Metalle werden oft während ihrer Anwendung korrosiven Bedingungen ausgesetzt, was ihre Alterungsbeständigkeit reduziert. Deswegen werden korrosionsanfällige Metalle, wie Aluminiumlegierungen mit Schutzbeschichtungen versehen, um den Korrosionsprozess aktiv oder passiv zu verhindern. Die klassischen Schutzbeschichtungen funktionieren als physikalische Barriere zwischen Metall und korrosiver Umgebung und bieten einen passiven Korrosionsschutz nur, wenn sie unbeschädigt sind. Im Gegensatz dazu kann die Korrosion auch im Fall einer Beschädigung mittels aktiver Schutzbeschichtungen gehemmt werden. Chromathaltige Beschichtungen bieten heutzutage den besten aktiven Korrosionsschutz für Aluminiumlegierungen. Aufgrund ihrer Giftigkeit wurden diese weltweit verboten und müssen durch neue umweltfreundliche Schutzbeschichtungen ersetzt werden. Ein potentieller Ersatz sind Schutzbeschichtungen mit integrierten Nano- und Mikrobehältern, die mit ungiftigem Inhibitor gefüllt sind. In dieser Arbeit werden die Entwicklung und Optimierung solcher aktiver Schutzbeschichtungen für die industriell wichtige Aluminiumlegierung AA2024-T3 dargestellt Mesoporöse Silika-Behälter wurden mit dem ungiftigen Inhibitor (2-Mercaptobenzothiazol) beladen und dann in die Matrix anorganischer (SiOx/ZrOx) oder organischer (wasserbasiert) Schichten dispergiert. Zwei Sorten von Silika-Behältern mit unterschiedlichen Größen (d ≈ 80 and 700 nm) wurden verwendet. Diese haben eine große spezifische Oberfläche (≈ 1000 m² g-1), eine enge Porengrößenverteilung mit mittlerer Porenweite ≈ 3 nm und ein großes Porenvolumen (≈ 1 mL g-1). Dank dieser Eigenschaften können große Inhibitormengen im Behälterinneren adsorbiert und gehalten werden. Die Inhibitormoleküle werden bei korrosionsbedingter Erhöhung des pH-Wertes gelöst und freigegeben. Die Konzentration, Position und Größe der integrierten Behälter wurden variiert um die besten Bedingungen für einen optimalen Korrosionsschutz zu bestimmen. Es wurde festgestellt, dass eine gute Korrosionsschutzleistung durch einen Kompromiss zwischen ausreichender Inhibitormenge und guten Barriereeigenschaften hervorgerufen wird. Diese Studie erweitert das Wissen über die wichtigsten Faktoren, die den Korrosionsschutz beeinflussen. Somit wurde die Entwicklung effizienter, aktiver Schutzbeschichtungen ermöglicht, die auf mit Inhibitor beladenen Behältern basieren. / Metals are often used in environments that are conducive to corrosion, which leads to a reduction in their mechanical properties and durability. Coatings are applied to corrosion-prone metals such as aluminum alloys to inhibit the destructive surface process of corrosion in a passive or active way. Standard anticorrosive coatings function as a physical barrier between the material and the corrosive environment and provide passive protection only when intact. In contrast, active protection prevents or slows down corrosion even when the main barrier is damaged. The most effective industrially used active corrosion inhibition for aluminum alloys is provided by chromate conversion coatings. However, their toxicity and worldwide restriction provoke an urgent need for finding environmentally friendly corrosion preventing systems. A promising approach to replace the toxic chromate coatings is to embed particles containing nontoxic inhibitor in a passive coating matrix. This work presents the development and optimization of effective anticorrosive coatings for the industrially important aluminum alloy, AA2024-T3 using this approach. The protective coatings were prepared by dispersing mesoporous silica containers, loaded with the nontoxic corrosion inhibitor 2-mercaptobenzothiazole, in a passive sol-gel (SiOx/ZrOx) or organic water-based layer. Two types of porous silica containers with different sizes (d ≈ 80 and 700 nm, respectively) were investigated. The studied robust containers exhibit high surface area (≈ 1000 m² g-1), narrow pore size distribution (dpore ≈ 3 nm) and large pore volume (≈ 1 mL g-1) as determined by N2 sorption measurements. These properties favored the subsequent adsorption and storage of a relatively large amount of inhibitor as well as its release in response to pH changes induced by the corrosion process. The concentration, position and size of the embedded containers were varied to ascertain the optimum conditions for overall anticorrosion performance. Attaining high anticorrosion efficiency was found to require a compromise between delivering an optimal amount of corrosion inhibitor and preserving the coating barrier properties. This study broadens the knowledge about the main factors influencing the coating anticorrosion efficiency and assists the development of optimum active anticorrosive coatings doped with inhibitor loaded containers.

