Då marina enheter numera deltar i internationella missioner, kommer den nya miljön som enheterna opererar i att påverka bland annat deras sensorer. Den här studien avhandlar några av de nu framtagna självsanerande ytbeläggningarna och ger en presentation av hur de fungerar på några marina elektrooptiska sensorers yttersta linser. Studien försöker ge svar på ytbeläggningarnas transmittans och hur effektivt de kan sanera bort oönskade saltlager tillsammans med andra nedsmutsande partiklar från sensorlinserna samt den militära nyttan av att använda självsanerande ytbeläggning. / This study deals with now developed self-cleaning coatings and gives a presentation of how they work on some electro-optical sensor lenses used in the navy. The study also examines the coatings transmittance and how efficient they can clean the sensor lenses from undesired salt layers and other soiling particles. After the introduction the study presents basic facts of the chosen sensors, nanotechnology, surface wettability and also salts and salinity. Thereafter the study describes current nano-research on self-cleaning coatings and possible results there of, when the coatings are applied on the different sensors. In the study I give my opinion of the military benefit of using self-cleaning coatings, which from a general point of view is that there mostly are positive effects using such a coating, in a technical perspective. The study ends with conclusions that there are self-cleaning coatings based on TiO2-nanoparticles which can transmit within the visual spectra and also can clean undesired soiling particles. But can not confirm that these coatings have the desired effect on salt crystals, or transmit within wavelengths spectrum for IR-detectors and lasers. / ChpT 08-10

Semiconductor metal oxides can be induced by light with proper wavelength resulting in oxidation and reduction reactions for the transformation of water and oxygen molecules into active radicals. With this method, it is possible to obtain self-cleaning surfaces and products having antimicrobial properties. The aim of this study is to develop semiconductor metal oxide thin films for multifunctional glass products and the characterization of photocatalytic self cleaning and antimicrobial properties. As semiconductor metal oxides / titanium dioxide (TiO2), tin oxide (SnO2) and their binary mixtures (TiO2-SnO2) are selected because of their abundancy, non toxic properties, stability and the ability of absorbing light close to visible range. Also the effect of metal dopants such as praseodymium (Pr), palladium (Pd), silver (Ag) and iron (Fe) was examined with these metal oxides. The colloidal solutions were synthesized by using sol-gel method in order to apply the developed method to industrial usage as applying on large surfaces. The glass substrates were coated with the colloidal solutions by dip coating and the dried samples were calcined under air flow. The best calcination condition for pure TiO2 coated thin film was determined as 400oC for 45 minutes. Surface characterization studies were performed by using UV-Visible Spectrophotometer for band gap measurement, CAM for contact angle measurement, SEM for surface morphology and tophology. The methylene blue adsorption tests were carried out and the effective surface area of the samples were predicted by the Langmuir adsorption isotherm of samples. The photocatalytic activities of the coated thin films were measured with the degradation of organic materials as red wine and methylene blue, and with the antimicrobial activity tests as counting the number of viable E.coli cells. 61.2% deactivation of methylene blue stain was achieved over SnO2 coated thin films while this was 22.1% over TiO2 coated thin films after irradiation for 180 minutes. The superior photocatalytic activity was observed with TiO2 samples doped with Pd and Ag ions. The TiO2-SnO2 coated samples performed limited photocatalytic activity which is less than the activity of SnO2 coated samples which was confirmed with surface area measurements as SnO2 coated samples had higher surface area (9.81 cm2/cm2) than TiO2-SnO2 coated samples. Surface area increased with increasing the amount of SnO2 and it was in the following order: SnO2 &gt / 80% SnO2 + 20% TiO2 &gt / 50% SnO2 + 50%TiO2 &gt / 35% SnO2 + 65%TiO2 &gt / 20% SnO2 + 80% TiO2 &gt / TiO2.

