[pt] Inúmeros estudos têm sido realizados para melhor entender a formação e estabilidade de emulsões. Em algumas situações, é desejável ter emulsões estáveis; em outros, a separação de fases por coalescência de gotas é benéfica. Em ambos os casos, é importante entender os mecanismos associados ao processo de coalescência. O presente trabalho investiga a relação entre as propriedades reológicas das interfaces óleo-água e o tempo de drenagem de um filme fino de óleo entre duas gotas aquosas. A tensão interfacial e a reologia dilatacional interfacial foram medidas usando a análise axissimétrica da forma da gota. Foram avaliadas diferentes concentrações de um tensoativo não iônico (Span 80) dissolvido em óleo mineral (Primol 352). Os resultados indicam uma relação direta entre as propriedades da estrutura formada na interface óleo-água e a ausência de coalescência das gotas. Para concentrações de surfactante abaixo da concentração micelar crítica (CMC), a interface é fracamente elástica (fluid-like) e o processo de coalescência sempre ocorre; o tempo de drenagem não está relacionado ao tempo de envelhecimento da interface. Para concentrações de surfactante acima da CMC, os módulos elástico e viscoso mostraram mudanças significativas com o envelhecimento, levando à formação de um filme sólido na interface, impedindo a coalescência entre as gotas. Usamos experimentos de coalescência gota/gota para avaliar o efeito da reologia interfacial na dinâmica de coalescência. Para entender melhor o fenômeno da não coalescência, estudamos microscopicamente a estrutura do filme interfacial e observamos o aparecimento de pequenas gotas de água formadas na interface através de emulsificação espontânea. Descobrimos que a taxa de surgimento dessas microgotículas está diretamente relacionada à concentração de surfactante. À medida que a concentração de surfactante aumenta, mais rápido ocorre o processo de emulsificação espontânea, o que confirma os resultados obtidos com a reologia interfacial. Finalmente, um novo método para promover a desestabilização da emulsão impondo uma perturbação do filme interfacial pelo escoamento das gotas através de capilares constritos é proposto e testado. / [en] Several studies have been conducted to understand emulsions formation and stability. In some situations, it is desirable to have stable emulsions; in others, phase separation through drop coalescence is beneficial. In both cases, it is important to understand the mechanisms associated to the coalescence process. The present work investigates the relationship between rheological properties of oil-water interfaces and the drainage time of a thin oil film between two aqueous drops. Interfacial tension and dilatational rheology were measured using the axisymmetric drop shape analysis. We evaluated different concentrations of a nonionic surfactant (Span 80) dissolved in mineral oil (Primol 352) phase. The results indicate a direct relationship between the properties of the structure formed at the oil-water interface and the absence of droplet coalescence. For low surfactant concentrations, below the critical micelle concentration (CMC), the interface is weakly elastic (fluid-like) and the coalescence process always occurs; the draining time is not to related to the aging time of the interface. For surfactant concentrations above CMC, the elastic and viscous moduli showed significant changes with aging leading to the formation of a solid-like film at the interface preventing further coalescence. We used a drop/drop coalescence experiments to evaluate the effect of interfacial rheology on the coalescence dynamics. To better understand the phenomenon of non-coalescence, we study the structure of interfacial film microscopically and observe the appearance of small water droplets formed at the interface by spontaneous emulsification. We found that the emergence rate of these microdroplets is directly related to the surfactant concentration. As the surfactant concentration increases, faster the spontaneous emulsification process occurs, which confirms the results obtained with the interfacial rheology. Finally, a new method to promote emulsion destabilization by imposing a perturbation of the interfacial film by flowing the drops through constricted capillaries is proposed and tested.

