<div><div><div><p>Interfacial rheology describes the functional relationship between the deformation of an interface, the stresses exerted in and on it, and the resulting flows in the adjacent fluid phases. These interfacial properties are purported to influence emulsion stability. Protein emulsifiers tend to adsorb to the interface of immiscible phases, reduce interfacial tension as well as generate repulsive interactions. A magnetic interfacial shear rheometer was used to characterize the surface pressure-area isotherms as well as interfacial rheological properties of two proteins- sodium caseinate and b-lactoglobulin. Then, sodium caseinate was used as a carrier for b-carotene encapsulation.</p><p>b-carotene is a carotenoid that exhibits pro-vitamin A activity, antioxidant capacity and is widely used as a food colorant. It is however, highly hydrophobic and sensitive to heat, oxygen and light exposure. Thus b-carotene as food ingredient is mainly available as purified crystals or as oil-in-water emulsions. In this study, b-carotene stability, and solubility in water for application as a natural colorant was improved by preparation of a sodium caseinate/ b-carotene powder using high pressure homogenization, solvent evaporation and spray drying. The powders thus prepared showed good solubility in water and yielded an orange coloration from b-carotene. The effect of medium chain triglyceride concentration (1%, 10%) and incorporation of a natural antioxidant (Duralox, Kalsec) on powder stability was studied as a function of storage time and temperature.b-carotene stability was reduced at higher storage temperature (4oC> 21oC> 50oC) over 60 days and followed first order degradation kinetics at all temperatures. Incorporation of natural antioxidant improved b-carotene stability and resulted in a second first order degradation period at 50oC. As b-carotene content decreased, Hunter Lab color values denoting lightness increased, while those for redness and yellowness of the powder decreased. This sodium caseinate based b-carotene powder could be used as a food ingredient to deliver natural b-carotene to primarily aqueous food formulations.</p><div><div><div><p>In the last part of this work, an engagement workshop was developed as a means to educate young consumers about the function of emulsifiers in foods. Food additives are important for food product development, however to consumers, a discord between their objective purpose and subjective quality has led to confusion. Food emulsifiers, in particular, are associated with lower healthiness perception due to their unfamiliar names. In collaboration with the 4H Academy at Purdue, a workshop high school student was conducted to develop an increased understanding of emulsions and emulsifiers. A survey was conducted with the participants who self-evaluated their gain in knowledge and tendency to perform certain behaviors with regards to food ingredient labels. The participants reported a gain in knowledge in response to four key questions on emulsions and emulsifiers, as well as an increased likelihood to read ingredients on a food label and look up information on unfamiliar ingredients.</p></div></div></div></div></div></div>

Este trabalho descreve um método para expandir a aplicabilidade do sistema FreeFlow-2D para problemas de escoamentos de fluidos multifásicos. Este método permite a simulação de escoamento de fluido multifásico, incompressível e com superfície livre. Um número arbitrário de fases com propriedades diferentes pode ser utilizado. Tensões superficial e interfacial são também consideradas. A técnica numérica utilizada baseia-se no GENSMAC (Generalized-Simplified-Marker-and-Cell) e consideram-se propriedades variáveis de acordo com a posição da interface durante o escoamento. O campo de velocidade é computado utilizando-se às equações de Navier-Stokes discretizadas por esquema de diferença finita numa malha deslocada. O método foi implementado em três módulos: Modelador, Simulador e Visualizador. A validação foi efetuada comparando-se os resultados numéricos com resultados analíticos e experimentais. O método mostrou-se robusto e computacionalmente eficiente para os problemas considerados. / This work describes a method to expand the applicability of the system FreeFlow-2D in multi-phase flows problems. This method allows the simulation of incompressible free surface multi-phase flows. An arbitrary number of phases having different properties can be used. Surface and interface tension effects are also considered. The numerical technique is based on the GENSMAC (Generalized-Simplified-Marker-and-Cell) and it considers the properties varying according to the position of the interfaces in the flow. The velocity field is computed using the Navier-Stokes equations discretized by finite-difference on stagered grid. The method was implemented in three modules: the modeling module, the simulation module, and the visualization module. The validation was effected by comparing numerical results with analytical and experimental results. The method shown to be robust and computationally efficient in the problems considered.