Biologically inspired design is used as an approach for sustainable engineering. Taking a biologically inspired approach, one abstracts ideas and principles from nature, an inherently sustainable system, and uses them in engineering applications with the goal of producing environmentally superior designs. One such biological idea with potential environmental benefits for engineering is microscale and nanoscale surface roughness found on the Lotus plant and many other surfaces in nature. These surfaces repel water and aid in contaminant removal; this self-cleaning phenomenon is called the "Lotus Effect," in honor of the plant first observed to exhibit it. The structures responsible for the Lotus Effect inspired research and development of many technologies capable of creating hydrophobic, self-cleaning surfaces, and many potential self-cleaning surface applications exist beyond nature's intended application of cleaning. While statements have been made about the environmental benefits of using a self-cleaning surface, only limited scientific data exist. Artificial self-cleaning surfaces are successfully cleaned using fog or mist. This shows that such surfaces can be cleaned with less energy and water intensive methods than the more conventional methods used to clean regular surfaces, such as spray or solvent cleaning. This research investigates the potential environmental burden reductions associated with using these surfaces on products. A life cycle assessment is performed to determine the environmental burdens associated with manufacturing a self-cleaning surface, for three production methods: a chemical coating, a laser ablated steel template, and an anodized aluminum template. The environmental benefits and burdens are quantified and compared to those of more conventional cleaning methods. The results indicate that self-cleaning surfaces are not necessarily the environmentally superior choice.

This thesis focuses on the application of nanocrystalline transition metal oxide TiO2, WO3 and NiO thin films in new “green” building technologies. Specifically, their physicochemical properties in photocatalytic, self-cleaning and gas sensing applications are studied. There is an intimate connection between comfort issues, health, with connections to energy efficiency, leading to a need for intelligent building materials and green architecture. The importance of good indoor environment is augmented by the fact that modern man in developed countries spends some 90 % of his time inside buildings and vehicles. Poor air quality may lead to discomfort of the person inhabiting a building and in ultimately cause adverse health effects. Thin films of nanocrystalline TiO2 were prepared using reactive DC magnetron sputtering. Crystalline mesoporous films of WO3 and NiO were prepared using advanced gas deposition technique (AGD). The crystal structure, morphology, optical and chemical properties of the films were characterized by using grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), UV/Vis spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The photocatalytic properties and adsorption of both organic and inorganic molecules on pure and functionalized films were probed by in situ Fourier transform infrared spectroscopy (FTIR). The gas sensing properties of sensors based on TiO2, WO3 and NiO were investigated by conductivity measurements and noise spectroscopy. It was found for the first time that NiO based thin film sensors can be used to detect H2S and NO2 at low temperatures – down to room temperature. Hybrid WO3 sensors functionalized with multiwalled carbon nanotubes (MWCNTs) were used to detect NO2, CO and NH3 gases. These hybrid gas sensors show improved recovery properties compared to unmodified WO3 sensors. TiO2 based gas sensors were able to detect low concentrations of H2S by noise spectroscopy provided that the sensors were irradiated by UV light. Furthermore we show that sulphur is photo-fixated in crystalline TiO2 films upon simultaneous SO2 gas exposure and UV irradiation. Studies of the kinetics and identity of the photo-fixated sulphur complexes show that these are formed by photo-induced reactions between oxygen and SO2 at oxygen surface vacancy sites in TiO2. The sulphur modified TiO2 films show interesting self-cleaning properties compared to the pure films. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 739

Poor indoor air quality is a source of adverse health effects. TiO2 coatings deposited on well-illuminated surfaces, such as window panes, can be used to fully mineralize indoor air pollutants by photocatalysis. In such applications it is important to ensure stable photocatalytic activity for a wide range of operating conditions, such as relative humidity and temperature, and to avoid deactivation of the catalyst. In this thesis photocatalytic removal of the indoor-pollutant acetaldehyde (CH3CHO) on nanostructured TiO2 films is investigated, and in particular it is proposed how such films can be modified and operated for maximum performance. Catalyst deactivation can be reduced by purposefully changing the surface acidity of TiO2 by covalently attaching SO4 to the surface. Moreover, the overall photocatalytic activity on anatase TiO2 films can be improved by increasing the fraction of exposed reactive {001} surfaces, which otherwise are dominated by {101} surfaces. In the first part of the thesis mode-resolved in-situ FTIR is used to elucidate the reaction kinetics of CH3CHO adsorption and photo-oxidation on the TiO2 and SO4 – modified TiO2 surfaces. Surface concentrations of main products and corresponding reaction rates were determined. Formate is the major reaction product, whose further oxidation limits the complete oxidation to gaseous species, and is responsible for photocatalyst deactivation by site inhibition. The oxidation reaction is characterized by two reaction pathways, which are associated with two types of surface reaction sites. On the sulfate modified TiO2 catalyst fewer intermediates are accumulated, and this catalyst resists deactivation much better than pure TiO2. A hitherto unknown intermediate – surface-bound acetaldehyde dimer with an adsorption band at 1643 cm−1 was discovered, using interplay between FTIR spectroscopy and DFT calculations. The second part of the thesis treats the effect of increasing the relative abundance of exposed {001} facets on the photocatalytic activity of anatase TiO2 films prepared by DC magnetron sputtering. A positive effect was observed both for liquid-phase photo-oxidation of methylene blue, and for gas-phase photocatalytic removal of CH3CHO. In both cases it was found that the exposed {001} surfaces were an order of magnitude more reactive, compared to the {101} ones. Furthermore, it was found that the reactive films were more resilient towards deactivation, and exhibited almost unchanged activity under varying reaction conditions. Finally, a synergetic effect of SO4 – modification and high fraction of exposed {001} surfaces was found, yielding photocatalysts with sustained high activity. The results presented here for facet controlled and chemically modified TiO2 films are of interest for applications in the built environment for indoor air purification and as self-cleaning surfaces. / GRINDOOR