Tato práce se zabývá studiem termooxidační stability kompozitů polymethylmethakrylátu (PMMA) plněného mikro a nanočásticemi siliky. V připravených vzorcích byly použity různé objemové zlomky a různé velikosti částic siliky. Studium stability bylo prováděno pomocí termogravimetrie, která umožňuje simulovat podmínky termooxidační degradace. Indukční perioda byla stanovena za použití různých rychlostí ohřevu a aplikací izokonverzních metod. Závislosti teplot degradací na rychlostech ohřevu sloužily pro určení parametrů odvozených ze čtyř různých teplotních funkcí, které dovolují předpověď stability materiálu (indukční periody) při zvoleném rozsahu teplot. Zjištěné výsledky ukazují, že větší částice siliky snižuji stabilitu PMMA, zatímco nanočástice v nízkých koncentracích ji nijak neovlivňují.

The aim of this work is to develope fast-setting geopolymeric binders applicable in the chemical wall clamp. This clamping systems are big trend because of easy application, ability to transfer big forces and short setting time. Binders of this systems are based on polymeric resin. Their raw materials are expensive, toxic and flammable substances. Based on this consideration an anorganic fast-setting geopolymeric binder was developed. This binders consist of mixture of metakaolin and precipitated silica activated by potassium hydroxide. Binder were characterized by suitable analytic methods (XRD, SEM, DTA). The results of this metods were used for optimalization of binder properties.

Ziel der Diplomarbeit ist es, eine Dispersion aus Monomer und Silika-Partikeln auf ein festes Substrat aufzutragen, die so erhaltenen Versuchsträger mit dem Monomer/Partikel-Film (Modell Monomer/Partikel/festes Substrat) anschließend mit dem Rasterkraftmikroskop abzubilden und anschließend hinsichtlich der Oberflächenkrümmung und dem Kontaktwinkel zu untersuchen. Durch die Kontaktwinkelmessung am Dreiphasenpunkt soll eine erste Charakterisierung der kapillaren Oberfläche erfolgen, die jedoch nur ein Teilschritt bis zur vollständigen Optimierung von durch partikel-assistierte Benetzung hergestellte poröse Membranen ist.