Neste trabalho enfoca-se o efeito da variação térmica na degradação da aderência de revestimentos de argamassa. Dentre os diversos fatores que condicionam a aderência dos revestimentos de argamassa, destaca-se aqui o cenário crítico definido pela presença de macrodefeitos na interface revestimento-base e também pela intensidade com que ocorre a variação de temperatura, encontrando-se uma situação extrema quando da ocorrência do choque térmico. Assim, o objetivo desta pesquisa é avaliar, de maneira experimental, o efeito de sucessivos ciclos de choque térmico na resistência de aderência de revestimentos de argamassa, em duas situações limites de taxa de macro-defeitos no contato entre o revestimento e a base e para duas distintas argamassas. Para dar suporte ao trabalho experimental foi elaborado um modelo computacional paramétrico, utilizando modelagem com elementos finitos. Com ele foi possível obter a distribuição de temperaturas, bem como as deformações e tensões geradas no revestimento, variando-se a intensidade do contato revestimento-base e alterandose as características da argamassa de revestimento. A partir de então, definiram-se as variáveis de maior influência e a geometria dos corpos prova, bem como as condições de contorno a serem utilizadas no programa experimental. O programa experimental foi desenvolvido em duas etapas: uma etapa piloto e outra definitiva. Para sua realização foram desenvolvidos e construídos os equipamentos para execução e controle dos ensaios cíclicos de choque térmico. Finalmente, foram realizados ensaios de resistência de aderência do revestimento e avaliados os efeitos de cada uma das variáveis estudadas, empregando-se suporte estatístico. Pelos resultados pode-se comprovar que os macro-defeitos na interface revestimento-base provocam diminuição na resistência de aderência a qual é agravada quando da ocorrência de cíclicos choques térmicos, ocorrendo a situação mais crítica para os revestimentos com maior módulo de elasticidade. / The present study focus on thermal variation effects on mortar rendering bonding degradation. Among the variety of factors that condition the bonding of mortar renderings, a critic scenario can be defined by the existence of interface macro-flaws between mortar rendering and substrate, and by the thermal variation intensity in the extreme situation of thermal shock. This research aims to experimentally evaluate the effects of continuous thermal shock cycles on the bonding strength of mortar renderings in two macro-flaw rate extreme situations in the contact surface between mortar rendering and substrate for two types of mortar. A parametric model based on finite element analysis has been developed to support the experimental work, which allowed ascertaining temperature profile as well as stress and strain distribution in the mortar rendering by changing the macro-flaws rate and mortar rendering properties. As a result, one could define the variables with higher influence and test panel geometry, as well as the boundary conditions to be used in the experimental program. The experimental program has been performed first in pilot scale and then in a definite stage, which required designing and building of equipment for the execution and control of cyclic thermal shock laboratory tests. Furthermore, bond strength tests have been performed on the mortar rendering samples, and effects of variables have been analyzed by using statistical help. Results have shown that the existence of interfacial macro-flaws decreases bond strength values between mortar rendering and substrate, and this scenario worsens under thermal shock. Mortar renderings with higher Youngs modulus (E) are more affected.

