The objective of this work was to investigate the behaviour of some model surfactants used in the deinking process, namely, sodium oleate and two ethoxylated nonionic surfactants (C12E6 and C14E6) as well as to investigate the suitability of various model substrates for mimicking interactions in technical systems. The influence of the adsorption to the air � water interface has been measured by means of equilibrium and dynamic surface tension measurements, as well as foaming experiments. It was found that the solution pH and temperature influenced the dynamic and equilibrium surface tensions and the value of the cmc. Equilibrium surface tension measurements were also performed with mixtures of sodium oleate and nonionic surfactants and a strong synergistic effect was obtained, which means that a greater surface tension reduction can be obtained at lower surfactant concentrations. The foaming experiments, carried out with a Foam Scan Apparatus, showed an approximately constant total foam volume for both the pure surfactant systems and for the mixtures. In addition, the foam was slightly more stable for the mixtures than for the pure components. Friction and surface forces between solid surfaces in liquid were studied using the atomic force microscope (AFM) from which inferences about the adsorption to these interfaces could be drawn. The AFM measurements were performed with the colloidal probe technique using cellulose as colloidal probe and an alkyd resin as a model ink surface. Mica and silica were both used as models for hydrophilic surfaces. Adsorption was observed on the alkyd resin, both with sodium oleate and with C12E6. The adsorption was registered both as a change in normal surface force interaction and as a strong reduction in friction force and friction coefficient at increasing surfactant concentration. The magnitude of the friction force was observed to be dependent on the adhesion and varied monotonically with the surface roughness. Measurements of adhesion and friction forces in air were performed, and the same conclusions about the effect of roughness were drawn. Finally the friction force behaviour appears to be similar if the adhesion is caused by a vapour bridge in liquid, or by a liquid bridge in air, where the formation of a capillary bridge in air is strongly dependent on the relative humidity. / QC 20100923

This doctoral thesis comprises three studies dealing with water-based flexography on polymer-coated boards, which have been presented in the five papers included at the end of the thesis. The first study (covered in three papers) presents results from characterisation of a matrix of water-based inks with respect to their rheology, surface tension, wetting, and fulltone printing performance on PE-coated board. The commercial water-based inks used vary in type of pigment and acrylic vehicle, and in pigment/vehicle mixing proportions. For all mixing proportions, the inks were shear thinning, with viscosity increasing strongly with content of solution (versus emulsion) polymer in the vehicle. Increasing amount of solution polymer also gave the indirect consequence of lower surface tension values. The wet ink amount transferred to the board and the resulting print uniformity responded sensitively to ink formulation and could be correlated to the corresponding changes in these two ink properties. Transferred amount correlated well with ink plastic viscosity and static surface tension, exhibiting a maximum at intermediate values of both. Print mottle decreased with increasing content of solution polymer, principally due to the associated increase in low-shear viscosity and decreased surface tension, both serving to reduce substrate dewetting. In the second study, the effect of corona discharge treatment of PE-coated board on its surface chemistry and print resistance properties was evaluated. The increase in total surface energy, due to its polar component, with increasing corona level was strongly correlated to surface oxidation fraction from XPS. AFM revealed oxidised material nano-mounds, which increased in size and substrate coverage with corona level. Wet rub resistance (with water) first increased for lower corona dosages before decreasing at higher dosages. This worsened water resistance at higher dosages is presumably due to the oxidised material dissolved and dispersed in the ink film. The third study presents results from another set of water-based acrylic inks printed on boards coated with PE, OPP and PP. Print quality and resistance properties, though dependent on the polymer type, were strongly influenced by the choice of emulsion polymer and presence of silicone additive in the vehicle, with corona treatment level playing a lesser role. The emulsion polymer giving best resistance performance was generally found to give poorest press performance and visual appearance. Again the trends could be understood in terms of wet ink surface tension (versus substrate surface energy), dictating print uniformity, and dry print surface energy (and swellability), dictating resistance properties. / QC 20100916

