Dans ce travail, les nanoparticles d’or supportées ont été étudiées en raison de leur fort potentiel dans les domaines de la catalyse. Des sphères de silice obtenues par la voie Stöber ont été synthétisées et utilisées comme supports des nanoparticules d’or. Les précurseurs d’or sont des solutions colloïdales possédant des nanoparticules d’or homogènes et de petite taille (environ 3 nm). Les matériaux préparés avec ou sans addition d’un nouvel élément ont été utilisés dans les réactions de l’oxydation du CO et une réaction inédite pour l’or: l’oxydation sélective de l’H2S.Les résultats indiquent que l’utilisation de colloïdes d’or comme précurseurs permet de contrôler la taille et la dispersion avant le dépôt et ceci est facilité par les propriétés optiques des nanoparticules de ce métal. Pour les propriétés catalytiques, outre la dispersion, on confirme très clairement par cette méthode de synthèse que l’interaction Au/Support joue un rôle majeur. L’addition d’un second métal augmente significativement l’activité des matériaux à base d’or. Les particules d’or et de Cu se rassemblent sous les conditions réactionnelles testées. Dans le cas de l’oxydation du CO, de petites quantités d’espèce d’or partiellement oxydée sont générées et forment une glue avec les espèces Cu2+ également formées au cours de la réaction et ceci permet de fixer les nanoparticules sur le support. Dans le cas de l’oxydation sélective de H2S, il a été montré que le système est résistant au soufre, y compris sur une longue durée de test. Les silices Stöber se sont avérées comme des supports catalytiques très intéressants car non poreux et formés de particules de petites tailles, ils sont aptes à exposer les phases actives de l’or aux réactifs, diminuant la pression de surface et facilitant le transfert thermique. Il a également été prouvé que ce matériau peut être mis en compétition avec les matériaux mésoporeux, ces derniers étant jugés indispensables pour obtenir de hautes activités en catalyse hétérogènes jusque là. / Supported gold nanoparticles have been focused on due to their high efficiency in the catalysis field. In this work, Stöber silica consisted by globules were synthesized and used as support for gold nanoparticles. The gold colloids with homogeneous and small nanoparticles (about 3 nm) were applied as gold precursor. The prepared materials with further metal addition were used to active the CO oxidation and another very special reaction- selective oxidation of H2S.The results suggested that by using the gold colloid as precursor the sizes of nanoparticles could be controlled before loading onto silica under the help of its optical properties. The results for catalytic reactions indicated that the interaction between Au-support is another essential factor impacting the activity beyond the size effect. The additions of metal largely enhance the activity of gold materials. The gold and copper (oxide) particles go through reassembling during the reactions. In the CO oxidation, small amounts of partially oxidized gold species were generated and “glued” strongly by the new formed Cu2+ species to the support. While in the selective H2S oxidation, it was found that the material is sulfur-resistant during long time reaction. The Stöber silica is proved to be a very promising support, which is non-porous but beneficial to expose active sites of gold nanoparticles to the reactants, lower the pressure drop, and facilitate the heat transformation. It was proved even can be matched with the well-know mesoporous materials that is claimed to be indispensable for the high activity.

