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Coating colors are applied to the base paper in order to maximize the performance of the end product. Coating colors are complex colloidal systems, mainly consisting of water, binders, and pigments. To understand the behavior of colloidal suspensions, an understanding of the interactions between its components is essential.

In this thesis, I describe experiments that were designed to provide a better understanding of polymer diffusion during latex film formation. This step leads to the improvement of film mechanical properties. Polymer diffusion in these films was monitored by fluorescence resonance energy transfer. Current paint formulations contain Volatile Organic Compounds (VOCs) as plasticizers to facilitate polymer diffusion. The drawback of this technology is the release of VOCs to the atmosphere. VOCs are deleterious to the environment and contribute to smog and ground level ozone formation. The propensity of water, an indispensible part of any latex dispersion, to promote polymer diffusion was studied. Copolymers of poly (butyl acrylate-co-methyl methacrylate) and poly(ethylhexyl acrylate-co-tertiary butyl methacrylate) with similar glass transition temperatures but different hydrophobicity were compared. Polymer diffusion was monitored for films aged at different relative humidities. Water absorbed by the hydrophobic copolymer film was less efficient in promoting polymer diffusion than in the hydrophilic polymer. Only the fraction of water which is molecularly dissolved in the film participate actively in plasticization. Although water has low solubility in most latex polymers, molecularly dissolved water is more efficient than many traditional plasticizers. The possibility of modifying film formation behavior of acrylic dispersions with oligomers was studied by synthesizing hybrid polymer particles consisting of a high molecular weigh (high-M) polymer and an oligomer with the same composition. Oligomers with lower molecular weight are more efficient as diffusion promoters and have less deleterious effect on high-M polymer viscosity. A different set of hybrid particles were prepared in which the oligomer contained methacrylic acid units. The composition of the oligomer was tuned to be miscible with the high-M polymer when the acid groups were protonated but to phase separate when the acid groups were deprotonated. At basic pH, these particles adopt a core-shell morphology, with a shell rich in neutralized oligomers. After film formation, the oligomer shell retarded polymer diffusion. This retardation is expected to expand the time window during which the paint surface can be altered without leaving brush marks (open time). Short open time is a pressing problem in current technology.

In this thesis, I describe experiments that were designed to provide a better understanding of polymer diffusion during latex film formation. This step leads to the improvement of film mechanical properties. Polymer diffusion in these films was monitored by fluorescence resonance energy transfer. Current paint formulations contain Volatile Organic Compounds (VOCs) as plasticizers to facilitate polymer diffusion. The drawback of this technology is the release of VOCs to the atmosphere. VOCs are deleterious to the environment and contribute to smog and ground level ozone formation. The propensity of water, an indispensible part of any latex dispersion, to promote polymer diffusion was studied. Copolymers of poly (butyl acrylate-co-methyl methacrylate) and poly(ethylhexyl acrylate-co-tertiary butyl methacrylate) with similar glass transition temperatures but different hydrophobicity were compared. Polymer diffusion was monitored for films aged at different relative humidities. Water absorbed by the hydrophobic copolymer film was less efficient in promoting polymer diffusion than in the hydrophilic polymer. Only the fraction of water which is molecularly dissolved in the film participate actively in plasticization. Although water has low solubility in most latex polymers, molecularly dissolved water is more efficient than many traditional plasticizers. The possibility of modifying film formation behavior of acrylic dispersions with oligomers was studied by synthesizing hybrid polymer particles consisting of a high molecular weigh (high-M) polymer and an oligomer with the same composition. Oligomers with lower molecular weight are more efficient as diffusion promoters and have less deleterious effect on high-M polymer viscosity. A different set of hybrid particles were prepared in which the oligomer contained methacrylic acid units. The composition of the oligomer was tuned to be miscible with the high-M polymer when the acid groups were protonated but to phase separate when the acid groups were deprotonated. At basic pH, these particles adopt a core-shell morphology, with a shell rich in neutralized oligomers. After film formation, the oligomer shell retarded polymer diffusion. This retardation is expected to expand the time window during which the paint surface can be altered without leaving brush marks (open time). Short open time is a pressing problem in current technology.

Das Begriffsfeld zu Transgender und verwandten Begriffen ist stark ausdifferenziert. Es soll hier nun nicht der Versuch unternommen werden, einen umfassenden Überblick über die komplexe Transgender-Thematik zu geben. Die Frage ist vielmehr, wie eine Pädagogik der Vielfalt am Beispiel von Transgender auch in Schulen umgesetzt werden kann und Schülerinnen und Schüler für dieses Thema sensibilisiert werden können. Für eine pädagogische Auseinandersetzung eignen sich insbesondere Spielfilme – und mittlerweile gibt es eine ganze Reihe geeigneter Filme zum Thema Transgender. Der Film „Transamerica“, den Hamisch in ihrem Beitrag analysiert, verdeutlicht vor allem die Identitätsherausforderungen, denen sich die Protagonistin des Films stellen muss. Dies ermöglicht einen pädagogisch-didaktischen Zugang zum Thema, der nicht von normativen Positionen ausgeht, die die Schülerinnen und Schüler mitbringen, sondern zur Reflexion über die eigene Identität anregt.