Nanomaterials have attracted considerable attention during the past decades due to their unique and fascinating properties. However, this class of materials is not an invention of modern age. People have been using nanomaterials for centuries, although unwittingly. Probably the most famous example for the usage of nanomaterials in ancient times is the Lycurgus Cup, a Roman glass cage cup created in the 4th century which changes the colour of its glass from green to ruby depending on the illumination conditions. The foundation for the development of the field of nanotechnology was laid by the speech of Feynman “There is plenty of room at the bottom” in 1959, in which he spoke about the principles of miniaturisation as low as to the atomic level. Today, modern nanotechnology made it its business to purposefully develop and synthesise nanomaterials as well as to face their applications in various fields, such as microelectronics, catalysis or biomedicine. However, the term “nanomaterials” does not solely involve the nanoparticulate units itself, but also their arrangement into two- or three-dimensional structures. Thereby, the maintenance of the nanoscale properties is one of the main challenges. This task was focussed by this work implied the preparation and macroscale arrangement of fluorescent QDs while preserving their optical properties. The main achievement of this work was the development of a novel aerogel material with non-quenching PL behaviour by using silica coated QDs as nanoparticulate building units. In comparison to other monolithic silica-QD structures or aerogels from pure QDs, a defined and controllable distance between the fluorescent QDs is provided in these structures by the silica shell. The spacing was shown to efficiently disable energy transfers so that no spectral shifts, lifetime shortening or PL QY losses are observed during the colloid to gel transition. The silica shell, established by a standard reverse microemulsion approach, was found to exhibit a certain porosity, which was proven by gas adsorption measurements. Existing cavities in the micro- and mesoporous range were found to allow small species such as metal ions to pass through the shell and interact with the QD core causing a detectable change of the PL intensity, which makes these materials suitable for future sensing applications. The gel preparation was based on a metal ion assisted complexation approach, which requires tetrazole functionalisation of the nanoparticulate building units. A major development in this work that permitted this gelation approach for silica-QDs was the development of a novel tetrazole-silane ligand. TMSPAMTz was specifically designed to bind to the silica surface of silica-QDs in aqueous solution and was prepared by a covalent coupling of an alkyl chained silane with a 5-subsituted tetrazole ring. Network formation is subsequently achieved by the interconnection of negatively charged tetrazole rings with metal ions, which allows for a broad spectrum of aerogel materials from different NP species as well as their mixtures as long as tetrazole capping is provided. Considering this diversity and the disabling of energy transfers, straightforward colour tuning was demonstrated herein by mixing differently emitting silica-QD species which gives great prospects for lighting applications. Furthermore, the possibility of plasmon enhanced emission was presented for mixed Au NP/silica-QD gels. With respect to future sensing applications, thin porous films from silica-QDs gels were prepared, which showed a promising concentration dependant PL quenching for the model analyst hydrogen peroxide. However, the film reproducibility of the applied drop-cast coating method was insufficient. As a suggestion to this, a LbL method was presented, wherein a gel is subsequently grown with the metal ion assisted complexation approach. In addition to the tetrazole ligands on the NP surface, tetrazole-silane ligands were used in this approach to functionalise the glass substrate surface. By this, homogeneous gel films of distinct thickness can be grown while the use of organic polymers can be completely avoided. Besides the preparation of NP assemblies, standard Cd-based QD materials as well as Au NPs of different sizes and shape, recent progresses in the synthesis of InP-based QDs were presented in this work. A thorough investigation and understanding of the growth influencing parameters allowed for the establishment of preparation routes for In(Zn)P/GaP/ZnS core/shell/shell QDs with emission wavelengths tuneable within a large range from 500 to 650 nm, narrow peak widths of 45 to 70 nm and PL QYs up to 60%. Successful incorporation of these QDs into salt matrices was further demonstrated. The resulting composite materials are very photostable and suitable as colour conversion materials for solid state lighting, as was clearly pointed out by a self-prepared WLED that met the standard commercial LEDs.

Thermoporosimetry is a technique to determine small pore sizes based on melting and crystallization point depression. The temperature shift was measured by Differential Scanning Calorimetry (DSC). Development of thermoporosimetry was carried out on silica with a well-characterized narrow pore size distribution. Several parameters were studied, which a have a direct influence on melting and crystallization point depression (for example: a quality of the solvent, filling the pores with the solvent, time and frequency of centrifuging, superfluous solvent removal conditions, etc.). The optimum conditions for the thermoporosimetry method were developed using high porosity silica. The optimized experimental conditions found for silica were applied to polypropylene powder with much lower porosity. Several polypropylene powders were synthesized using different polymerization catalysts and their porosity determined. Polymer powder morphology and structure was characterized by standard methods. Powder porosity obtained by thermoporometry, gas sorption, and BET methods was compared.