<div>The House Cricket (Acheta domesticus) is a promising alternative to traditional protein sources, as these insects produce over 12 times the mass of protein for a given mass of food/water when compared to cattle, while also producing lower amounts of greenhouse gases and NH3 emissions (Kim et al. 2017, Hanboonsong, Jamjanya and Durst 2013, Van Huis 2013). Additionally, previous studies have demonstrated significant emulsification and gelling properties of insect flours, such as from cricket, which has been attributed to the functional properties of the protein (Kim et al. 2017). Ground cricket flours contain significant quantities of both protein and fibrous polysaccharides, particularly chitin. Since chitin particles are also capable of preparing emulsions as a Pickering stabilizer, there remains a question on the relative role of the protein and chitin components in crickets for stabilizing emulsion products. Relative contributions of each component was identified by first isolating the water-soluble protein and water-insoluble chitin fractions from ground cricket flour and then determining their interfacial properties and stability of prepared oil-in-water emulsions. Dynamic interfacial tension measurements indicated significant surface activity of the protein fraction, while there was minimal evidence of significant surface pressure development in the presence of 5-10 μm chitin particles. 10 % (w/w) canola oil-in-water emulsions were prepared with 0.5-2% (w/w) of the water-soluble protein fraction and 5.29% (w/w) canola oil-in-water emulsions were prepared with 0.688% of the chitin fraction. Stability of the emulsions against creaming was between 75% and 90% for emulsions stabilized by the protein fraction over three weeks of storage and between 93% and 96% for emulsions stabilized by chitin over 24 hours of storage. Significant fractions of precipitate- and oil-layers found in chitin-stabilized dispersions was attributed to the presence of large chitin particles (79 μm volume weighted mean diameter) and inefficient adsorption to droplet interfaces during homogenization, respectively. Volume-weighted mean diameter of emulsified oil droplets remained at 17-24 μm among protein-stabilized (>1.5 wt%) emulsions over three weeks of storage but only 60 μm over 24 hours among chitin-stabilized emulsions. Light micrographs of emulsion droplets showed successful adsorption of chitin fractions to oil droplets in the emulsion layer, verifying their potential as Pickering stabilizers. These findings demonstrated that both water-soluble protein and chitin particles obtained from ground cricket flours are legitimate emulsion stabilizers, yet the chitin fraction is much less effective without a more intensive approach to reduce their particle size.</div>

O processo de absorção do CO2 em soluções aquosas de alcanolaminas foi estudado em uma coluna de parede molhada empregando-se uma tela metálica, de 28 mesh, como promotor de película e operando em contracorrente. As alcanolaminas testadas nos diferentes experimentos foram: monoetanolamina (MEA), 2-amino-2-metil-1-propanol (AMP) e piperazina (PZ). Os experimentos de absorção foram realizados nas soluções aquosas individuais da MEA e AMP; e, nas misturas MEA:AMP e AMP:PZ; visando avaliar a velocidade de absorção do CO2 em diferentes vazões do líquido, a saber: 3.10-7, 6.10-7 e 10.10-7 m3/s. O presente sistema de absorção foi caracterizado através da determinação dos principais parâmetros de transferência de massa: área interfacial efetiva, coeficiente de transferência individual da fase gasosa e o coeficiente volumétrico global médio de transferência de massa. Determinou-se a área interfacial efetiva da coluna, por meio da absorção do CO2 diluído em ar em uma solução aquosa de NaOH, para as diferentes vazões de líquido, sendo os resultados obtidos igual a 106, 126 e 144 m2/m3, respectivamente. O coeficiente volumétrico de transferência de massa da fase gasosa foi determinado por meio da absorção de SO2 diluído em ar em uma solução aquosa de NaOH. Os resultados experimentais mostram que o coeficiente volumétrico individual de transferência de massa e a área interfacial são função da vazão do líquido. As velocidades de absorção do CO2 diluído em ar, em soluções de aminas e suas misturas foram determinadas experimentalmente para diferentes vazões de líquido, sendo os resultados expressos na forma de coeficientes globais de transferência de massa e parâmetros cinético-difusivos da fase líquida. As velocidades de absorção em MEA são bem superiores aos de AMP e NaOH. No caso das misturas foram obtidas velocidades superiores em comparação às das aminas individuais. A velocidade de absorção em AMP é fortemente incrementada na presença de PZ, mesmo em baixa concentração. / The CO2 absorption process in alkanolamine aqueous solutions was studied in a wetted wall column employing a film promotor of thin stainless steel woven wire, 28 mesh, which was operated in countercurrent. The tested alkanolamines were monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). The absorption experiments were performed in individual aqueous solutions of MEA and AMP