This thesis claims a relationship between the film splitting sound emission from the printing press nip and the dynamic interaction occurring there between ink, fountain solution and substrate in offset lithography. The film splitting sound derives from the cavitation formed by the pressure drop in the second half of the print nip flow passage. As the ink film is strained, the cavities expand and eventually implode into breaking filaments at the nip exit, while emitting a partly audible, broadband, high frequency, noisy sound. A free-field microphone, A/D-converter and laptop computer were used to record pressure signals in the frequency range of 10 Hz to 50 kHz emitted by a variety of printing instruments and presses for a range of offset ink and paper types. After signal acquisition and filtering two signal averages of power and frequency were estimated. This average power increased with increasing loads of sheet-fed offset ink on an ink distributor, in accordance with a mass-conservation model developed. The behaviour of average frequency and power over different ink load ranges indicated transitions between different flow regimes. A glossy fine-coated paper gave higher average power than a corresponding matte paper during printing with such inks on a laboratory device, possibly due to an air sealing effect. The sound from tack measurements with the Deltack instrument during setting of heat-set offset inks printed on MWC papers showed a relation between the measured tack rise and average power, reflecting changes in splitting mechanism during the course of setting. With the Hydroscope instrument the interaction between these heat-set inks and fountain solution was studied, with the measured tack and sound emission displaying a clear, but non-linear, correlation. A heat-set offset pilot trial showed that the acoustic response from the printing nip sensitively and systematically detected changes in (LWC) paper type, optical density, ink-fount balance, and press stability. Pilot trials of cold-set offset inks on newsprint by sheet-fed presses indicated a strong correlation between evolution in average power, optical density and fountain solution consumption during the first thousand sheets normally needed for stabilisation. Acoustic measurements of ink film splitting have, aside from the laboratory studies performed by one Japanese group, previously received little attention, with the current study showing that a great deal of information useful to the printer can be accessed from this sound emission. Although the detailed mechanisms for ink film splitting have to be further studied and supported by mathematical simulation, the sensitivity of the acoustic method recommends its implementation for monitoring and control of offset printing. / QC 20100928

Unspecific interactions, at the interface between a synthetic material and an aqueous biological environment, leading to irreversible protein adsorption can cause to undesired consequences. These include fouling of a boat hull or a triggered immune response. Thus, stealthy materials are a topic that has generated a great deal of interest in the scientific community. This work deals with the design of networks, nanoparticles, and surfaces containing poly(ethylene glycol) (PEG), known for its resistance to protein adsorption and non-toxic nature. Initially, PEG-based networks, hydrogels, were synthesized using photoinduced thiol-ene chemistry in order to afford coatings targeted for marine antifouling applications. By varying the length of the PEG chain, curing chemistry, cross-linker as well as hydrolytical stability, a library of hydrogel coatings was produced. The coatings were subsequently characterized with respect to curing efficiency, thermal and mechanical properties, and aqueous stability. Furthermore, the antifouling properties of coatings were evaluated using in vitro tests with proteins, marine bacteria, and diatoms. As a final test the coatings were evaluated in a four month field test. It was found that coatings comprising longer PEG chains displayed enhanced antifouling performance, compared to shorter PEGs. In addition, the choice of cross-linker, curing chemistry, and hydrolytical stability also affected the properties to a great extent. This thesis further deals with the design of amphiphilic linear dendritic hybrids, with PEG as the hydrophilic block. Using non-toxic 2,2-bis(methylol) propionic acid (bis-MPA) based dendrons, bearing click functional cores (alkyne or allyl) and peripheral hydroxyl groups, as macrointitiators for ring-opening polymerization of ε-caprolactone, a library of star branched materials was afforded. As a final step, click functional (azide or thiol) PEGs were attached using copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) or thiol-ene click chemistry. The size of the dendrons was varied from generation 0-4, along with variation of both poly(ε-caprolactone) (PCL) length and PEG length. The materials were designed in order to allow a study of the impact of the dendron generation. Finally, the hybrid materials were used for the preparation of micelles, as well as for the formation of honeycomb membranes. The micelles critical micelle concentration, size and drug loading capacity were shown to be highly dependent on the generation of the dendron. The generation of the dendron also had a profound effect on the ability of the hybrid materials to form ordered honeycomb membranes, and hybrid materials of the 3rd generation yielded the most highly ordered membranes. / Ickespecifika interaktioner vid gränsytan, mellan ett syntetiskt material och en vattenbaserad biologisk miljö, kan leda till irreversibel adsorption av proteiner. Detta kan i sin tur leda till oönskade följdeffekter, såsom beväxning på båtskrov eller trigga en immunologisk reaktion. För att motverka dessa effekter har forskare utvecklat så kallade smygmaterial. Denna avhandling behandlar design av nätverk, nanopartiklar och ytor innehållande poly(etylenglykol) (PEG), som är känt för sina smygegenskaper och för att vara icke-toxiskt. Initialt behandlar avhandlingen PEG-baserade nätverk, hydrogeler, syntetiserade med fotoinitierad tiol-enekemi, för användning som beväxningsavvisande beläggningar för marina applikationer. Genom att variera olika parametrar, såsom längden på PEG-kedjan, härdningskemin, tvärbindaren samt den hydrolytiska stabiliteten, byggdes ett bibliotek av hydrogelbeläggningar upp. Hydrogelbeläggningarna karaktäriserades sedan med avseende på härdningseffektivitet, termiska och mekaniska egenskaper, samt hydrolytisk stabilitet. Vidare studerades beläggningarnas avvisande förmåga mot proteiner, bakterier samt kiselalger. Slutligen studerades ytbeläggningarna i ett fyra månader långt fälttest. Av testerna framgick att längre PEG-kedjor gav beläggningar med bättre avvisande förmåga. Dessutom framgick att valet av tvärbindare, härdningskemi samt hydrolytisk stabilitet var av betydelse för beläggningarnas effektivitet. Denna avhandling behandlar vidare design av amfifila linjära dendritiska hybridmaterial, med PEG som den hydrofila delen. Genom att använda icke-toxiska 2,2-bis(metylol)propionsyrabaserade dendroner, med en klickfunktionalitet i kärnan (alkyne eller allyl) och perifera hydroxylgrupper, som makroinitiatorer för ringöppningspolymerisation av ε-kaprolakton byggdes ett bibliotek av material upp. För att göra materialen amfifila, kopplades klickfunktionella PEG-kedjor (azid eller tiol) till kärnan med koppar(I)-katalyserad azid-alkyn cykloadditionskemi alternativt tiol-enekemi. Storleken på dendronerna varierades från generation 0-4, dessutom varierades längden på både poly(ε-kaprolakton)- och PEG-kedjorna. Materialen designades så att inverkan av dendrongenerationen kunde studeras. Slutligen användes dessa hybridmaterial för att framställa miceller samt isoporösa filmer. Micellernas kritiska micellbildningskoncentration, storlek samt förmåga att laddas med läkemedel visade sig vara mycket beroende av dendrongenerationen. Dendrongenerationen visade sig vidare även ha stor inverkan i hybridmaterialens förmåga att självorganisera sig till en isoporös struktur och material av tredje generationen gav de mest välordnade filmerna. / QC 20101125