Nanomaterials have attracted considerable attention during the past decades due to their unique and fascinating properties. However, this class of materials is not an invention of modern age. People have been using nanomaterials for centuries, although unwittingly. Probably the most famous example for the usage of nanomaterials in ancient times is the Lycurgus Cup, a Roman glass cage cup created in the 4th century which changes the colour of its glass from green to ruby depending on the illumination conditions. The foundation for the development of the field of nanotechnology was laid by the speech of Feynman “There is plenty of room at the bottom” in 1959, in which he spoke about the principles of miniaturisation as low as to the atomic level. Today, modern nanotechnology made it its business to purposefully develop and synthesise nanomaterials as well as to face their applications in various fields, such as microelectronics, catalysis or biomedicine. However, the term “nanomaterials” does not solely involve the nanoparticulate units itself, but also their arrangement into two- or three-dimensional structures. Thereby, the maintenance of the nanoscale properties is one of the main challenges. This task was focussed by this work implied the preparation and macroscale arrangement of fluorescent QDs while preserving their optical properties. The main achievement of this work was the development of a novel aerogel material with non-quenching PL behaviour by using silica coated QDs as nanoparticulate building units. In comparison to other monolithic silica-QD structures or aerogels from pure QDs, a defined and controllable distance between the fluorescent QDs is provided in these structures by the silica shell. The spacing was shown to efficiently disable energy transfers so that no spectral shifts, lifetime shortening or PL QY losses are observed during the colloid to gel transition. The silica shell, established by a standard reverse microemulsion approach, was found to exhibit a certain porosity, which was proven by gas adsorption measurements. Existing cavities in the micro- and mesoporous range were found to allow small species such as metal ions to pass through the shell and interact with the QD core causing a detectable change of the PL intensity, which makes these materials suitable for future sensing applications. The gel preparation was based on a metal ion assisted complexation approach, which requires tetrazole functionalisation of the nanoparticulate building units. A major development in this work that permitted this gelation approach for silica-QDs was the development of a novel tetrazole-silane ligand. TMSPAMTz was specifically designed to bind to the silica surface of silica-QDs in aqueous solution and was prepared by a covalent coupling of an alkyl chained silane with a 5-subsituted tetrazole ring. Network formation is subsequently achieved by the interconnection of negatively charged tetrazole rings with metal ions, which allows for a broad spectrum of aerogel materials from different NP species as well as their mixtures as long as tetrazole capping is provided. Considering this diversity and the disabling of energy transfers, straightforward colour tuning was demonstrated herein by mixing differently emitting silica-QD species which gives great prospects for lighting applications. Furthermore, the possibility of plasmon enhanced emission was presented for mixed Au NP/silica-QD gels. With respect to future sensing applications, thin porous films from silica-QDs gels were prepared, which showed a promising concentration dependant PL quenching for the model analyst hydrogen peroxide. However, the film reproducibility of the applied drop-cast coating method was insufficient. As a suggestion to this, a LbL method was presented, wherein a gel is subsequently grown with the metal ion assisted complexation approach. In addition to the tetrazole ligands on the NP surface, tetrazole-silane ligands were used in this approach to functionalise the glass substrate surface. By this, homogeneous gel films of distinct thickness can be grown while the use of organic polymers can be completely avoided. Besides the preparation of NP assemblies, standard Cd-based QD materials as well as Au NPs of different sizes and shape, recent progresses in the synthesis of InP-based QDs were presented in this work. A thorough investigation and understanding of the growth influencing parameters allowed for the establishment of preparation routes for In(Zn)P/GaP/ZnS core/shell/shell QDs with emission wavelengths tuneable within a large range from 500 to 650 nm, narrow peak widths of 45 to 70 nm and PL QYs up to 60%. Successful incorporation of these QDs into salt matrices was further demonstrated. The resulting composite materials are very photostable and suitable as colour conversion materials for solid state lighting, as was clearly pointed out by a self-prepared WLED that met the standard commercial LEDs.