and the mixtures MEA:AMP and AMP:PZ, with the aim of evaluating the CO2 absorption rate in different liquid flow rates, namely: 3.10-7, 6.10-7 e 10.10-7 m3/s. This absorption system was characterized through determining of the main parameters of mass transfer: effective interfacial area, individual mass transfer coefficient of the gas phase and the average overall mass transfer volumetric coefficient. The effective interfacial area was determined by the absorption of CO2 diluted in air into an aqueous solution of NaOH for the different liquid flow rates, and the results obtained are 106, 126 and 144 m2/m3, respectively. The mass transfer volumetric coefficient of the gas phase was determined by chemical method of the absorption of SO2 diluted in air into an aqueous solution of NaOH. The experimental results show that the individual mass transfer coefficient and interfacial area are a function of liquid flow rate. On the other hand, the results of the performance of CO2 absorption into amine aqueous solutions were expressed in function of the average overall mass transfer volumetric coefficient and liquid phase diffusive kinetic parameters, which were measured experimentally for different liquid flow rates. The absorption rate in MEA are higher in comparison with AMP and NaOH. In the case of the blended, the absorption rate in AMP is enhanced by piperazine, even in low concentration.

Investigate the interaction of nanomaterials with biological systems, known as nano-bio interaction is of great interest for the assessment of the concern arising from nanomaterials progressive use. Such interaction determines nanomaterials potential effect on human and environment becomes more and more important to understand how they interact with living organisms and the environment. The novel physicochemical characteristics of nanomaterials, such as their small size, large surface area to volume ratio and surface energy, may initiate new toxicological effects due to nanomaterials ability to enter into the biological systems through adsorption and dissolution and modify the structure of various macromolecules An example of these interactions is the adsorption of proteins on nanoparticles surface forming what is known as the 'protein corona'. Therefore, being able to understand how these molecules and other biologically important species are adsorbed and interact, should help us to reduce any adverse impacts of nanoparticles on human health and the environment. Due to the importance of surface composition and surface functionality in nanotoxicology, analytical tools that can probe the change in the structure and composition of the nanoparticles in aqueous media are crucial but remain limited. Therefore in this work, in situ characterization of the liquid–solid interface to probe surface adsorption of environmentally and biologically relevant media on nanoparticle surfaces has been conducted. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy provides the molecular information that allows for the determination of the adsorption mode such as conformational and structural changes of the coordinating ligand. Surface adsorption of titanium dioxide (TiO2) nanoparticles have been investigated in different biological media typically used for toxicity studies and show that the surface composition of TiO2 nanoparticles depends to a large extent on the composition of the medium due to surface adsorption. Moreover, hydrodynamic diameter and surface charge of TiO2 NPs were evaluated using dynamic light scattering DLS. The results indicated that TiO2 NPs undergo different trends in aggregation upon the adsorption of biological media on its surface and zeta potential measurements showed surface charge alterations which are consistent with the aggregation study. In order to understand the dynamic transformations of nanomaterials in biological environments, the effect of dissolution has been predicted. Copper oxide CuO and zinc oxide ZnO nanoparticles were used to study dissolution due to their instability in biological media. Once these particles exposed to solutions they release their ions and tend to aggregate. Therefore, the dissolution of these materials was conducted at size ca. 24 nm and nanoparticles coated with proteins and humic acid employing simulated lung fluids as models to develop a better understanding of how these properties effect the solubility and stability in biological systems. From this study, it was found that both copper oxide and zinc oxide NPs showed different trends in dissolution. Cu and Zn ions once coated with proteins and HA highly dissolved in ALF at low pH 4.5 compared with other fluids (Gamble’s solution and water) at extracellular pH which shows only slightly enhanced in the basal condition. The acidity of ALF may explain the higher solubility of metals that are phagocytized versus those that remain extracellular. Some general conclusions can be drawn from these investigations. It seems that analytical tools to characterize the interfacial region between nanopaerticles and these complex systems provide a reasonably good qualitative and quantitative description of the interactions.