The environmental stability of a metal / polymer interface is essential for the durability and mechanical stability of constructions in several important areas such as the automotive, offshore, building and aerospace industries. The protective capability of a polymer film is strongly connected to its barrier properties, but the transport of water and corrosive constituents through the polymer and the subsequent processes at the metal surface are complicated to analyse in detail. The surface to be analysed is confined between two media that are impermeable to most probing particles used in conventional analytical techniques. Several methods exist to describe separate parts of the system, but few techniques work atambient pressure and have the capacity to conduct real-time analysis at relevant exposure conditions. In this work, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) in the Kretschmann geometry was successfully employed for systematic studies of metal / polymer interfaces. This technique requires the use of thin metal films deposited on an internal reflection element (IRE). Most studies were performed on aluminium, which is an important structural light-weight material, but also zinc was analysed, being frequently used for corrosion protection of steel. Upon exposure to water and electrolytes, the ATR-FTIR Kretschmann technique was found capable to monitor and to separate early deterioration related processes at the aluminium / polymer interface, including water sorption and transport of ionic species through the polymer film. Other main processes identified were the formation of corrosion products and swelling of the surface-near polymer network. To perform more comprehensive interpretations, a spectro-electrochemical method was further developed for in situ studies of the hidden metal / polymer interfaces. The ATR-FTIR Kretschmann technique was here combined with the complementary acting technique, Electrical Impedance Spectroscopy (EIS). The integrated set-up was able to provide complementary information, with ATR-FTIR Kretschmann being sensitive to the surface-near region and EIS to the whole system. For instance, metal oxidation and delamination processes can be difficult to distinguish by EIS, while on the other hand oxidation and hydration reactions on aluminiumcan be confirmed as IR bands at distinct positions. Delamination and swelling of a polymer both result in negative bands in an IR spectrum, but these processes may be distinguished by EIS as alterations in different frequency regions. While traditional chemical pre-treatments for enhanced hydrolytic stability perform excellent, they are being phased out from industrial applications due to environmental concerns and work health issues. Today there is an intense ongoing research regarding the mechanisms and performance of environmentally friendly pretreatments to develop systems of similar performance, and the analysis of the confined metal / polymer interface is crucial for this development. The capability of the integrated in situ ATR-FTIR Kretschmann and EIS set-up was therefore further applied to systems where a surface pre-treatment had been applied to the metal prior to the organic coating. Studies were first performed on vacuum-evaporated films of zinc treated with a titanium-based conversion coating and further coated with a UV-curing polymer. Alterations of the conversion layer could be detected upon exposure to the electrolyte. Also alkaline-cleaned aluminium coated with an amino-functional silane film and a thermo-curing epoxy top-coat was thoroughlycharacterized by both ATR-FTIR and IRRAS and further investigated upon exposure toelectrolyte and humid air. Changes at the hidden interface were detected upon thermal curingof the epoxy film and during exposure in electrolyte, and the in situ ATR-FTIR Kretschm annanalysis showed a high sensitivity towards alterations in the interfacial region. Complementary studies in the absence of metal could confirm a water uptake within the silane film and water-induced alterations of the siloxane network. / QC 20101222