Membrane-based filtration and separation processes are widely used in various fields, such as for clean drinking water, food, dairy industry, medical, biotechnology, and environmental applications. Providing clean and safe drinking water has been regarded as one of the global biggest challenges because of increasing world population, impacts of climate changes, increased wastewater production, and increased contamination of surface and groundwater. The most important technologies contributing substantially in this field are based on pressure-driven membrane technologies such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Recently, in situ synthesis of nanoparticles based on molecular level design and tailoring in the membrane matrix have been reported to prepare next generation nano-enhanced membranes. In this work similar technique was utilized to construct PSF-Silica nanocomposite membranes in which hydrolysis and condensation of silica precursor (TEOS, APTES, and TPAPS) and phase inversion of polymer film was achieved simultaneously in one step under acidic condition. This unique process has led to the formation of extremely small silica nanoparticles with high dispersion in every region of the membrane. Such type of distribution of silica nanoparticles is very difficult to achieve using conventional silica nanoparticle blending with polymer solution. The prepared membranes were extensively characterized for their morphology, surface properties, nanoparticle distribution, fouling and permeation properties. Finally, the membranes were tested with rejection experiments with protein and dye solutions to assess their usefulness for water filtration and separation applications. The silica nanoparticles were mostly generated during the phase inversion under acidic condition by hydrolysis and polycondensation reaction of silica precursors mixed with PSF solution. The properties and structure of membranes were characterized by different analytic and physicochemical techniques. The prepared membranes exhibit an asymmetric nature with a dense skin layer, followed by finger-like porous structure at the bottom. The microscopic and elemental analysis confirmed the presence and homogeneous distribution of nanoscopic small silica particles throughout the membrane matrix. Hydrophilic SiO2, SiO2-NH2, SO2-NH-SO3H nanoparticles were respectively formed in situ within PSF membrane matrix during the phase inversion under acidic condition by hydrolysis and polycondensation reaction of corresponding silica precursors mixed with PSF solution. Because the nanosize and good distribution of the pores, the presence and well distribution of silica nanoparticles, the presence and exposure of the hydrophilic charged functional groups form a hydrate layer on the membranes and provide hydration repulsion and electrostatic repulsion against solutes from feed under aqueous medium, the PSF-TEOS, PSF-APTES, PSF-TPAPS membranes respectively with SiO2, SiO2-NH2, and SO2-NH-SO3H nanoparticles exhibited high hydrophilicity, stability, water permeation, rejection, and antifouling performance as compared to the neat PSF membrane for water purification application. The overall membrane properties were highly dependent on the concentration of the silica nanoparticles and can be tuned by adjusting the concentration of initial silica precursors during membrane formation. The low protein fouling, high water permeation, protein rejection, and flux recovery results make those membranes attractive for separation and filtration applications. Thus, the prepared membranes can be used in different applications ranging from separation of biomolecules, desalination/purification of water, and for other charge and size-based separation processes.

Ziel der Diplomarbeit ist es, eine Dispersion aus Monomer und Silika-Partikeln auf ein festes Substrat aufzutragen, die so erhaltenen Versuchsträger mit dem Monomer/Partikel-Film (Modell Monomer/Partikel/festes Substrat) anschließend mit dem Rasterkraftmikroskop abzubilden und anschließend hinsichtlich der Oberflächenkrümmung und dem Kontaktwinkel zu untersuchen. Durch die Kontaktwinkelmessung am Dreiphasenpunkt soll eine erste Charakterisierung der kapillaren Oberfläche erfolgen, die jedoch nur ein Teilschritt bis zur vollständigen Optimierung von durch partikel-assistierte Benetzung hergestellte poröse Membranen ist.

Concrete manufacturers claim that using substitute like blast furnace slag, fly ash and silica reduces the climate impact when used as a substitute for cement. Reducing climate emissions is an important topic for companies that currently produce concrete to achieve a sustainable society. The results have been collected by conducting interviews withexperts and sending out a questionnaire survey to concrete companies as well as some assessment through possible calculations that are linked to the survey results. The purpose of the survey is to find out the different substitutes used in Sweden and which substitutes may be conceivable for the future and to assess the development work for these different substitutes. The study shall provide relevant information about these different substitutes and show what effects are brought to the climate when the substitutes are used. The aim of the study is to increase understanding of current and future concrete and how these various substitutes can be useful in the future in the manufacture of concrete. Blast furnace slag, fly ash and silica are three different substitutes used as substitutes for cement. The most common substitute that is available and useful in Sweden is blast furnace slag, which means less climate impact. Conclusions drawn by the study are that these various substitutes contribute to reduced climate impact when used with cement and that substitutes are a temporary solution, meanwhile the real problem is to find new products as alternatives to limestone in cement production.