Relative to traditional methods, air-liquid interface (ALI) exposures constitute a superior in vitro model for assessing the toxicological activity of complex aerosols. By removing the medium barrier, aerosols can be delivered to the cells at their apical surface. This project investigated the utility of the commercially available VITROCELL® exposure system for comparative toxicological assessment of complex aerosols (freshly-generated diluted diesel exhaust and simulated urban smog). The system setup was modified to improve control of aerosol properties (temperature and humidity) and cellular responses (dynamic range). Following optimization, cytotoxicity (WST-1 and LDH assays) and expression of selected genes involved in proinflammatory signalling and oxidative stress responses (via quantitative RT-PCR) were quantified following 1 hour aerosol exposures. The results showed only limited, variable responses following exposures to high concentrations of diesel exhaust. Lack of consistent and robust responses are likely due to poor deposition of particulate matter from the test aerosols.

Ce travail de thèse est consacré à l’étude des déformations d’interfaces liquides par l’action d’une onde laser continue. Nous démontrons que la diffusion élastique d'une onde laser dans un milieu turbide induit une force diffusive en volume qui donne naissance à des écoulements permanents au sein du fluide. Les contraintes visqueuses associées à ces écoulements, à l’approche d’une interface liquide molle, peuvent engendrer la déformation de celle-ci jusqu’à la déstabiliser et former un jet. Dans ce manuscrit, nous présentons une étude expérimentale de ce nouveau couplage lumière-fluide complétée par des simulations numériques. Nous présentons également une étude des déformations et instabilité d'interfaces par la pression de radiation optique, due au contraste d’indice de réfraction entre les deux phases liquides en coexistence, dans des milieux transparents. Nous avons enfin analysé la combinaison de ces deux couplages dans les milieux turbides, force diffusive et pression de radiation participant différemment à la déformation d’interfaces liquides. Pour ce faire, nous avons eu recours à différents systèmes fluides turbides et transparents, ayant pour particularité principale de présenter une tension interfaciale extrêmement faible. / This thesis work is dedicated to liquid interface deformations from a continuous laser wave. We demonstrate that elastic scattering of the incident wave in turbid medium induces a scattering force density giving birth to permanent bulk flows in the fluid. Near a soft interface, viscous stresses associated to these flows can deform the interface up to instability and produce a liquid jet. In this manuscript, we report an experimental study dedicated to this new light-fluid coupling in combination with numerical simulations. We also study interface deformations and instability induced by radiation pressure, due to refractive index contrast between the two liquid phases in coexistence, in transparent fluids. We finally analyzed the combination of both couplings in turbid media, scattering force and radiation pressure which differently operate for the interface deformation. To do this, we used different turbid and transparent fluids systems, which have the main particularity to present very low interfacial tension.

Beim Stoffübergang einer grenzflächenaktiven Substanz in einem flüssigen Zweiphasensystem kann solutale Marangoni-Instabilität einsetzen. Die weitere nichtlineare Entwicklung der Marangoni-Instabilität geht mit einer enormen Vielfalt von Strömungsmustern einher. In der Literatur wird dieser Aspekt häufig unter dem unscharfen Ausdruck „Grenzflächenturbulenz“ zusammengefasst. Diese Arbeit stellt heraus, dass drei grundlegende Strukturformen existieren: Rollzellen, Relaxationsoszillationen und Relaxationsoszillationswellen. Ein großer Teil der Komplexität der Strömungsmuster ist dadurch begründet, dass die Grundstrukturen unterschiedliche Hierarchieebenen aufweisen. Es werden die zugrunde liegenden Bedingungen für das Auftreten der jeweiligen Strukturtypen, ihre transiente Natur und die Bildung der hierarchischen Strömungsmuster untersucht. Des Weiteren betrachtet diese Arbeit die Wechselwirkungen mit Dichteeffekten, die sowohl die Charakteristik der Strukturen als auch ihre zeitliche Entwicklung beeinflussen.