This thesis describes work carried out on the research, development and implementation of new processes for the fabrication of surface plasmon waveguide biosensors. Fabrication of surface plasmon resonance (SPR) based waveguides embedded in a thick CYTOP cladding with the incorporation of fluidic channels was achieved with improved quality and operability compared to previous attempts. The fabrication flow was modified in key areas including lithography for feature definition, gold evaporation and the upper cladding deposition procedure. The combined result yielded devices with sharper resolution of waveguides, gold surfaces with minimal aberrations, reduced surface roughness and minimization of waveguide deformation due to reduction of solvent diffusion into the lower cladding. The fabricated waveguides consisted of a thin, 35 nm, patterned gold film, embedded in a thick, 18 µm, CYTOP fluoroploymer cladding. The gold devices were exposed by O2 plasma etching through the upper cladding to form fluidic channels for the facilitation of flow of an index matched sensing medium. Optical and physical characterization of devices revealed structures of significantly improved quality over previous attempts, rendering the platform competitive for biosensing applications.

The demand for hydrogen as a clean energy carrier has increased greatly. The Cu-Cl cycle is a promising thermochemical cycle that is currently being developed to be the large-scale method of hydrogen production. The lifetime of materials for the pipes transporting molten CuCl is an important parameter for an economic design of a commercial thermochemical Cu-Cl hydrogen plant. This research is an examination of candidate materials following an immersion test in molten CuCl at 500 °C for 100 h. Two alloys, Ni based super-alloy (Inconel 625) and super austenitic stainless steel (AL6XN) were selected as the base metal. There were two types of coating applied to improve the corrosion resistance of the base metals during molten CuCl exposure. A metallic of Diamalloy 4006 and two ceramic of yttria stabilized zirconia and alumina coatings were applied to the base metal using thermal spray methods. An immersion apparatus was designed and constructed to perform an immersion test that has a condition similar to those in a hydrogen plant. After the immersion test, the materials were evaluated using an electrochemical method in combination with ex-situ surface analysis. The surface condition including elemental composition, film structure and resistivity of the materials were examined and compared. The majority of the coatings were damaged and fell off. Cracks were found in the original coated specimens indicating the sample geometry may have affected the integrity of the sprayed coating. When the coating cracked, it provided a pathway for the molten CuCl to go under the coating and react with the surface underneath the coating. Copper deposits and iron chloride that were found on the sample surfaces suggest that there were corrosion reactions that involved the metal dissolution and reduction of copper during immersion test. The results also suggest that Inconel 625 performed better than stainless steel AL6XN. Both Diamalloy 4006 and YSZ (ZrO2 18TiO2 10Y2O3) coatings seemed to provide better protection to the underlying base metal than alumina (Al2O3 3TiO2) coating. / UOIT

The virtual worlds of Computer Graphics are populated by geometric objects, called models. Researchers have addressed the problem of synthesizing models automatically. Traditional modeling approaches often require a user to guide the synthesis process and to look after the geometry being synthesized, but user attention is expensive, and reducing user interaction is therefore desirable. I present a scheme for the automatic creation of geometry by deforming surfaces. My scheme includes a novel surface representation; it is an explicit representation consisting of points and edges, but it is not a traditional polygonal mesh. The novel surface representation is paired with a resampling policy to control the surface density and its evolution during deformation. The surface deforms with velocities assigned to its points through a set of deformation operators. Deformation operators avoid the manual computation and assignment of velocities, the operators allow a user to interactively assign velocities with minimal effort. Additionally, Petri nets are used to automatically deform a surface by mimicking a user assigning deformation operators. Furthermore, I present an algorithm to translate from the novel surface representations to a polygonal mesh. I demonstrate the utility of my model generation scheme with a gallery of models created automatically. The scheme's surface representation and resampling policy enables a surface to deform without requiring a user to control the deformation; self-intersections and hole creation are automatically prevented. The generated models show that my scheme is well suited to create organic-like models, whose surfaces have smooth transitions between surface features, but can also produce other kinds of models. My scheme allows a user to automatically generate varied instances of richly detailed models with minimal user interaction.