[pt] A adsorção de moléculas de asfalteno na interface óleo-água induz a formação de uma microestrutura complexa, que estabiliza as emulsões e prejudica a eficiência dos processes de refino de petróleo. Neste trabalho, desenvolvemos um conjunto de novos protocolos de reologia de cisalhamento para avaliar o efeito de solventes polares e apolares na adsorção de genuínos asfaltenos brasileiros. Além disso, a morfologia do asfalteno, após a adição de solventes com aromaticidades distintas, é investigada por microscopia de varredura (MEV). Os resultados indicam que os asfaltenos estão organizados em uma estrutura do tipo ilha com unidades aromáticas e policondensadas, que formam filmes interfaciais reversíveis com a adição de solventes polares. O estudo interfacial também revela que solventes apolares podem "prender" os nanoagregados de asfalteno na mistura. Esses agregados, na presença de solventes fracamente polares, podem se consolidar em um padrão mais compactado, sugerindo que o crescimento do filme e o autoarranjo do asfalteno estão diretamente relacionados ao conteúdo aromático. Explora-se as diferenças na estruturação do asfalteno e como afetam a extensão da emulsificação espontânea. É proposto que a taxa de emulsificação está diretamente relacionada à configuração química dos asfaltenos. Finalmente, estuda-se a adição de ácido esteárico (AE) a soluções de asfalteno em conteúdo de água deionizada (AD) e água sintética (AS) para melhor compreender como as propriedades reológicas e superficiais são afetadas pela competição das coespécies. Verifica-se que interfaces formadas puramente por AEs originam filmes mais viscosos do que elásticos na interface ar-água. A atividade interfacial dos asfaltenos brasileiros é evidente e significativa na presença de eletrólitos e dependente da aromaticidade do solvente. / [en] Adsorption of asphaltene molecules at the oil-water interface induces the formation of a complex microstructure, which stabilizes emulsions and impairs the efficiency of crude oil refining. In this work, we design a set of new shear rheology protocols to assess the effect of polar and non-polar solvents on indigenous Brazilian (BR) asphaltene adsorption. Moreover, the asphaltene morphology upon addition of solvents with distinct aromaticities is investigated by SEM microscopy. Our findings indicate that asphaltenes are a polycondensate aromatic island-type structure that forms reversible films when polar solvents are placed on top of the adsorbed film. The interfacial study also reveals that non-polar solvents may lock up asphaltene nanoaggregates in mixture. These aggregates, upon the presence of weakly polar solvents, can consolidate into a more close-packed pattern, suggesting that network growth and asphaltene self-arrangement are directly related to the aromatic content. We explore the differences in asphaltene structuring and how it affects the extent of spontaneous emulsification. We find that the rate of emulsification is directly related to the chemical configuration of asphaltenes. Finally, we study the addition of stearic acid (SA) to asphaltene solutions in deionized water (DW) and synthetic water (SW) to better understand how surface and rheological properties are affected by competitive adsorption. We find that single SA are more prone to form liquid-like rather than solid-like films at the air-water interface. Furthermore, we show that the interfacial activity of our asphaltenes is enhanced in the presence of electrolytes and is dependent of the solvent aromaticity.

[pt] No âmbito da indústria de petróleo e gás, a interrupção das linhas de produção e transporte devido à acumulação de compostos orgânicos e inorgânicos representa um desafio generalizado e significativo, resultando em consideráveis perdas financeiras e apreensões ambientais. Os hidratos de gás, particularmente enfatizados entre vários desafios relacionados à deposição inorgânica, apresentam uma questão complexa caracterizada pela formação de sólidos cristalinos à base de água, semelhantes ao gelo, ocorrendo sob condições de pressão elevada e baixas temperaturas que se formam quando moléculas leves de hidrocarbonetos e água se combinam para formar uma estrutura ordenada específica. A formação de hidrato começa na interface água-hidrocarboneto, o que destaca o papel crítico que a reologia interfacial desempenha neste processo. Apesar da importância desta interface na formação de hidratos, persiste uma lacuna na pesquisa, particularmente no emprego de abordagens de reologia de cisalhamento. Este estudo ajuda a preencher essa lacuna investigando as propriedades mecânicas e de fluxo da interface, utilizando um recurso em um reômetro rotacional, uma célula de anel de parede dupla, para controle preciso da temperatura. O ciclopentano serve como formador de hidrato, permitindo a experimentação sob condições atmosféricas. pressão e temperaturas variadas. Os protocolos exploram a temperatura e as concentrações de hidrocarbonetos, com ênfase no envolvimento dos cristais de gelo no início da formação de hidratos. Após a saturação completa da interface hidrocarboneto/água por hidratos, os módulos elásticos e viscosos interfaciais são obtidos através de varreduras de deformação para avaliar a