Reactions of aqueous Fe(II) with Fe and Mn oxides influence heavy metal mobility, transformation of trace organics, and important elemental cycles as Fe precipitates form or dissolve, and as electrons move between aqueous and solid phases. Our objective was to characterize reactions of Fe(II) with important metal oxides, using a suite of complementary tools to investigate the extent and underlying mechanisms of Fe(II)-metal oxide redox activity. Nanoscale materials (1-100 nm) may have fundamentally different surface or electronic properties than larger solids. Goethite was synthesized with primary particle dimensions above or below the nanoscale. Despite large differences in particle surface area, goethite nanorods and microrods had similar net Fe(II) sorption and electron transfer properties. Experimental evidence suggested particle aggregation resulted in particle complexes of a similar size, meaning considerations of available reactive surface area could explain our results. Kinetics and extent of Fe(II)-Fe(III) redox reactions between aqueous Fe(II) and goethite were examined using a stable isotope tracer approach. Aqueous Fe(II) that had been enriched in 57Fe was mixed with isotopically-normal goethite. Convergence of Fe isotope ratios in aqueous and solid phases to values predicted by complete Fe atom exchange provided evidence that all goethite Fe(III) atoms could eventually react with Fe(II), despite no evidence for complete atom exchange from bulk measurements of the aqueous or solid phase. Fe isotope data at different experimental conditions was combined with theoretical considerations governing electron transfer in goethite to provide evidence for redox-driven atom exchange involving bulk conduction of electrons between spatially distinct Fe(II) sorption and release sites. Procedures for stable Fe isotope tracer studies have been adapted to investigate redox transformations of magnetite solids with different divalent cation content. Evolution of aqueous Fe(II)-Mn(IV) redox reactions was examined using complementary techniques. After pyrolusite particles were exposed to aqueous Fe(II), aqueous Fe and Mn were analyzed, and X-ray diffraction was utilized with electron microscopy to assess solid phase evolution during continued exposure to Fe(II). Selective use of Fe isotopes during Fe(II) resuspensions allowed us to track chemical changes occurring to one particular Fe addition using 57Fe Mössbauer spectroscopy.

As carbon dissolution rates have been determined for a few chars only, a systematic and comprehensive study was undertaken in this project on the dissolution behaviour of carbon from non-graphitic materials into liquid iron. In addition to measuring the kinetics of carbon dissolution from a number of coal chars into liquid iron as a function of parent coal and coal ash composition, the influence of chemical reactions between solute/solid carbon and ash oxides was also investigated. These studies were supplemented with investigations on one metallurgical coke for the sake of comparison. The wettability of coal chars and coke with liquid iron at 1550 degrees C was measured as a function of time. Being essentially non-wetting, only a marginal improvement in contact angles was observed with time. The accumulation of alumina at the interface was detected for all materials and was seen to increase with time in all cases. Calcium and sulphur also appeared to preferentially accumulate at the interface, concentrating at levels in excess of those expected from the ash composition alone. Despite the high levels of silica in the ash initially, very little silica was detected in the interfacial region, implying ongoing silica reduction reactions. A small amount of silicon was however detected in the iron droplets, indicating silica reduction with solute carbon. It was identified that the reduction reactions can also consume solute carbon in the liquid iron. As this is occurring simultaneously with carbon dissolution into liquid iron, the interdependency of silica reduction and carbon dissolution could potentially limit the observed carbon dissolution rate. A theoretical model was developed for estimating the interfacial contact area between chars and liquid iron. Wettability was found to have a very significant effect on the area of contact. A two-step behaviour was observed in the carbon dissolution of two chars and coke. Slow rates of carbon dissolution in stage II were attributed to very high levels of interfacial blockage by reaction products leading to much reduced areas of contact between carbonaceous material and liquid iron. The first order dissolution rate constants for four chars/coke and the observed trend in first order dissolution rate constants were calculated. These dissolution results compare well with the previously measured dissolution rate constants. The trends in dissolution can be adequately explained on the basis of carbon structure, silica reduction, sulphur concentration in the metal and ash impurities.