A hemostasia é um evento biológico passível de ser avaliado e estudado, assim como seus distúrbios. Há situações durante a anestesia que podem cursar com alterações hemostáticas culminando com aumento do sangramento ou até mesmo hemorragias graves. Os tempos de coagulação têm recebido especial atenção tendo-se em vista os diferentes contratempos hemostáticos que pode ocorrer durante o procedimento anestésico-cirúrgico. Sendo assim, nesse estudo buscou-se estabelecer os valores padrões para tempo de protrombina (TP) e de tromboplastina parcial ativada (TTPA) para cães submetidos a diferentes procedimentos cirúrgicos. Foram estudados 50 cães hígidos para padronização dos valores de TTPA e TP utilizando aparelho automático. Os valores de TTPA estavam dentro dos valores de normalidade da literatura (6,9 a 17,6 segundos) e valores de TP discretamente maiores (de 6,65 a 12,8 segundos). Foram estudadas 20 cadelas classificadas como ASA I e 18 cães ASA II e III. Nestes animais observaram-se aumentos significativos de valores de TTPA (de 12,04 para 14,29 segundos em ASA I, com P<0,0378; e de 13,4 para 15,11 segundos nos cães ASA II e III, P<0,0067) e de TP (de 8,36 para 9,7 segundos em ASA I, P<0,0323; e de 8,32 para 9,34 segundos nos caes ASA II e III, P< 0,0084) entre os momentos pré e pós-anestésicos Estes aumentos acompanham quedas da pressão coloidosmótica, indicando que o processo de anestesia, cirurgia e fluidoterapia causam hemodiluição, e conseqüente aumento nos tempo de coagulação. / Hemostasis is a biological event that could be evaluated and studied, just like yours disturbs. There are situations in to anesthetic procedures that could curse with hemostatics disturbs causing bleeding increase or even critical blood loss. The blood clotting times have been received special attention because different hemostatic setbacks that could occur during the anesthetic and surgical procedures. This way, this study look for establish the values for reference to protrombine time (PT) and to activated partial tromboplastin time (APTT) for dogs. Were studied 50 healthy dogs to standardize the values of PT and APTT utilizing an automatic instrument. The APTT values was in agreement with the literature values (6,9 to 17, 6 seconds), and the PT values was discret increased when compared with literature (from 6,65 to 12,8 seconds). Was studied 20 bitches classifieds as ASA I and 18 dogs classifieds as ASA II and III. In this animals observed significant increase values of APTT (from 12,04 to 14,29 seconds in the ASA I, P<0,0378; and from 13,4 to 15,11 seconds in the dogs ASA II and III, P<0,0067) and of PT (from 8,36 to 9,7 seconds in ASA I, P<0,0323; and from 8,32 to 9,34 seconds in the ASA II and III dogs) between the pre and post anesthetic moments. These increases attendance decease in the colloid osmotic pressure, indicating that the anesthetic, surgical and fluid therapy procedures can cause hemodilution, and consequent increase in the blood clotting times.

This work aimed to elucidate basic aspects of the influence of chemical structure and surface topography on the surface properties of a polymer material in order to minimize the work of adhesion. End-functionalised aromatic perfluorinated oligo/polyesters have been chosen to clarify effect of chemical structure. Here, the comprehensive investigation of the influence of molecular architecture on processes of fluorine segregation in the topmost surface layer and surface properties of the end-functionalised aromatic perfluorinated linear and branched oligo-and polyesters were performed. It has been shown, that the character of the surface segregation of fluorinated moieties can be influenced by different factors i.e. conditions of preparation of polymer layers (by means of spin-coated and melt films), chemical structure of fluorinated tail and polymer backbone and slightly by molecular weight. Analysis of obtained results allows distinguishing contribution of each factor. Experimentally obtained results showed a good correlation with Scheutjens-Fleer self-consistent mean-field theory extended by Kumar and Koberstein, which corresponds to the surface segregation of various chemical functional moieties located on functional polymers of different architectures. In correlation with a self-consistent field approach, observed results confirmed that polymers with end fluorinated groups are promising for producing of low-energy surfaces.The effect of surface topography has been studied on the example of regular and irregular structured surfaces fabricated from core-shell particles. A simple and effective approach for designing regularly patterned surfaces with specifically designed surface roughness and chemistry using core-shell colloidal particles was demonstrated. The chemistry was varied by covalent grafting of polymer brushes onto silica particles or by chemisorption of fluorosilane. The modified colloidal spheres were organized into closely packed hemispherical hexagonal arrays either by a vertical deposition technique or by sedimentation on slightly inclined coated silicon wafers. In this way, an increase in the vertical roughness was achieved with increasing particle radius, but without changing the Wenzel roughness factor. Controllable variations in the surface chemistry and morphology were used for a systematic study of the wetting phenomenon on regular structured arrays. The regularity and periodicity of particle structures allowed modelling of wetting. The wetting was modelled according to WENZEL, CASSIE-BAXTER, EXTRAND theories as well as minimal and maximal possible contact angles introduced by SHUTTLEWORTH and BAILEY.It has been found that none of these theories completely describe the experimental results for all particle sizes except for the surfaces made from 0.2 Mikrometer large particles. It was revealed that wetting behaviour on fluorosilane modified particles with the diameter of 0.2 Mikrometer is close to the equilibrium contact angle described by WENZEL and CASSIE-BAXTER theories. It has been shown that the deviations contact angle from equilibrium state increase with increasing particle size, decreasing intrinsic contact angle, and increasing solid free energy of the particle ´shell´. This provides the experimental evidence for the theory proposed by JOHNSON and DETTRE. It was revealed that ultrahydrophobic surfaces couldn´t be observed on layers made from regularly packed core-shell particles. Design of fractal irregular surfaces is an appropriate way for preparation of ultrahydrophobic self-cleaning surfaces. It was demonstrated that fluorination is not an obligatory factor for design of water repellent coatings. The obtained results are of essential interest for industrial application.