fragilidade do filme de hidrato e resposta mecânica. Além disso, é examinado o impacto do tempo de envelhecimento e do tipo de cisalhamento (estático ou dinâmico) na rigidez do hidrato. Testes com inibidores termodinâmicos, como cloreto de sódio e monoetilenoglicol, demonstram extensão significativa do tempo de indução. Além disso, mudanças sistemáticas na taxa de cisalhamento são investigadas para compreender de forma abrangente sua influência nas características e propriedades do filme hidratado sob diversas condições de histórico de cisalhamento. No geral, esta pesquisa lança luz sobre as nuances da dinâmica da interface águahidrocarboneto na formação e mitigação de hidratos. / [en] Within the realm of the oil and gas industry, the disruption of production and transportation lines due to the accumulation of organic and inorganic compounds poses a widespread and significant challenge, resulting in considerable financial losses and environmental concerns. Gas hydrates, particularly emphasized among various challenges related to inorganic deposition, present a complex issue characterized by the formation of crystalline water-based solids, akin to ice, occurring under conditions of high pressure and low temperatures that arise when light hydrocarbon molecules and water combine to form a specific ordered structure. Hydrate formation begins at the water-hydrocarbon interface, highlighting the critical role interfacial rheology plays in this process. Despite the importance of this interface in hydrate formation, a research gap persists, particularly in the employment of shear rheology approaches. This study aids in bridging this gap by investigating the mechanical and flow properties of the interface, utilizing a resource in a rotational rheometer, a double-wall ring cell, for precise temperature control. Cyclopentane serves as the hydrate former, allowing experimentation under atmospheric pressure and varied temperatures. Protocols explore temperature and hydrocarbon concentrations, with an emphasis on the involvement of ice crystals in the early stages of hydrate formation. Following complete saturation of the hydrocarbon/water interface by hydrates, interfacial elastic and viscous moduli are obtained through strain sweeps to assess hydrate film fragility and mechanical response. Additionally, the impact of aging time and shear type (static or dynamic) on hydrate stiffness is examined. Tests with thermodynamic inhibitors, such as sodium chloride and monoethylene glycol, demonstrate a significant extension of the induction time. Furthermore, systematic changes in shear rate are investigated to comprehensively understand their influence on the characteristics and properties of the hydrated film under various shear history conditions. Overall, this research sheds light on the nuances of waterhydrocarbon interface dynamics in hydrate formation and mitigation.

Organic coatings are widely used to lower the corrosion rate of metallic structures. However, penetration of water, oxygen and corrosive ions through pores present in the coating results in corrosion initiation and propagation once these species reach the metal substrate. Considering the need for systems that offer active protection with self-healing functionality, composite coatings containing polyaniline (PANI) conducting polymer are proposed in this study. In the first phase of my work, PANI was synthesized by various methods and characterized. The rapid mixing synthesis method was chosen for the rest of this study, providing PANI with high electrical conductivity, molecular structure of emeraldine salt, and morphology of spherical nanoparticles. PANIs doped with phosphoric and methane sulfonic acid revealed hydrophilic nature, and I showed that by incorporating a long-chain alkylphosphonic acid a hydrophobic PANI could be prepared. The second phase of my project was dedicated to making homogenous dispersions of PANI in a UV-curable resin based on polyester acrylate (PEA). Interfacial energy studies revealed the highest affinity of PEA to PANI doped with phosphoric acid (PANI-PA), and no attractive or long-range repulsive forces were measured between the PANI-PA surfaces in PEA.This is ideal for making conductive composites as, along withno aggregation tendency, the PANI-PA particles might come close enough to form an electrically connected network. Highly stable PEA/PANI-PA dispersions were prepared by pretreatment of PANI-PA in acetone followed by mixing in PEA in small portions under pearl-milling. The third phase of my project dealt with kinetics of the free radical polymerization that was utilized to cure the PEA/PANI-PA mixture. UV-vis absorption studies suggested a maximum allowed PANI-PA content of around 4 wt.% in order not to affect the UV curing behavior in the UV-C region. Real-time FTIR spectroscopy studies, using a laboratory UV source, revealed longer initial retardation of the photocuring and lower rates of crosslinking reactions for dispersions containing PANI-PA of higher than 3 wt.%. The presence of PANI-PA also made the formulations more sensitive to changes in UV light intensity and oxygen inhibition during UV curing. Nevertheless, curing of the dispersions with high PANI-PA content, of up to 10 wt.