Copolymers are used to increase the interfacial strength of immiscible components and suppress recombination of the minor phase by steric hindrance. The experiments conducted in these studies are designed to investigate in situ polymer loop formation at soft interfaces and functionalized nanotube surfaces. Block copolymers are the most effective type of copolymer for compatibilization because they extend perpendicular to the interface, allowing good entanglement with the homopolymer chains. Multiblock copolymers are more effective than diblock copolymers for strengthening the interface because they can cross the interface multiple times, forming “loops” in each phase that provide entanglement points for the homopolymer. The first part of this dissertation focuses on understanding how telechelic variables influence their effectiveness to compatibilize an immiscible polystyrene (PS)/polyisoprene (PI) homopolymer blend. A fast reacting anhydride and amine telechelic pair (Anh-PS-Anh/NH2-PI-NH2) are compared with a slower reacting epoxy and carboxylic acid pair (Epoxy-PS-Epoxy/COOH-PI-COOH). Different molecular weight pairs are used to investigate the influence of end group concentrations and steric effects. We also investigate how the loading level affects the conversion of one telechelic pair. The PI telechelic has a fluorescent tag, which enables gel permeation chromatography (GPC) with fluorescence detection to be used for determining the amount of tagged PI converted and the molecular weight of the copolymer formed in situ as a function of mixing time. The effectiveness of these telechelic pairs as compatibilizers is quantified by annealing the samples and using scanning electron microscopy (SEM) to measure the domain size of the minor phase as a function of annealing time. The second part of this study investigates the grafting of polymer loops to carboxylated multiwall nanotube (COOH-MWNT) surfaces and determining the reaction rate. These polymer loops will improve the nanotube dispersion by steric hindrance and improve energy transfer by creation of polymer chain entanglements. Fourier transform infrared spectroscopy (FT-IR) is used as a novel technique to measure the quantity of Epoxy-PS-Epoxy grafted to the nanotube surface. In addition, we determined the fraction of telechelics that form loops by further reacting the grafted nanotubes with monocarboxy terminated poly(4-methylstryrene) (COOH-P4MS), which only reacts with unbound Epoxy-PS-Epoxy chain ends.

With the rise of nanotechnology in the last decade, nanofluidics has been established as a research field and gained increased interest in science and industry. Natural aqueous nanofluidic systems are very complex, there is often a predominance of liquid interfaces or the fluid contains charged or differently shaped colloids. The effects, promoted by these additives, are far from being completely understood and interesting questions arise with regards to the confinement of such complex fluidic systems. A systematic study of nanofluidic processes requires designing suitable experimental model nano – channels with required characteristics. The present work employed thin liquid films (TLFs) as experimental models. They have proven to be useful experimental tools because of their simple geometry, reproducible preparation, and controllable liquid interfaces. The thickness of the channels can be adjusted easily by the concentration of electrolyte in the film forming solution. This way, channel dimensions from 5 – 100 nm are possible, a high flexibility for an experimental system. TLFs have liquid IFs of different charge and properties and they offer the possibility to confine differently shaped ions and molecules to very small spaces, or to subject them to controlled forces. This makes the foam films a unique “device” available to obtain information about fluidic systems in nanometer dimensions. The main goal of this thesis was to study nanofluidic processes using TLFs as models, or tools, and to subtract information about natural systems plus deepen the understanding on physical