Diplomová práce se zabývá výrobou a využitím zlatých koloidních nanotyčinek v biomedicínských aplikacích. Konkrétně se zaměřuje na tři základní funkce nanočástic v analýze - transportní, separační a především zobrazovací. V části o využití nanočástic pro zobrazování je hlavní zájem věnován zejména povrchové plazmonové rezonanci zlatých nantyčinek. Dále je práce zaměřena na využití nanotyčinek pro termální terapii. Následující část je věnována vhodným modifikacím povrchu, hlavně za účelem zmírnění toxicity částic. Závěrem teoretické části jsou způsoby přípravy zlatých koloidních nanotyčinek a techniky jejich následné analýzy. V navazující experimetální části jsou uvedeny postupy, podmínky a výsledky provedených pokusů.

Smartphones, schnell faltbar für die Hosentasche, ein Laptop, dünn wie Papier mit gestochen scharfem Kontrast, transparente Displays in Windschutzscheiben von Fahrzeugen, oder Fensterscheiben - Diese Technologien werden zunehmend als reale Szenarien diskutiert und haben Eines gemeinsam. Ihre Verwirklichung wird erst durch den Einsatz organischer Leuchtdioden (engl. organic light emitting diode, OLED) ermöglicht. Vor allem in internetbasierten Technologien, sowie neuartiger Displaytechniken und modernem Lichtmanagement wurde das Potential der OLEDs von der Industrie erkannt. Im Vergleich zu herkömmlichen Leuchtmitteln zeichnen sich OLEDs durch eine hohe Energieeffizienz aus. Ihre herausragende Eigenschaft als einzige Lichtquelle, direkt flächiges Licht abzugeben und zudem die Möglichkeit des Aufbaus aus flexiblen, transparenten Dünnschichten geben den OLEDs eine Sonderstellung für diese zukünftigen Anwendungen. Auch die steigende Anzahl an OLED-gestützten Produkten wie Bildschirmen, Smartphones und anderen Displaybauteilen zeigt diesen Trend deutlich. Dabei besteht für die industrielle Nutzung jedoch noch Forschungsbedarf. Diese Maßnahme wird mit Mitteln aus dem Europäischen Sozialfond gefördert und mitfinanziert durch Steuermittel auf Grundlage des von den Abgeordneten des Sächsischen Landtags beschlossenen Haushaltes.

<p>Approximately 30% of Canadians and 50% of Americans rely on groundwater for their domestic water supplies. A significant portion of this groundwater originates from fractured rock aquifers, as they are ubiquitous throughout North America. In comparison to unconsolidated porous media aquifers, relatively little is understood about biocolloid transport in fractures. A mechanistic understanding of the transport and retention of biocolloids in fractures is important towards determining the risk of biocolloid contamination to these sources, which can have a significant impact on human health. It has been well documented in the interfacial science literature that micro-scale hydrodynamics play a significant role in the transport of particles greater than approximately one micron in diameter, but do not significantly affect the transport of smaller particles. This phenomenon, however, has never been investigated in fractures,where the larger-scale hydrodynamics are complex, and must also be considered. To bridge this knowledge gap, this research was conducted to elucidate the effects of hydrodynamics on the transport and retention of <em>E. coli </em>RS2GFP and carboxylate modified yellow-green polystyrene (CMP) microspheres (0.05 μm diameter) in single, saturated, fractures at the laboratory scale.</p> <p>To achieve this goal, dolomitic limestone samples were acquired from a quarry in Guelph, Ontario, and were fractured under a uniaxial force. The hydrologic properties of each fracture sample were characterized using hydraulic and solute tracer tests. Using a factorial design approach, a known number of either <em>E. coli </em>RS2-GFP or CMP microspheres was released into the fracture under a range of specific discharges (30, 10 and 5 m/day). The resulting effluent concentration profiles were compared to isolate the effects of hydrodynamics on particle transport.</p> <p>Comparing and contrasting the effluent concentration profiles from these experiments revealed that hydrodynamic forces strongly influence the retention of particles larger than 1 μm in diameter in saturated, fractured media. Additionally, the mechanisms that dominate transport and retention are dependent on, and therefore vary with both specific discharge and particle size.</p> / Master of Applied Science (MASc)

[pt] O uso de surfactantes zwitteriônicos em projetos de recuperação avançada de petróleo está limitado à adsorção na superfície da rocha-reservatório, que deve ser prevista para determinar a viabilidade econômica desses projetos. Porém, existe uma falta de modelos capazes de estimar essa adsorção e explicar os mecanismos envolvidos. O objetivo do trabalho foi providenciar modelos que pudessem estimar a adsorção de um surfactante zwitteriônico (CAPB), e explicar seus mecanismos de adsorção. Os experimentos foram realizados em rochas do tipo carbonato e arenito, através de testes com rocha particulada (estáticos) e no interior de núcleos de rocha (dinâmicos). Foi desenvolvida uma metodologia para quantificar o CAPB em salmoura utilizando a cromatografia líquida de alta eficiência. Como um diferencial, a adsorção foi normalizada pela área superficial específica da rocha, através de análise BET (testes estáticos) e microtomografia com (micro)CT-scan (testes dinâmicos). Os resultados foram interpretados com modelos empíricos e teóricos integrados