%, was demonstrated to be possible at either low UV light intensities provided the oxygen replenishment into the system was prevented, or by increasing the UV light intensity to very high levels. In the last phase of my project, the PEA and PEA/PANI-PA coatings, cured under high intensity UV lamps, were characterized. SEM analysis showed small PANI-PA particles to be closely packed within the matrix, and the electrical conductivity of the composite films was measured to be in the range of semiconductors. This suggested the presence of a connected network of PANI-PA, as confirmed by investigations of mechanical and electrical variations at the nanoscale by PeakForce TUNA AFM. The data revealed the presence of a PEA-rich layer at the composite-air interface, and a much higher population of the conductive network within the polymer matrix. High current signal was correlated with a high elastic modulus, consistent with the level measured for PANI-PA, and current-voltage studies on the conductive network showed non-Ohmic characteristics. Finally, the long-term protective property of the coatings was characterized by OCP and impedance measurements. Short-term barrier-type corrosion protection provided by the insulating PEA coating was turned into a long-term and active protection by addition of as little as 1 wt.% PANI-PA. A large and stable ennoblement was induced by the coatings containing PANI-PA of up to 3 wt.%. Higher content of PANI-PA led to poorer protection, probably due to the hydrophilicity of PANI-PA facilitating water transport in the coating and the presence of potentially weaker spots in the film. An iron oxide layer was found to fully cover the metal surface beneath the coatings containing PANI-PA after final failure observed by electrochemical testing. / <p>QC 20141103</p>

Master of Science / Department of Mechanical and Nuclear Engineering / Kevin Lease / Carbon fiber reinforced composites (CFRP’s) are a mainstay in many industries, including the aerospace industry. When composite components are damaged on an aircraft, they are typically repaired with a composite patch that is placed over the damaged material and cured into the existing composite material. This curing process involves knowledge of the curing time necessary to sufficiently cure the patch. The inexact nature of curing composites on aircraft causes a significant waste of time and material when patches are unnecessarily redone. Knowing how differences in cure cycle affect the strength of the final material could reduce this waste. That is the focus of this research. In this research, the interfacial shear strength (IFSS) of carbon fiber/epoxy composites was investigated to determine how changes in cure cycle affect the overall material strength. IFSS is a measure of the strength of the bond between the two materials. To measure this, the microbond method was used. In this method, a drop of epoxy is applied to a single carbon fiber. The specimen is cured and the droplet is sheared from the fiber. The force required to debond the droplet is recorded and the data is analyzed. The IFSS of AS4/Epon828, T650/Epon828, and T650/Cycom 5320-1 composites were evaluated. For the former two material systems, a cure cycle with two steps was chosen based on research from others and then was systematically varied. The final cure time was changed to determine how that parameter affected the IFSS. It was found that as the final cure time increased, so did the IFSS and level of cure achieved by the composite to a point. Once the composite reached its fully cured state, increasing the final cure time did not noticeably increase the IFSS. For the latter material system (T650/Cycom 5320-1), the two cure cycles recommended by the manufacturer were tested. These had different initial cure steps and identical final cure steps. Although both cure cycles caused high IFSS, the cycle with the higher initial temperature, but shorter initial cure time achieved a higher level of cure than that with a longer time, but shorter temperature.

The increasing demand for energy in combination with a greater awareness for our environmental impact have encouraged the development of sustainable energy sources, including materials for energy storage. Latent heat thermal energy storage by the use of phase change material (PCM) have become an area of great interest. It is a reliable and efficient way to reduce energy consumption. PCMs store and release latent heat, which means that the material can absorb the excess of heat energy, save it and release it when needed. By introducing soy wax as a biobased PCM and apply it on textile, one can achieve a thermoregulation material to be used in buildings and smart textiles. By replacing the present most used PCM, paraffin, with soy wax one cannot only decrease the use of fossil fuel, but also achieve a less flammable material. The performance of soy wax PCM applied on a textile fabric have not yet been investigated but can be a step towards a more sustainable energy consumption. The soy wax may also broaden the application for PCM due to its low flammability. The aim is to develop an environmental friendly latent heat thermal energy storage material to be used within numerous application fields.