Die Effektivität der Reaktivextraktion als Verfahren zur Stoffabtrennung aus wässrigen Lösungen mit organischen Lösungsmitteln lässt sich durch den Zusatz weiterer Stoffe deutlich steigern. Das können Co-Ionen, Lösungsvermittler und Stoffe sein, die die Phasengrenzfläche beeinflussen. Wichtigste Vertreter der letzteren Gruppe sind Tenside, die die Grenzflächenspannung zwischen den Phasen verringern. Sie werden in der industriellen Technik bereits seit Jahrzehnten mit gleich bleibendem Erfolg angewandt. Dabei sind die Vorgänge an der Phasengrenze, die durch die Tenside beeinflusst werden, noch nicht vollständig geklärt. In diesem Umfeld ist auch die vorliegende Arbeit entstanden. Sie soll bereits am Lehrstuhl vorliegende Arbeiten ergänzen. Gegenstand der Untersuchungen ist der Einfluss von Tensiden auf die Extraktion von Schwermetallionen im elektrischen Feld, hier untersucht an dem kationischen Tensid Hexadecyltrimethylammoniumbromid (CTAB). Als Untersuchungsmethode wird die Polarographie verwendet. Der Ladungsdurchtritt durch die Grenzfläche Wasser/Quecksilber und deren Beeinflussung durch das Tensid werden für die Metallionen von Zink, Cadmium, Blei und Chrom bei unterschiedlichen pH-Werten untersucht. Es zeigt sich, dass die Modifizierung der Grenzfläche nur einen Teil der Beeinflussung ausmacht, weitere entstehen durch die chemische Modifizierung der vorhandenen Spezies. Weiterhin kann abgeleitet werden, dass trotz chemischer Verwandtschaft der eingesetzten Systeme eine klare Vorhersage der Beeinflussung nur begrenzt möglich ist. Der grundlegende Trend von Systemen mit chemisch ähnlicher Zusammensetzung ist zwar der gleiche, jedes System reagiert jedoch individuell in Abhängigkeit der genauen stofflichen Zusammensetzung und der Versuchsbedingungen, so dass stets konkrete Voruntersuchungen notwendig erscheinen.

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<p>Adsorption on solid surfaces from solution is a fundamental property of a surfactant. It might even be the most important aspect of surfactant behavior, since it influences many applications, such as cleaning, detergency, dispersion, separation, flotation, and lubrication. Consequently, fundamental investigations of surfactant adsorption are relevant to many areas.</p><p>The main aim of this thesis has been to elucidate the adsorption properties, primarily on the solid/water interface, of a particular class of polyhydroxyl based surfactants: the alkyl glucosides. By the use of ellipsometry, the equilibrium and kinetic aspects of adsorption on titanium dioxide with respect to structural effects has been studied. Furthermore, the effects of small amounts of cationic surfactant additives on the adsorption on silica have been investigated. The results have been compared with similar studies for other nonionic surfactants.</p><p>We have found that the surfactant structure has a strong effect on the adsorption properties. An increase in the surfactant chain length increases the cooperativity of the system. An increase in the head group polymerization decreases the cooperativity and the plateau adsorbed amount at equilibrium. The effect of surfactant structure on the adsorption kinetics depends on the concentration relative to the cmc, while the there is a decrease in the rate of desorption with increasing hydrophobic chain length independent of the concentration. The adsorption/desorption process is concluded to be diffusion driven, as suggested by the model used. When comparing these results with studies on ethylene oxide based surfactants, we conclude that the two types of surfactants exhibit similar trends on surfaces onto which they adsorb.</p><p>Adsorption from binary surfactant solutions is even more interesting than adsorption from single surfactant solutions, since it brings us one step closer to the systems used in applications. In addition, adsorption from a mixture can be very different from adsorption from any of the single surfactants in the mixture. Alkyl glucosides alone do not adsorb on silica, but addition of small amounts of a cationic surfactant to the alkyl glucoside solution allows for adsorption on silica. A comparison between the adsorption and bulk properties has shown that mixed micellization explains most, but not all, effects of the coadsorption properties. Changing the pH in the mixed systems reveals that a surfactant with a pH-dependent charge and the ability to adapt its charge to the environment, e.g. a surface, enhances the adsorbed amount over a wider range of pH values than a purely cationic surfactant.