às estimativas de potencial de superfície. Verificou-se para o carbonato, que a primeira camada de adsorção segue um padrão homogêneo, limitada por repulsão eletrostática com a superfície, enquanto a segunda camada segue uma adsorção heterogênea, onde são formados agregados de surfactante mediados por interações hidrofóbicas entre as caudas. Para o arenito, as duas camadas têm uma distribuição heterogênea, explicando a maior adsorção entre as duas rochas. Concluiu-se que os modelos de dupla camada são capazes de explicar e estimar a adsorção em condições de fluxo de forma confiável e a área superficial foi o fator mais relevante na diferença de adsorção dinâmica entre rochas, favorecida no arenito. / [en] The use of zwitterionic surfactants in enhanced oil recovery projects is limited to adsorption on the surface of the reservoir rock, which must be predicted to determine the economic feasibility of these projects. However, there is a lack of models capable of estimating this adsorption and explaining the involved mechanisms. The objective of this study was to provide models that could estimate the adsorption of a zwitterionic surfactant (CAPB) and explain its adsorption mechanisms. Experiments were conducted on carbonate and sandstone rocks using static tests with particulate rock and dynamic tests within rock cores. A methodology was developed to quantify CAPB in brine using high-performance liquid chromatography. As a distinguishing feature, the adsorption was normalized by the specific surface area of the rock, determined through BET analysis (static tests) and microtomography with (micro)CT-scan (dynamic tests). The results were interpreted with empirical and theoretical models integrated with surface potential estimates. For carbonate, it was observed that the first layer of adsorption follows a homogeneous pattern, limited by electrostatic repulsion with the surface, while the second layer follows heterogeneous adsorption, forming surfactant aggregates mediated by hydrophobic interactions between the tails. For sandstone, both layers exhibit a heterogeneous distribution, explaining the higher adsorption between the two rocks. It was concluded that bilayer models are capable of reliably explaining and estimating adsorption under flow conditions, and the surface area was the most relevant factor in the difference of dynamic adsorption between rocks, favored in sandstone.

<p dir="ltr">The modern view of the plasma membrane is that of a complex, highly dynamic, compartmentalized system that critically impacts multiple important cellular functions. Supported model membranes of well-defined compositions have emerged as attractive experimental platforms to determine the underlying molecular processes that regulate membrane-associated cellular functions using advanced biophysical detection methods with up to single molecule resolution. However, membrane properties of previously employed supported membrane systems, such as solid-supported lipid bilayer (SLB) and polymer-supported lipid bilayer with a polymer layer thickness of several nm, were found to be perturbed by the nearby solid substrate. To overcome this limitation, the present work describes for the first time the capillary-assisted formation of a lipid bilayer (CA-PGB) on the surface of a fully hydrated, several micrometers thick polyacrylamide gel. CA-PGB formation can be accomplished by physisorption or specific chemical linkages (tethering) between polymer gel and bilayer. Not dissimilar to conditions found in plasma membranes, membrane properties of CA-PGB are found to be solely influenced by the attached polymer layer. The successful formation and lipid fluidity of CA-PGB is confirmed using confocal microscopy and fluorescence correlation spectroscopy (FCS). Lipid bilayer spreading on the hydrogel surface by capillary-assisted assembly is not altered when the polymer gel stiffness or bilayer bending stiffness are varied, illustrating the robustness and versatility of the assembly process. This work also shows that, unlike other supported membrane systems, the capillary-assisted assembly approach causes the formation of a lipid reservoir at the edge of the capillary. This lipid reservoir provides a lipid supply for the CA-PGB, enabling bilayer self-healing and superior bilayer stability relative to SLB. Experimental data are presented that support an assembly process, in which bilayer spreading on the gel surface inside the water capillary between two substrates is caused by monolayer collapse of suddenly accumulated lipids at the air-water interface of the capillary during sandwiching. A key aspect of the monolayer collapse-induced bilayer spreading is its rapid kinetics, which appears to be faster than the polymer gel swelling kinetics. The importance of the fast kinetics of bilayer spreading during capillary-assisted assembly is supported by the observation that attempts to build polymer gel-supported lipid bilayer using traditional lipid assembly methods [i. e., Langmuir-Blodgett (LB)/Langmuir-Schaefer (LS), LB- vesicle fusion, and spontaneous bilayer spreading from a hydrated lipid source], characterized by slower bilayer spreading kinetics, are unable to form a homogeneous fluid lipid bilayer on the polymer gel surface. The experimental results obtained in this work strongly suggest that the CA-PGB not only represents a powerful experimental model membrane platform for the analysis of membrane-associated processes relevant in cellular membranes, but also serves as promising cell surface mimetic to probe the cellular mechanosensitivity of adherend cells.</p>