Lithium-ion batteries with higher capacity and longer cycle life than that available today are required as secondary energy sources for a wide range of emerging applications. In particular, the cycling performance of several candidate materials for lithium-ion battery electrodes is insufficient because of the fast capacity fading and short cycle life, which is mainly a result of mechanical degradation. This dissertation mainly focuses on the issue of mechanical degradation in advanced lithium-ion battery electrodes. Thin films of tin electrodes were studied where we observed whisker growth as a result of electrochemical cycling. These whiskers bring safety concerns because they may penetrate through the separator, and cause short-circuit of the electrochemical cells. Cracking patterns generated in amorphous silicon thin film electrodes because of electrochemical cycling were observed and analyzed. A two-dimensional spring-block model was proposed to successfully simulate the observed cracking patterns. With semi-quantitative study of the cracking pattern features, two strategies to void cracking in thin-film electrodes were proposed, namely reducing the film thickness and patterning the thin-film electrodes. We also investigated electrodes consisting of low melting point elements and showed that cracks can be self-healed by the solid-to-liquid phase transformation upon cycling. Using gallium as an example, mechanical degradation as a failure mechanism for lithium-ion battery electrodes can be eliminated. In order to quantitatively understand the effect of surface modification on electrodes, we analyzed diffusion equations with boundary conditions of finite interfacial reactions, and proposed a modified potentialstatic intermittent titration technique (PITT) as an electro-analytical technique to study diffusion and interfacial kinetics. The modified PITT has been extended to thin-film geometry and spherical geometry, and thus can be used to study thin-film and composite electrodes consisting of particles as active materials.

Thermosonic ball bonding is a key technology in electrical interconnections between an integrated circuit and an external circuitry in microelectronics. Although this bonding process has been extensively utilised in electronics packaging industry, certain fundamental aspects behind all the practice are still not fully understood. This thesis is intended to address the existing knowledge gap in terms of bonding mechanisms and interfacial characteristics that are involved in thermosonic gold and copper ball bonding on aluminium pads. The research specifically targets the fine pitch interconnect applications where a thin metal wire of approximately 20 µm in diameter is commonly used. In thermosonic ball bonding process, a thin gold or copper ball formed at the end of a wire is attached to an aluminum pad through a combination of ultrasonic energy, pressure and heat, in order to initiate a complex solid-state reaction. In this research, the mechanisms of thermosonic ball bonding were elaborated by carefully examining interfacial characteristics as the results of the bonding process by utilising dual-beam focused ion beam and high resolution transmission electron microscopy, including the breakdown of the native alumina layer on Al pads, and formation of initial intermetallic compounds (IMCs). The effect of bonding parameters on these interfacial behaviours and bonding strength is also investigated in order to establish an inter-relationship between them. Interfacial evolution in both Au-Al and Cu-Al bonds during isothermal annealing in the temperature rage from 175ºC to 250ºC was investigated and compared. The results obtained demonstrated that the remnant alumina remains inside IMCs and moves towards the ball during annealing. The IMCs are formed preferentially in the peripheral and the central areas of the bonds during bonding and, moreover, they grow from the initially formed IMC particles. Growth kinetics of Cu-Al IMCs obey a parabolic growth law before the Al pad is completely consumed. The activation energies calculated for the growth of CuAl2, Cu9Al4 and the combination (CuAl2 + Cu9Al4) are 60.66 kJ/mol, 75.61 kJ/mol, and 65.83 kJ/mol, respectively. In Au-Al bonds, Au-Al IMC growth is controlled by diffusion only at the start of the annealing process. A t^0.2-0.3 growth law can be applied to the Au-Al IMC growth after the Al pad is depleted. The sequence of IMC phase transformation in both Au-Al and Cu-Al bonds were investigated. Voids in Au-Al bonds grow dramatically during annealing, however, only a few voids nucleate and grow very slowly in Cu-Al bonds. The mechanisms of void formation, including volumetric shrinkage, oxidation and metal diffusion were proposed and discussed.