chemical conditions. The presented work showed that foam films can be used as experimental models to understand the behavior of liquids in nano – sized confinement. In the first part of the thesis, we studied the process of thinning of thin liquid films stabilized with the non – ionic surfactant n – dodecyl – β – maltoside (β – C₁₂G₂) with primary interest in interfacial diffusion processes during the thinning process dependent on surfactant concentration 64. The surfactant concentration in the film forming solutions was varied at constant electrolyte (NaCl) concentration. The velocity of thinning was analyzed combining previously developed theoretical approaches. Qualitative information about the mobility of the surfactant molecules at the film surfaces was obtained. We found that above a certain limiting surfactant concentration the film surfaces were completely immobile and they behaved as non – deformable, which decelerated the thinning process. This follows the predictions for Reynolds flow of liquid between two non – deformable disks. In the second part of the thesis, we designed a TLF nanofluidic system containing rod – like multivalent ions and compared this system to films containing monovalent ions. We presented first results which recognized for the first time the existence of an additional attractive force in the foam films based on the electrostatic interaction between rod – like ions and oppositely charged surfaces. We may speculate that this is an ion bridging component of the disjoining pressure. The results show that for films prepared in presence of spermidine the transformation of the thicker CF to the thinnest NBF is more probable as films prepared with NaCl at similar conditions of electrostatic interaction. This effect is not a result of specific adsorption of any of the ions at the fluid surfaces and it does not lead to any changes in the equilibrium properties of the CF and NBF. Our hypothesis was proven using the trivalent ion Y3+ which does not show ion bridging. The experimental results are compared to theoretical predictions and a quantitative agreement on the system’s energy gain for the change from CF to NBF could be obtained. In the third part of the work, the behavior of nanoparticles in confinement was investigated with respect to their impact on the fluid flow velocity. The particles altered the flow velocity by an unexpected high amount, so that the resulting changes in the dynamic viscosity could not be explained by a realistic change of the fluid viscosity. Only aggregation, flocculation and plug formation can explain the experimental results. The particle systems in the presented thesis had a great impact on the film interfaces due to the stabilizer molecules present in the bulk solution. Finally, the location of the particles with respect to their lateral and vertical arrangement in the film was studied with advanced reflectivity and scattering methods. Neutron Reflectometry studies were performed to investigate the location of nanoparticles in the TLF perpendicular to the IF. For the first time, we study TLFs using grazing incidence small angle X – ray scattering (GISAXS), which is a technique sensitive to the lateral arrangement of particles in confined volumes. This work provides preliminary data on a lateral ordering of particles in the film. / Mit dem Heranwachsen der Nanotechnologie in den vergangenen zehn Jahren hat sich die Nanofluidik als Forschungsbereich etabliert und erfährt wachsende Aufmerksamkeit in der Wissenschaft, sowie auch in der Industrie. Im biomedizinischen Bereich, wo intrazelluläre Prozesse häufig komplexer, nanofluidischer Natur sind, wird sich vermehrt für ein detailliertes Verständnis von nanofluidischen Prozessen interessiert, z.B. für den Einfluss von Kolloiden verschiedenster Form oder elektrischer Ladung auf die Kanäle und auf das Fließverhalten oder die Auswirkungen der Einengung von Flüssigkeiten und Kolloiden in Nanometer Geometrien. In der vorliegenden Arbeit werden dünne flüssige Filme, hinsichtlich ihrer Funktion als nanofluidische Modelle untersucht. Im