This thesis presents an investigation of the dynamic properties of wide range of interfacial systems, from colloidal particles in solution, through the realm of aerosols and onto studies of molecular adsorption at an interface. The primary experimental technique utilized is optical tweezers. An exploration of the history of the use of radiation pressure to manipulate matter is presented, followed by an introduction to how optical tweezers work. Some of the more advanced methods of tweezing are discussed, with an emphasis on the use of spatial light modulators (SLMs) to realise dynamic holographic optical tweezers (DHOTs), an example of which has been constructed within our laboratory using off-the-shelf optical components, and combined with a spectrometer to facilitate high resolution spectroscopic studies of microscopic systems. The spectroscopic analysis of microparticles is greatly enhanced by optical feedback generated when the wavelength of light utilized is an integer number of wavelengths around the circumference of the microsphere. Enhanced signal occurs at these wavelengths, termed whispering gallery modes (WGMs). The absolute position of these resonances depends strongly upon the shape, size and refractive index of the particle, and is predicted by Mie theory. A discussion of the concepts behind Mie theory, as well as how to use an experimental WGM spectrum to deduce the size and composition of a microparticle, is provided. This technique is then put to use in a detailed study on the properties of single aerosols, comprised of sodium chloride solution, and generated using a handheld medical nebulizer. Studies have been carried out on both evaporating and growing droplets trapped with a Gaussian beam; in the latter case, periods of size stability are observed, owing to resonant absorption of radiation at the trapping laser wavelength. The SLM can be used to change the trapping laser to a Laguerre-Gaussian (LG) mode, and an investigation of how this affects the dynamics of the droplet is presented. It is found that the use of LG modes with $ellgeq10$ produced Raman spectra with significantly more intense WGMs, and also suppressed droplet evaporation. Through observations made with fluorescent polystyrene microspheres, it is argued that the LG modes are more efficient at coupling into WGMs of the droplets. Leading on from these experiments on salt water droplets, experiments have been conducted using ionic liquids (ILs). These fluids have many fascinating properties and potential applications. The optical trapping of droplets comprised of aqueous solutions of the ionic liquid ethylammonium nitrate (EAN) and water has been demonstrated for the first time. These droplets are analysed spectroscopically by illuminating them with the output from a broadband LED; WGMs that are observed in the backscattered light are used to determine their size and composition. The response of the droplets to conditions of varying relative humidity has also been investigated. In order to characterise the relative humidity experienced by both the salt water and IL droplets, the concentration of water vapour within the trapping cells has been measured using diode laser absorption spectroscopy. The spatially modulated laser beam is then utilized in a different fashion; instead of optically tweezing a sample, a low numerical aperture objective lens is utilized to focus the laser onto the surface of a gold coated microscope slide. When a colloidal sample is placed on this surface, the thermal gradients cause the particles to form two dimensional crystals. The SLM is utilized to form multiple nucleation sites, and the dynamics of the crystals are directly observed in real time using video microscopy. It is found that grain rotation-induced grain coalescence (GRIGC) occurs, with the rotation of both crystals before coalescence. Control over the grain size is achieved by altering the separation of the laser spots, and shows that the time scale for grain boundary annealing in our system is in good agreement with theoretical expressions formulated for nanocrystal growth. Finally, as a complimentary technique to the microparticle spectroscopy previously discussed, a bulk interface is probed by using evanescent wave broadband cavity enhanced absorption spectroscopy (EW-BBCEAS) specifically to study the adsorption of cytochrome c (cyt c) to a fused silica surface. Visible radiation from a supercontinuum source is coupled into an optical cavity consisting of a pair of broadband high reflectivity mirrors, and a total internal reflection (TIR) event at the prism/water interface. Aqueous solutions of cyt c are placed onto the TIR footprint on the prism surface and the subsequent protein adsorption is probed by the resulting evanescent wave. The time integrated cavity output is directed into a spectrometer, where it is dispersed and analysed. The broadband nature of the source allows observation of a wide spectral range (ca 250 nm in the visible). The system is calibrated by measuring the absorption spectra of dyes of a known absorbance. Absorption spectra of cyt c are obtained for both S and P polarized radiation, allowing information about the orientation of the adsorbed protein to be extracted.

