+ containing cis-trans unsaturated and saturated soyabean fatty acid derivatives. In Chapter 4, a novel CEC-UV method for separation of the various Triton X-100 oligomers is presented. A systematic mobile phase tuning and comparison of monomeric vs. polymeric stationary phases was conducted. In Chapter 5, we present the first application of CEC coupled to MS for analysis of Triton X (TX-) series surfactants. A characterization from the viewpoint of the ion and adduct formation for TX-series nonionic surfactants with a variable number of ethoxy units (n=1.5-16) in the scan mode are first discussed. Next, utilizing the TX-series as model alkylphenolpolyethoxylates (APEOs), a detailed investigation of the chromatographic separation and MS detection are performed followed by analysis of very long chain TX series with n=30-70. In Chapter 6, CEC-MS utilizing full scan positive ion mode of ESI was employed to study the effect of fragmentor voltage on the in-source collision induced dissociation (IS-CID) of several APEO nonionic surfactants. Finally, in Chapter 7, the preparation and characterization of a novel liquid crystalline stationary phase suitable for separation of neutral and charged compounds in packed column CEC is evaluated.

The transport of components and phases plays a fundamental role in the success of an EOR process. Because many reservoirs have harsh conditions of salinity, temperature and rock heterogeneity, which limit process options, a robust system with flexibility is required. Systematic experimental study of formulations capable to transport surfactant as foam at 94°C, formulated in sea water, is presented. It includes methodology to conduct core floods in sand packs using foaming surfactants and to develop “surfactant blend ratio- salinity ratio maps” using equilibrium phase behavior to determine favorable conditions for oil recovery in such floods. Mathematical model able to reproduce the foam strength behavior observed in sand packs with the formulations studied is presented. Visualization of oil recovery mechanism from matrix is realized using a model system of micro-channels surrounded by glass beads to mimic matrix and fractures respectively. The observations illustrate how components may distribute within the matrix, thereby releasing oil into the fractures. The use of chemicals to minimize adsorption is required when surfactant adsorption is important. The presence of anhydrite may limit the use of sodium carbonate to reduce adsorption of carbonates. A methodology is presented to estimate the amount, if any, of anhydrite present in the reservoir. The method is based on brine software analysis of produced water compositions and inductively coupled plasma (ICP) analysis of core samples. X-ray powder diffraction (XRD) was used to verify the mineralogy of the rock. X-ray photoelectron spectroscopy (XPS) was used to obtain surface composition for comparison with bulk composition of the rock. Adsorption of surfactants was measured using dynamic and static adsorption experiments. Determining the flow properties of the rock samples via tracer analysis permitted the simulation of the dynamic adsorption process using a mathematical model that considers the distribution of adsorbed materials in the three different regions of pore space. Using this method allows one to predict adsorption in a reservoir via simulation.

<p>Coatings for exterior wood have two basic functions. One isto give an aesthetically acceptable surface appearance andcolour. The other is to provide protection against wooddegradation by microbiological or physical attack. Theseprotective properties, often called the barrier properties,play an important role in the selection of proper material forsupreme durability. The assessment of these barrier propertiesis of great importance. Within the CEN Technical Committee 139,Working Group 2, Coatings for exterior wood test methods andperformance specifications have been established. Forassessment of water protection efficiency a standard testprocedure, EN 927-5, has been launched. The present work hasfocused on its applicability in assessing water protectionefficiency in relation to the degradation of coatings duringexposure.</p><p>Assessments according to EN 927-5 is shown to givesignificant differences in water absorption values fordifferent types of coatings on wood. The proposed performancespecifications in ENV 927 - 2 for the water absorption valuesfor coatings to be used in different constructions seem to beset at acceptable levels. It has been shown that there is agood correlation between the level of water absorption andpractical experience of the performance of paints inScandinavia. However, it has also been shown that thecombination of a standard procedure for water absorptionmeasurement and an artificial weathering procedure gives moreinformation regarding expected durability and longtermperformance than a single measurement of water absorption onfresh, unweathered coated wood. A combination of waterabsorption measurement and artificial weathering could become auseful tool in product development as well as in benchmarking.Together with statistical tools, such as reliability-basedservice life prediction methodologies for predicting theservice life of coating systems a reduction in testing timesmay be achieved.</p><p>Surface-active substances in coatings have a negative effecton the coatings ability to prevent water ingress, which mostprobably is due to the hydrophilic character of thesesubstances. The presence of these substances, which are commonin waterborne coatings, alters the moisture sorptioncharacteristics of wood. Considering that these substancesoccur in waterborne coatings, may be mobilised during and afterfilm formation and accumulate at the coating/substrateinterface, there is a great probability that these substanceschange the moisture sorption characteristics of the woodsubstrate in an unfavourable way and create unexpected dynamicmoisture conditions at the coating/wood interface.</p><p>Computerized tomography has been found to be a valuable,non-destructive tool for visualising the spatial moisturedistribution of water and moisture in coated wood panels. Themethod is suitable for recurrent testing of a specimen exposedto a series of processes of wetting, drying. This thesis showsthat high moisture contents occur locally at and around cracks.In these areas there is an increased risk of internal tensionand stress resulting in crack initiation and propagation andthat high moisture contents may occur in the first fewmillimetres under waterborne coatings despite intact coatingfilms. Even with good barrier properties of the coating,moisture may accumulate by water-vapour absorption in air gapsbehind the cladding thus causing favourable conditions formicrobiological colonization.</p><p>The work that has been carried out regarding assessment ofthe water protection efficiency shows promising resultsregarding the possibility to use reliability-based service lifeprediction methodology for the assessment. The aim of futurework will be to establish more reliable techniques andprotocols for assessing service life expectancy and durability,especially for waterborne coatings with special focus ontendencies to early failure and robustness of the coatingsystems.</p><p><b>Keywords:</b>Coatings, surfactants, water absorption value,EN 927, paint, additives, moisture dynamics, absorption,desorption, artificial weathering, artificial exposure,computerized tomography, MRI.</p>