Die Auseinandersetzung mit der Transgenderthematik auf politischer, gesellschaftlicher und kultureller Ebene wird immer wieder auch medial verhandelt. Um Verständnis und Akzeptanz zu fördern und Diskriminierung und Transphobie entgegenzuwirken, gilt es, das Thema auch pädagogisch aufzuarbeiten. Die Thematik wird aus medizinischer, gesellschaftlicher und rechtlicher Perspektive dargelegt, um anschließend aufzuzeigen, inwiefern sie in der Lebenswelt von Jugendlichen und in der Schule vertreten ist. Dabei wird offensichtlich, dass hinsichtlich pädagogischer Ansätze in der Schule Nachholbedarf besteht. Um Jugendliche für die Identitätsherausforderungen von Transgendern zu sensibilisieren, eignet sich der US-amerikanische Spielfilm „Trans­america“, welcher hier insbesondere im Hinblick auf die Identitätsherausforderungen der Hauptcharaktere medienpädagogisch analysiert wird. In der abschließenden medienpädagogischen Einschätzung wird erörtert, inwiefern der Film auch im Unterricht eingesetzt werden kann.

The aim of this diploma thesis is to describe mechanisms involved in a lubricant film formation in textured conformal contacts. For exploring of the lubricant film formation, the method of optical interferometry is implemented on a pin-on-disc tribometer. That allows to study an influence of a texture on lubricant film thickness and coefficient of friction of textured samples. These samples have different parameters of a texture. On the basis of these effects and the visual image of the contact, the flow of lubricant in the contact area is described. Shallow dimples lead to larger film thickness in elasto-hydrodynamic lubrication regime. They act like a lubricant reservoir. Deep dimples positively affect film thickness in hydrodynamic lubrication regime, where the effect of shallow dimples descend. During experiments, the formation of a cavitation is observed. The cavitation causes a starvation of dimples in many cases. This leads to reducing of the lubricant film thickness. This effect can be eliminated by appropriate parameters of texture in operational conditions of elements.

Die Auseinandersetzung mit der Transgenderthematik auf politischer, gesellschaftlicher und kultureller Ebene wird immer wieder auch medial verhandelt. Um Verständnis und Akzeptanz zu fördern und Diskriminierung und Transphobie entgegenzuwirken, gilt es, das Thema auch pädagogisch aufzuarbeiten. Die Thematik wird aus medizinischer, gesellschaftlicher und rechtlicher Perspektive dargelegt, um anschließend aufzuzeigen, inwiefern sie in der Lebenswelt von Jugendlichen und in der Schule vertreten ist. Dabei wird offensichtlich, dass hinsichtlich pädagogischer Ansätze in der Schule Nachholbedarf besteht. Um Jugendliche für die Identitätsherausforderungen von Transgendern zu sensibilisieren, eignet sich der US-amerikanische Spielfilm „Trans­america“, welcher hier insbesondere im Hinblick auf die Identitätsherausforderungen der Hauptcharaktere medienpädagogisch analysiert wird. In der abschließenden medienpädagogischen Einschätzung wird erörtert, inwiefern der Film auch im Unterricht eingesetzt werden kann.