A systematic study of the surface-initiated polymerisation kinetics of a relatively new type of atom transfer radical polymerisation (ATRP), activators regenerated by electron transfer (ARGET) ATRP, is first demonstrated in this report. Poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(methyl methacrylate) (PMMA) were successfully grown from silicon surfaces at room temperature by surface-initiated ARGET ATRP using a "3rd generation" cationic macroinitiator. The polymer films were analysed by ellipsometry, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). With the initial experiment showing that water accelerated conventional ATRP but made it less controlled, the effect of solvent on ARGET ATRP was also evaluated. The living character of ARGET ATRP was demonstrated by successfully reinitiating PHEMA-grafted silicon wafers to grow a second block of PHEMA. Initiator density was shown to have a great effect on the growth rate of PHEMA film thickness on silicon surfaces by comparing the ARGET ATRP growth of PHEMA films using two different initiators, "1st generation" and "3rd generation" cationic macroinitiators, which have different ratios of initiating groups to positive charge. Another type of initiator for ATRP systems, an amide silane, was then investigated as an alternative to polyelectrolyte macroinitiators to avoid degrafting. The effects of solvent, 2, 2′ bipyridyl (bpy) ligand concentration and different types of reducing agent on the growth of PHEMA film from amide-initiator coated silicon wafers by ARGET ATRP were then explored at room temperature. However, it was found that the swings in the uncontrolled laboratory ambient temperature caused inter-sample and inter-experiment variability and so could make the evaluations inaccurate or even wrong. An investigation of temperature on ARGET ATRP showed a dramatic effect on the polymerisation rate. The higher the temperature, the faster the polymerisation proceeded. Therefore, the effects of solvent, ratio of bpy to Cu and reducing agent on the ARGET ATRP growth of PHEMA brushes from amide initiator-coated silicon wafers were re-evaluated at a constant temperature, 30 °C. The development of a polydopamine-based initiator, which was designed to be able to be immobilised on a wide range of surfaces, is then presented in this report. Polydopamine was first shown to be able to deposit on various types of material surfaces by oxidative polymerisation in aqueous solution. Bromoester initiating groups for ATRP systems were incorporated into polydopamine coatings by reacting a fraction of the dopamine monomer with 2-bromoisobutyryl bromide (BIBB) before polymerisation. The modified polydopamine initiator film grew at a comparable rate to unmodified polydopamine, with a 45 nm being grown in 24 hours. Successful incorporation of initiator groups was confirmed by XPS and FTIR, and by the growth of PMMA and PHEMA polymer brushes by ARGET ATRP from the polydopamine initiator coatings. A PMMA brush with a thickness of 239 nm was grown in 72 hours, indicating that the grafting density is sufficiently high to be in the brush regime. This initiator was demonstrated to be able to deposit on a range of substrates, such as metals (steel) and polymers (polystyrene), and successfully initiate polymer growth, demonstrating its broad applicability. The assessment of ARGET ATRP as a simple and effective tool for interfacial shear strength improvement in cellulose-based fibre reinforced thermoplastic composites is finally presented. It was demonstrated by control experiments that grafting polystyrene on glass fibre surfaces via ARGET ATRP greatly improved the interfacial adhesion between glass fibres and a high-impact polystyrene (HIPS) matrix, although a specific value of interfacial strength was not obtained due to failure of the modified glass fibre composite samples in areas other than the interface. It was then demonstrated that PMMA was successfully grown from the surfaces of polydopamine initiator coated cotton fibre and BIBB-modified cotton fibre by ARGET ATRP. Polydopamine initiator was shown to be a better initiator for cotton fibre than BIBB, possibly since the adsorbed water on cotton fibres can react with BIBB. The improvement of interfacial adhesion between cotton fibres and a PMMA matrix by grafting PMMA on the cotton surface was assessed by peel testing of cotton fibres pressed into PMMA sheets. There is a clear trend in the relationship between the peeling force and growth time of PMMA on the cotton fibre by ARGET ATRP, although the inter-sample reproducibility is not good.

A fluid-fluid demixing colloid-polymer system provides us with an opportunity to study interfacial phenomena that cannot be observed in molecular systems due to unfavourable length and timescales. We develop such a system compatible with cells of varying dimensions, allowing us to investigate confined interfacial behaviour in real space using Confocal Scanning Laser Microscopy. The degree to which a system is affected by the sedimentation-diffusion gradient is dependent on the ratio of the suspension height to the gravitational length of the colloids. We illustrate that we may control the distance of our interface to the critical point by altering the suspension height, determining the importance of the gravitational field. Furthermore, the timescale on which the sedimentation- diffusion gradient is established is considerably longer than that of initial fluid-fluid demixing. We show that after the formation of the macroscopic interface, the system passes through a series of local mechanical equilibria on the way to achieving full equilibrium. Should the system be of sufficient height, it will pass through the gas-liquid critical point opening up new ways to study critical phenomena. The time and length scales of the fluid-fluid demixing of our system may be manipulated by altering the density and viscosity of our solvent. We exploit a slowed phase separation process to study the interplay between demixing and wetting phenomena of systems in the vicinity of a single wetting surface, and confined between two parallel plates. We demonstrate that the presence of a surface strongly affects the morphology of phase separation. The growth of the wetting layer is determined by the demixing regime of the system, and may be accelerated by hydrodynamics. The additional restriction by a second surface limits the lengthscale of coarsening domains and may further alter the mechanism of wetting layer growth.