<p>Surfactants are molecules that contain a water-soluble and afat-soluble part. They have important functions in productssuch as detergents, cosmetics, pharmaceuticals and foods aswell as in many industrial processes. Surfactants are used onvery large scale, which makes it important to decrease theirimpact on the environment. This can be done by starting withnatural materials, by improving the synthetic methods and byreducing the use of limited resources such as energy andorganic solvents.</p><p>This thesis focuses on lipase-catalyzed synthesis ofsurfactants based on natural products. It also includesfunctional studies of the produced surfactants; as antioxidantsin oils, or as surfactants to solubilize pharmaceuticals.</p><p>Unsaturated fatty acid esters of ascorbic acid weresynthesized with catalysis by Candida antarctica lipase B in<i>t</i>-amyl alcohol and in ionic liquids. High yields ofascorbyl oleate were obtained in an ionic liquid that wasdesigned to improve the solubility of the fatty acid, when thereaction was performed under vacuum. Ascorbyl oleate wasamorphous and was a better antioxidant than ascorbyl palmitatein rapeseed oil.</p><p>Polyethylene glycol (PEG) stearate, PEG 12-hydroxystearateand a series of PEG 12-acyloxy-stearates were synthesized in avacuum-driven, solvent-free system using<i>C. antarctica</i>lipase B as catalyst. Critical micelleconcentration and solubilization capacity were determined forthe PEG 12-acyloxy-stearates. Their effects on living cellswere evaluated in studies of hemolysis and transepithelialelectrical resistance. Several PEG1500 12-acyloxy-stearateswere excellent solubilizers for pharmaceutical use and hadnegligible negative effects on living cells even at highconcentrations.</p><p>Enzymatic and chemo-enzymatic methods offer uniquepossibilities to synthesize surfactants of high purity. Pureand well-defined surfactants enable new applications and areimportant for the understanding of surfactantstructure-function relationships.</p>

Dissociation of gas hydrates has been the primary concern of the oil and gas industry for flow assurance, mainly in an offshore environment. There is also a growing interest in the rapid formation of gas hydrates for gas storage, transport of natural gas and carbon sequestration. In this thesis, we experimentally measure the kinetics of formation and dissociation of methane hydrates and the effect of various anionic and cationic surfactants such as sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and alpha olefin sulfonate (AOS) on the association/dissociation rate constants. The importance and necessity of micelle formation in these surfactants has been studied. The effect of foam generation on the rate of formation of these hydrates has also been measured. SDS was found to significantly decrease the induction time for hydrate formation. There was an added decrease in the induction time when a foamed mixture of water and SDS was used. On the other hand CTAB and AOS had an inhibiting effect. The contribution of micelles towards promoting hydrate formation was demonstrated with a series of experiments using SDS. The micelles formed by these surfactants appear to serve as nucleation sites for the association of hydrates. New experimental data is presented to show that some surfactants and the use of foam can significantly increase the rate of hydrate formation. Other surfactants are shown to act as inhibitors. A new experimental setup is presented that allows us to distinguish between surfactants that act as promoters and inhibitors for hydrate formation. / text

This thesis concerns studies of aqueous soft matter systems, especially surfactant micelle systems. The aim has been to study the molecular arrangement and electronic structure of the constituents of, as well as transport properties in such a system. The molecular arrangement and electronic structure has been studied by means of X-ray absorption spectroscopy (XAS) and resonant inelastic X-ray spectroscopy (RIXS). The transport properties have been investigated by low-frequency dielectric spectroscopy (LFDS) and small angle X-ray scattering (SAXS) as well as a theoretical modelling. The latter was based on Fick’s laws of the release from binary surfactant system and was validated by experiments. The RIXS and XAS measurements show the electronic structure in bulk water and the influence of the chemical surrounding of the water molecule in bulk water and of the water molecules confined in a micelle lattice. The spectra are highly dependent on the molecular arrangement in such systems. For glycine and sodium polyacrylate RIXS and XAS spectra show features which are unique for carboxyl and carboxylate groups and such measurements can thus be used for fingerprinting. The LFDS and SAXS measurements show a strong correlation between structure in a surfactant/poly-ion system and apparent mobility of surfactants. This conclusion is in line with earlier observations. By the theoretical modelling a predictive model for the surfactant release from a binary surfactant micelle system has been obtained and the importance of different factors for surfactant release has been further clarified.