ersten Teil der Arbeit wurde die Fließgeschwindigkeit des Fluids aus dem dünnen Film, abhängig von der Konzentration der filmstabilisierenden Tensidmoleküle n – Dodecyl β – D – Maltoside ( β – C₁₂G₂) bei einer konstanten Elektrolytkonzentration von 0.2 mM NaCl untersucht. Mit einem theoretischen Modell konnte das Dünnungsverhalten nachgezeichnet werden. Es wurde eine kritische Tensidkonzentration gefunden, unter der die Oberflächen lateral mobil sind und über der sie sich wie fest verhalten. Dadurch konnten wir Aufschluss darüber erlangen, wie die Oberfläche des Films unter verschiedenen Bedingungen geschaffen ist, und das in Bezug zur Verteilungsdichte der Moleküle an den Oberflächen setzen. Im weiteren wurden komplexere, nanofluidische Systeme untersucht, wobei zum einen ~ 1 nm lange, stäbchenförmige, multivalent geladene Spermidin - Moleküle die punktförmigen Elektrolyte ersetzten. Es konnte eine deutliche Veränderung der Stabilität zwischen Filmen mit und ohne Stäbchen festgestellt werden. Die Filme, mit NaCl, blieben länger in dem metastabilen „Common Film“ (CF) Zustand als die Filme, die eine vergleichbare Konzentration von Spermidin Stäbchen beinhalteten. Die Ergebnisse deuteten auf eine zusätzliche Anziehungskraft durch Brückenbildung zwischen zwei geladenen Oberflächen durch gegensätzlich geladene Stäbchenförmige Moleküle hin. Es konnte gezeigt werden, dass dieser Effekt weder ein Ergebnis von spezifischer Ionenadsorption an die Filmoberfläche war, noch ein Unterschied in den Gleichgewichtszuständen von den Dicken der CFs und der Newton Black Films (NBFs) hervorrief, was auf die korrekte Annahme der Ionenstärke in der Lösung schließen ließ. Auch in Versuchen mit ebenfalls trivalenten Ionen YCl3 wurde festgestellt, dass kein vergleichbarer Überbrückungseffekt auftritt. Die Ergebnisse wurden mit theoretischen Simulationen verglichen und es wurde eine quantitative Übereinstimmung gefunden bezüglich der Größe des Systeminternen Energiegewinns durch den Überbrückungseffekt. Desweiteren wurde das Fließverhalten von Fluiden mit Kolloiden eingeengt in Nanometer Geometrien untersucht. Für zwei verschiedene Arten von Nanopartikeln (Fe3O4 stabilisiert mit Oleinsäure und polymerstabilisierte Goldpartikel) wurde eine Verlangsamung der Fließgeschwindigkeit festgestellt. Mit einem theoretischen Modell konnte das Fließverhalten nur für enorm erhöhte Viskositätswerte des Fluids erklärt werden. Die Viskositätserhöhung wurde mit Partikelaggregaten, die den Ausfluss behindern, erklärt und diskutiert, unter der Annahme eines nicht - Newtonischen Fließverhaltens der Dispersionen. Gleichermaßen wurde die strukturelle Anordnung der Partikel in den Filmen hinsichtlich ihrer vertikalen und lateralen Verteilung untersucht. In dieser Arbeit werden vorläufige Ergebnisse präsentiert, die noch weiteren Studien bedürfen. Mit Neutronenreflexion sollte die Anordnung der Partikel orthogonal zur Oberfläche im Film analysiert werden. Eine qualitative Analyse lässt schließen, dass bei einer höheren Konzentration von Partikeln in Lösung, sich auch eine erhöhte Konzentration von Partikeln im dünnen Film befindet. Leider konnten die Daten nicht hinsichtlich der Lage der Partikel analysiert werden. Zum ersten Mal wurden dünne flüssige Filme mit Kleinwinkelröntgenstreuung unter streifendem Einfall (GISAXS) analysiert. Mit Hilfe dieser Methode sollte eine laterale Anordnung der Partikel im Film untersucht werden. Es konnten erfolgreiche Messungen durchgeführt werden und mit Hilfe der rechnergestützten Analyse konnte eine Aussage gemacht werden, dass ~ 6 nm große Teilchen in ~ 43 nm Abstand sich im Film befinden. Die Aussage bezüglich der kleinen Teilchen könnte sich auf einzelne, kleinere Partikel beziehen, allerdings könnten auch die 43 nm eine relevante Strukturgröße darstellen, da es in der Dispersion gehäuft Aggregate mit dem Durchmesser in dem Größenbereich vorliegen. Zusammenfassend können sich mit dieser Arbeit die dünnen flüssigen Filme als eine wichtige Kernmethode der Untersuchung von nanofluidischen Prozessen, wie sie häufig in der Natur vorkommen, behaupten.