</p><p>It is well known that alkyl glucosides and ethylene oxides adsorb differently on different types of hydrophilic surfaces. As a consequence, replacing ethylene oxides with alkyl glucosides might not be all straight-forward; however, we have shown that the effect of the surface can be eliminated by the use of a cosurfactant.</p>

It is widely known that surfaces play an important role in numerous biological processes and technological applications. Thus, being able to modify surface properties provides an opportunity to control many phenomena occurring at interfaces. One way of controlling surface properties is to adsorb a polymer film onto the surface, for example through layer-by-layer (LbL) deposition of polyelectrolytes. This simple but versatile technique enables various polymers, proteins, colloidal particles etc. to be incorporated into the film, resulting in a multifunctional coating. Due to recent legislations and a consumer demand for more environmentally friendly products, we have chosen to use natural polymers (biopolymers) from renewable resources. The focus of this thesis has been on the adsorption of biopolymers and their layer-by-layer formation at solid-liquid interfaces; these processes have been studied by a wide range of techniques. The main method was the quartz crystal microbalance with dissipation monitoring (QCM-D), which measures the adsorbed mass, including trapped solvent and the viscoelastic properties of an adsorbed film. This technique was often complemented with an optical method, such as ellipsometry or dual polarization interferometry (DPI), which provided information about the “dry” polymer or protein adsorbed mass. From this combination, the solvent content and density of the layers was evaluated. In addition, the surface force apparatus (SFA), X-ray photoelectron spectroscopy (XPS), total internal reflection fluorescence (TIRF), and fluorescence resonance energy transfer (FRET) were utilized, providing further information about the film structure, chemical composition, and polymer inter-layer diffusion. Adsorption studies of the glycoprotein mucin, which has a key role in the mucousal function, showed that despite the net negative charge of mucin, it adsorbed on negatively charged substrates. The adsorbed layer was highly hydrated and the segment density on the substrate was low. We showed the importance of characterizing the mucin used, since differences in purity, such as the presence of albumin, gave rise to different adsorption behaviours in terms of both adsorbed amount and structure. The adsorbed mucin layer was to a large extent desorbed upon exposure to the anionic surfactant sodium dodecyl sulfate (SDS). In order to prevent desorption, we demonstrated that a protective layer of the cationic polysaccharide chitosan could be adsorbed onto the mucin layer and that the mucin-chitosan complexes resisted the desorption normally induced by association with SDS. Moreover, the association between chitosan and SDS was examined at the solid-liquid interface, in the bulk, and at the air-water interface. In all these environments chitosan-SDS complexes were formed and a net charge reversal of the complexes from positive to negative was observed when the concentration of SDS was increased. Furthermore, the LbL deposition method could be used to form a multilayer-like film by alternate adsorption of mucin and chitosan on silica substrates. The LbL technique was also applied to two proteins, lysozyme and β-casein with the aim of building a multilayer film consisting entirely of proteins. These proteins formed complexes at the solid-liquid interface, resulting in a proteinaceous layer, but the build-up was highly irregular with an increase in adsorbed amount per protein deposition cycle that was far less than a monolayer.Continuing with chitosan, known to have antibacterial properties we