Interfacial tension provides valuable information about polymer processes such as foaming, particle (pigment) suspension, wetting, and blending. Among the methods commonly used to measure surface tension, drop shape methods entail several advantages such as simplicity and versatility. The profile of the drop, which is determined by the balance between gravity and surface forces, is easily defined. The surface tension is obtained from the profile of the drop. Recent progress in image analysis and data acquisition systems makes it possible to digitalize drop images directly using a video frame grabber with a digital camera. The digital signals are easily analyzed using different algorithms to determine the surface/interfacial tension from the drop profile. This study concentrates on one of the drop methods, the pendant drop method, which involves the determination of a drop profile of one dense liquid suspended in another liquid at mechanical equilibrium. Despite theoretical simplicity of using sessile and pendant drops for determining the surface tension of polymer melts, research in this area is limited because of the experimental difficulty associated with maintaining equilibrium of highly viscous melts. This paper examines the surface tension of polystyrene melts using Axisymmetric Drop Shape Analysis (ADSA) at high temperatures. This thesis focuses on attaining a stable pendant drop during experiments and modifying experimental designs. The method is verified by experiments in the air and nitrogen, where reproducibility tests and statistical analyses are performed. The surface tension of polystyrene (PS) that melts in supercritical carbon dioxide is obtained while the gas solubility is correlated with the surface tension value determined under various conditions. The Sanchez-Lacombe (S-L) equation of state (EOS) is applied to estimate the Pressure-Volume-Temperature (PVT) data of the PS/supercritical-carbon-dioxide mixtures, which gives density data. The relationship between surface tension and density is described by the empirical Macleod equation. To characterize the stability of pendant drops formed by the polymer melt, the Bond number is found to be useful; in particular, a stable pendant drop is obtained when the Bond number is between 0.4 and 0.8. This thesis presents experimental results of the surface tension of polystyrene in supercritical carbon dioxide, together with theoretical calculations for a corresponding system. The surface tension is determined by Axisymmetric Drop Shape Analysis-Profile (ADSA-P), where a high pressure and temperature cell is designed and constructed to facilitate the formation of a pendant drop of polystyrene melt. Self-consistent field theory (SCFT) calculations are applied to simulate the surface tension of a corresponding system, and a good agreement with the experiment is obtained. The physical mechanisms for three main experimental trends are explained using SCFT, and none of the explanations depend on the configurational entropy of the polymer constituents. These calculations therefore rationalize the use of simple liquid models for the quantitative prediction of surface tensions of polymers. As pressure and temperature increase, the surface tension of polystyrene decreases. A linear relationship is found between surface tension and temperature, and between surface tension and pressure; the rate of surface tension change with temperature is dependent on pressure. A linear relationship is found between surface tension and temperature, and between surface tension and pressure within a temperature range of 170-210C and a pressure range of 500-2,000 psi. Two monodisperse polystyrenes of Mw ~ 100,000 and Mw ~400,000 and a polydisperse polystyrene were investigated to show the temperature and pressure effect on the surface tension in supercritical nitrogen. Regardless of the molecular weight and polydispersity, the surface tension of polystyrenes decreases as the pressure and temperature increase. Monodisperse polystyrene of a higher molecular weight has a higher surface tension by 6-9 mJ/m2 at each experimental condition. The surface tension dependence on temperature and on pressure is more significant for the higher molecular weight polystyrene; the surface tension has been varied more in the higher molecular weight polystyrene than in the lower molecular weigh polystyrene. For a polydisperse polystyrene, high surface tension values seem to be determined predominantly by its high molecular weight portion of polystyrene molecules. An empirical equation was generated to relate surface tension to the density difference between the polymer and supercritical nitrogen. This research should have implications in understanding polymer foaming processes and have application in various polymer engineering fields including polymer characterizations, polymer synthesis, and surface modifications.

This work approaches the problem of triangulating algebraic curves/surfaces with a subdivision-style algorithm using A-Patches. An implicit algebraic curve is converted from the monomial basis to the bivariate Bernstein-Bezier basis while implicit algebraic surfaces are converted to the trivariate Bernstein basis. The basis is then used to determine the scalar coefficients of the A-patch, which are used to find whether or not the patch contains a separation layer of coefficients. Those that have such a separation have only a single sheet of the surface passing through the domain while one that has all positive or negative coefficients does not contain a zero-set of the surface. Ambiguous cases are resolved by subdividing the structure into a set of smaller patches and repeating the algorithm. Using A-patches to generate a tessellation of the surface has potential advantages by reducing the amount of subdivision required compared to other subdivision algorithms and guarantees a single-sheeted surface passing through it. This revelation allows the tessellation of surfaces with acute features and perturbed features in greater accuracy.