Nesta tese, dois projetos distintos que usaram a técnica do Espalhamento de Luz foram desenvolvidos. Estudou-se a influência de soluções concentradas de uréia sobre agregados supramoleculares de anfifilicos (ASA\'s), através de condutimetria, supressão de fluorescência e espalhamento de luz. A uréia causou aumento da concentração micelar crítica (CMC) em todos os sistemas micelares estudados. A uréia diminuiu a seletividade da ligação iônica entre cloreto e brometo em micelas de haleto de cetil-trimetil-amônio, estudada através de supressão de fluorescência. Este aditivo causou também aumento na segunda CMC de brometo de tetradeciltrimetil- amônio (TTAB) e diminuição do peso molecular das micelas em bastão formadas. Concluiu-se, desta primeira parte, que a uréia tende a interferir nas transições de fase apresentadas em sistemas micelares, provavelmente através da combinação dos mecanismos direto e indireto. A uréia apresenta potencial para uso como aditivo para modulação das propriedades estruturais de sistemas micelares. Na segunda parte da tese desenvolveu-se um sistema, baseado em espalhamento de luz, capaz de monitorar o peso molecular de polímeros durante a polimerização. O sistema foi eficiente no monitoramento da polimerização da N-vinil-pirrolidinona, mostrando que o peso molecular do polímero formado é constante durante a maior parte da reação. As teorias atuais de cinética de polimerização não foram capazes de explicar esse comportamento. / Light scattering techniques (static and dynamic) were used to detenninate the effect of urea on supramolecular aggregates and to monitor on-line molar mass ofpolymerization reactions. For the first set of investigation it was already established that urea increases the CMC and the dissociation degree (&#945;) of ionic micelles (CTABr, TTABr, and SDS). From fluorescence suppression studies it was found that urea diminishes the ionic binding in zwitterionic and cationic micelles as well as in cationic vesicles. Bromide and chloride ionic selectivity in cationic micelles was found to nearly disappear in the presence of urea. Light scattering (static) detenninations showed that the weight averaged molecular weight (Mw) ofboth SDS and CTABr are invariant by the presence of the denaturant. A slight increase in the excluded volume tenn (A2) was detected for CTABr in the presence of 3M urea. In parallel both A2 and the radius of gyration (&#947;) of two polyelectrolytes (PAA and Hyaluronic acid) were not affected by the presence of urea. Sphere-to-rod concentration transitions (2nd CMC) of TIABr micelles increased in the presence of urea and the MW of rod particles were observed to decrease. For the insoluble mixture of CTABr/Polystyrenesulfonate solubilization was achieved in the presence of 3M urea. These set of results were explained as a result of the dual effect of urea, that is, the indirect effect by changing the properties of the solvent and the direct effect by solvating the hydrophilic domain of the aggregates and contributing with a stronger dipole moment. The second set of experiments was directed towards the real-time, on-line monitoring of Mw of polymerization reactions. This new approach could be succeeded by the coupling a light scattering detector, an UV photometer and a differential refractometer on line with a HPLC system. Mw growth formed in the polymerization of N-vynil-pirrolidone was accomplished with a small inherent error. Within the studied conditions Mw reached a plateau at early polymerization stages, after that only an increase in the number of polymer kinetic chains was observed. Current kinetic models were unable to predict the observed Mw growth pattern. This system is of great importance in basic and technological applications by virtue of its on-line capability.