<p>In industrial use of paint systems a swift processing is crucial. Another very important issue is to improve the quality of the final coating. This report investigates the film formation process of powder coatings, specially the spreading of individual powder particles. The obtained results can be used to understand and control the film formation process. In this way the desired levelling can be achieved and thus the desired gloss or other surface characteristics that may be required. This means that the method could be used when evaluating different polymer and additive combinations that could be used to change film formation behaviour or curing time for powder coating systems to suit various substrates. It makes it possible to avoid and minimize different surface defects as orange peel or cratering in the powder coated film.</p><p>We used a reflection optical microscope to better understand the film formation process and especially the spreading of a powder melt on surfaces with various surface energies. The obtained data were: the particle diameter, the area, area ratio and the contact angle of the powder particle as a function of time and temperature. This information can be used to derive the surface tension of any powder melt.</p><p>In this report we evaluate the dependencies of temperature, heat rate and surface energy for powder coatings on different substrates. The method provides information that can be used to optimize the film formation of a specific powder coating/substrate combination. This method can be used to evaluate the powder spreading and levelling on different substrates from a surface tension point of view.</p><p>We found, as expected, that the powder flows out on a hydrophilic surface and is inhibited by a hydrophobic. The increase of the area ratio on a hydrophilic surface was about five times as the initial area coverage and on a hydrophobic surface only two times the initial area coverage. The contact angle between the melted powder particle on the different surface types could be calculated. The melt surface tension could be calculated since three substrates surfaces with various surface energies were used. The melt surface tension was found to be about 18.5 mN/m.</p> / <p>Sammanfattning</p><p>Vid industriell användning av ett färgsystem är det viktigt med en snabb och smidig målningsprocess. En viktig del är att förbättra kvaliteten på den färdiga ytan. Denna rapport undersöker filmbildningsprocessen för pulverfärg, närmare bestämt spridningen av individuella pulverpartiklar. Resultaten från utvärderingen av denna metod kan användas för att bättre förstå och få kontroll över filmbildningsprocessen. Med denna undersökningsmetod kan den önskade utslätningen uppnås och därmed den önskade glansen eller annan yteffekt som kan vara önskvärd.</p><p>Metoden kan användas för att utvärdera olika polymer- och additivkombinationer som kan användas för att ändra filmbildningens uppförande eller bestämma härdningstiden för en pulverfärg att passa ett visst substrat. Metoden gör det möjligt att förhindra och minska olika ytdefekter såsom apelsinskals- eller kratereffekter i pulverfärgens yta.</p><p>Ett optiskt reflectionsmikroskop användes för att bättre kunna förstå filmbildningsprocessen och särskilt spridningen av smält pulver på substrat med olika ytenergier. De mätdata vi fick var partikeldiameter, area, areaförändring och kontaktvinkeln för pulverpartiklar som funktion av tid och temperatur. Ur denna information kunde pulversmältans ytenergier härledas.</p><p>I denna rapport utvärderas pulvrets beroende av temperatur, uppvärmning och ytenergi på olika substrat. Denna metod ger information som kan användas för att optimera filmbildningen av en specifik kombination av pulverfärg och substrat. Denna metod kan också användas för att utvärdera pulverspridning och utjämning av färgfilmen på olika substrat med avseende på ytenergierna.</p><p>Som förväntat flyter pulvret ut på hydrofila ytor och utflytningen ändras på en hydrofob yta. På en hydrofil yta sprider sig partikeln till fem gånger den ursprungliga arean över substratet och motsvarande två gånger för en hydrofob yta. Kontaktvinkeln mellan en smält pulverpartikel på olika sorters substrat från utförda mätningar beräknas utifrån utförda mätningar. Kontaktvinklar mellan pulver och olika substrat kan användas för att beräkna smältans ytspänning. Smältans ytspänning kan beräknas då experiment gjorts på tre sorters ytor med olika kända ytenergier. Smältans ytspänning var 18,5 mN/m.</p><p>Slutsatsen är att det går att observera och utvärdera resultaten av utsmältningsförloppet för pulverfärg med denna metod.</p>

Master of Science / Department of Chemistry / Daniel A. Higgins / Three water-soluble perylene diimides (PDIs) were investigated to examine differences in their thin film forming properties. The PDI thin films investigated in this thesis are formed in an electrostatic-self-assembled (ESA) layer-by-layer (LBL) process by the use of a dip coater. The three PDIs employed are sodium bis (sulfonatopropyl) perylene diimide (PDISO[subscript]3[superscript]2-), bis (trimethylammonioethyl) perylene diimide diiodide (PDIDI[superscript]2+), and N-(butoxypropyl)-N'-(2-(N,N,N-trimethylammonio)-ethyl) perylene-3,4,9,10-tetracarboxylic diimide iodide (C[subscript]7OPDI[superscript]+). Thin films were made by alternately depositing the PDIs with counter polyelectrolyte (PEs). The PEs employed were poly(diallyldimethylammonium chloride) (PDDA[superscript]+) and poly(acrylic acid) (PA[superscript]-), depending on the charge of the PDI. PDIs were determined to be aggregated in all three PDI precursor solutions. The fraction of PDI aggregated in each was found to be 0.972, 0.903, and 0.993, for the PDISO[subscript]3[superscript]2-, PDIDI[superscript]2+, and C[subscript]7OPDI[superscript]+, respectively. The C[superscript]7OPDI[superscript]+ solution was the most aggregated only having one charge group, which makes it more hydrophobic. Thin films prepared from the solutions all displayed an absorbance spectrum similar to the aggregated form. All the composites displayed linear growth in film thickness and fiber width with bilayer number. However, the three composites gave unique surface morphologies. The PDISO[subscript]3[supercript]2-[dot in middle of line]PDDA+ composite was found to incorporate highly curled intertwined fibers compared to the PDIDI[superscript]2+[dot in middle of line]PA[superscript]- composite, where the fibers were not intertwined. The fiber structure was found to change after 15 bilayers. This change in morphology was attributed to the fibers grafting together and overlapping causing the loss of original fiber structure. The two symmetric composites differed in the film thickness with the PDISO[subscript]3[superscript]2-[dot in middle of line]PDDA[superscript]+ being thicker than the PDIDI[superscript]2+[dot in middle of line]PA[superscript]- composite. This was attributed to the molecular weights (MW) of the polyelectrolytes investigated during thin film deposition, with the PDDA[superscript]+ having a much higher MW. C[subscript]7OPDI[superscript]+[dot in middle of line]PA[superscript]- thin film composite had a film thickness approximately equal to the PDISO[subscript]3[superscript]2-[dot in middle of line]PDDA[superscript]+ composite, indicating precursor aggregation also influences deposition rate. The C[subscript]7OPDI[superscript]+[dot in middle of line]PA[superscript]- composite incorporated wavy thin fibers that appeared aligned in the dipping direction. This alignment was visible for bulk samples in UV-vis absorption dichroism studies. The alignment was parallel to the dipping direction of the substrate.