assembled multilayers with an anti-adhesive biopolymer, heparin, to evaluate the potential of this system as a coating for medical implants. Multilayers were assembled under various solution deposition conditions and the film structure and dynamics were studied in detail. The chitosan-heparin film was highly hydrated, in the range 60-80 wt-% depending on the deposition conditions. The adsorbed amount and thickness of the film increased exponential-like with the number of deposition steps, which was explained by inter-diffusion of chitosan molecules in the film during the build-up. In a novel approach, we used the distant dependent FRET technique to prove the inter-layer diffusion of fluorescent-labelled chitosan molecules within the film. The diffusion coefficient was insignificantly dependent on the deposition pH and ionic strength, and hence on the film structure. With the use of a pH sensitive dye buried under seven chitosan-heparin bilayers, we showed that the dye remained highly sensitive to the charge of the outermost layer. From complementary QCM-D data, we suggested that an increase in the energy dissipation does not necessarily indicate that the layer structure becomes less rigid. / Det är välkänt att ytor spelar en viktig roll i många biologiska processer och tekniska tillämpningar. Att kunna modifiera en ytas egenskaper ger därför en möjlighet att kunna kontrollera många fenomen som sker på ytor. Ett sätt att kontrollera ytegenskaperna är genom att adsorbera en polymerfilm på ytan, till exempel genom att växelvis adsorbera olika polyelektrolyter (LbL-teknik). Denna enkla men mångsidiga teknik möjliggör att många olika material kan införlivas i filmen, vilket resulterar i en multifunktionell beläggning. På grund av dagens lagstiftning och konsumenters ökade efterfrågan på miljövänliga material beslutade vi oss för att använda biologiska polymerer (biopolymerer) i detta projekt. Fokus i den här avhandlingen har varit på adsorption av biopolymerer och deras LbL-formation på gränsytan vätska-fast fas, där adsorptionsförloppet och det adsorberade skiktet bestående av biopolymerer studerats med en mängd olika tekniker. Huvudtekniken var kvartskristallmikrovåg med energidissipations-registrering (QCM-D), som mäter massan inklusive inkorporerat vatten, samt de viskoelastiska egenskaperna hos ett adsorberat skikt. Som komplement till denna teknik användes ofta optiska metoder, till exempel ellipsometri och ”dubbel polarisationsinterferometri (DPI)”, två tekniker som endast mäter massan av de adsorberade biopolymererna. Genom denna kombination av metoder kunde massan av inkorporerat vatten i filmen och filmens densitet bestämmas. Dessutom användes ytkraftsapparaten (SFA), röntgenfotoelektronspektrometri (XPS), och fluorescens-spektroskopiteknikerna TIRF och FRET i några undersökningar för att erhålla information om skiktens struktur, kemiska sammansättning och polymerernas diffusion inom skiktet.Adsorptionsstudier av glycoproteinet mucin, som har en central roll i funktionen av slemhinnan, avslöjade att trots att mucinet har en negativ nettoladdning adsorberade det ändå på negativt laddade substrat. Det adsorberade lagret var väldigt hydratiserat och hade en låg andel mucin i direkt kontakt med ytan. Vi påvisade vikten av att noga undersöka mucinet som användes, eftersom olika renhet, till exempel i form av förekomsten av albumin gav upphov till olika adsorptionsbeteende gällande både adsorberad mängd och struktur. En stor andel av det adsorberade mucinlagret desorberade när det exponerades för den anjoniska tensiden natriumdodecylsulfat, SDS. Vi visade att ett skyddande lager av den katjoniska polysackariden chitosan kunde adsorberas på mucinet och att mucin-chitosan-komplexen inte desorberade när SDS tillsattes. Därtill studerades växelverkan mellan chitosan och SDS på gränsytan vätska-fast fas, i bulken och på luft-vattengränsytan. Komplex av chitosan-SDS bildades i samtliga miljöer och en nettoladdningsomsvängning från positiv till negativ observerades när koncentrationen av SDS ökades.Vidare kunde LbL-tekniken nyttjas för att skapa ett multilagerlikt skikt genom att alternerande adsorbera mucin och chitosan på kiseldioxidsubstrat. Denna teknik användes även med två proteiner, lysozym och β-kasein, med målet att skapa ett multilager bestående av endast proteiner. Dessa proteiner bildade komplex på gränsytan vätska-fast fas i form av ett blandat proteinlager, men uppbyggnaden var väldigt oregelbunden med en ökning i adsorberad mängd per proteindeponeringscykel som var avsevärt mindre än ett monolager.Inom området för biomaterial utgör de antibakteriella och antihäftande egenskaperna hos chitosan respektive heparin en lovande blandning för beläggningar av medicinska implantat. Baserat på detta konstruerade vi multilagerfilmer av chitosan och heparin med olika deponeringslösningar och undersökte dynamiken och filmens struktur i detalj. Chitosan-heparin-filmen var starkt hydratiserad, bestående av cirka 60-80 vikt-% vatten beroende på deponeringsbetingelserna. Den adsorberade mängden och tjockleken på filmen ökade nästan exponentiellt med antal deponeringar, vilket förklarades med chitosanets förmåga att diffundera genom filmen under uppbyggnaden. Med ett nytt angreppssätt använde vi FRET för att bevisa diffusionen av fluorescerande färgmärkt chitosan i filmen under uppbyggnaden. Diffusionskoefficienten var i princip oberoende av pH och jonstyrka under deponeringen och följaktligen av filmens struktur. Genom att använda ett pH-känsligt färgämne begravt under sju biskikt av chitosan-heparin visade vi att färgämnet i hög grad påverkades av laddningen på det yttersta lagret. Från QCM-D-data lade vi fram teorin om att en ökning av energidissipationen för ett lager inte nödvändigtvis indikerar att lagrets struktur har blivit mindre styvt. / QC 20100729

Dans le cadre de la séparation sélective pour le traitement et la valorisation des combustibles nucléaires usés, l’extraction liquide/liquide est largement utilisée au niveau industriel. Néanmoins, ce procédé est encore mal compris en ce qui concerne les phénomènes physico-chimiques qui se produisent à l’interface liquide/liquide. Ce travail porte sur la compréhension de la dynamique de l’interface liquide nanométrique durant le transfert d’une espèce entre une phase aqueuse et une phase organique. Deux techniques expérimentales ont principalement été utilisées: la mesure de tension interfaciale et l’optique non linéaire. Ce travail a également donné lieu au développement d’un modèle numérique de dynamique de transfert de phase prenant en compte à la fois des phénomènes de transport diffusif proche de l’interface et une cinétique chimique sur l’interface décrivant les processus d’adsorption/désorption. Des systèmes modèles constitués de molécules surfactantes et/ou chromophores et/ou complexantes ont été étudiés aux interfaces air/liquide et liquide/liquide. L’adsorption/désorption, l’agrégation en surface, la complexation d’ion à une interface liquide et la structuration des systèmes ont ainsi pu être étudiées tant d’un point de vue des états d’équilibre que de la dynamique. Enfin, ces études ont été appliquées à un système d’intérêt industriel utilisé dans le procédé de dépollution DIAMEX / Liquid-liquid extraction processes are widely used in the industrial fields of selective separation. Despites its numerous applications, the microscopic mechanisms which occur during a liquid liquid extraction processes are really unknown specially at the liquid/liquid interface. Thus, this work deals on the understanding of the phenomena which drive the mass transfer across a liquid/liquid interface. Two experimental techniques were used in this work: dynamic interfacial tension measurement and non-linear optical experiments. Along with the use of this experimental approach, a numerical model describing the mass transfer dynamic has been developed. This model works under the assumption that both diffusion and a chemical step describing adsorption and desorption processes contribute to the global transfer kinetics. Model systems of surfactant molecules, chromophore molecules and complexing molecule were investigated at liquid/liquid and air/liquid interface. Interfacial phenomena like adsorption, surface aggregation and ion complexing were studied. Finally, the methodology developed in this work was applied to studied an extractant molecule with potential industrial application