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-07-17T12:14:30Z No. of bitstreams: 1 RenataPriscillaDeAraujoSouza_TESE.pdf: 4547279 bytes, checksum: 4f04ca670330f1250ce98cf02b59ec9d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-07-17T15:04:44Z (GMT) No. of bitstreams: 1 RenataPriscillaDeAraujoSouza_TESE.pdf: 4547279 bytes, checksum: 4f04ca670330f1250ce98cf02b59ec9d (MD5) / Made available in DSpace on 2017-07-17T15:04:44Z (GMT). No. of bitstreams: 1 RenataPriscillaDeAraujoSouza_TESE.pdf: 4547279 bytes, checksum: 4f04ca670330f1250ce98cf02b59ec9d (MD5) Previous issue date: 2016-08-05 / Foram sintetizadas nanoestruturas de ZnO:Ag com nanopart?culas (NPs) de prata a 100 ?C atrav?s de energia micro-ondas com o objetivo de obter um material com propriedades fotocatal?ticas (self-cleaning) em baixos n?veis de energia e magn?ticas. As aplica??es pr?ticas do nanomagnetismo s?o diversas que v?o da geologia, da grava??o magn?tica, at? a medicina. Desse modo, o material foi obtido a partir dos precursores: acetato de zinco di-hidratado e nitrato de prata em diferentes concentra??es tais como ZnO1-x:Agx (x= 0, 0.01 e 0.02). Adicionando a s?ntese polivinilpirrolidona (como agente surfactante) e hexametilenotetramina como agente redutor/agente de precipita??o. Para sua caracteriza??o foram realizadas Difra??es de Raios-X (DRX), Microscopia Eletr?nica de Varredura e por Efeito de Campo (MEV/FEG), Microscopia Eletr?nica de Transmiss?o (TEM), an?lises de ?rea de espec?fica por isortermas Brunauer, Emmett e Taller (BET), Fotoluminesc?ncia (PL) e Espectrofotometria. Os resultados de DRX apontaram principalmente fases cristalinas de Wurtzita para o ZnO e c?bica de face centrada para nanopart?culas de prata met?lica. Atrav?s da espectrofotometria foi poss?vel confirmar por absorb?ncia no comprimento de onda do corante alaranjado de metila a fotocat?lise do ZnO dopado com 1 mol% de prata, sintetizado em 10 min no tempo m?dio de 2 horas e 30 min. Por transmit?ncia foi obtido o gap direto e indireto das composi??es estudadas. Todas as composi??es obtidas apresentaram a propriedade de fotoluminesc?ncia gerada por defeitos estruturais. A dopagem ocasionou para o material puro um deslocamento do verde para o amarelo e o vermelho em consequ?ncia da diminui??o do gap. Apresentou tamb?m pico referente ?s nanopart?culas met?licas de prata em torno de 390 nm. As propriedades magn?ticas foram investigadas atrav?s da an?lise das curvas de magnetiza??o em temperaturas espec?ficas e da magnetiza??o em fun??o da temperatura, obtidas utilizando-se um sistema PPMS. Com estes resultados, foi realizada a etapa de impregna??o das nanopart?culas em poliamida pelo m?todo de deposi??o por imers?o, para isso foi utilizado estireno e acrilato de butila. A caracteriza??o do nanorevestimento foi realizada atrav?s das an?lises de DRX, MEV/EDS, an?lise t?rmica (TG/DTA), Espectroscopia no Infravermelho com Transformada de Fourier (FTIR), Microscopia de For?a At?mica (AFM) e ?ngulo de contato. A avalia??o da propriedade self-cleaning foi baseada na altera??o da cor (?E) usando o espectrofot?metro por reflect?ncia. / ZnO:Ag/Ag nanostructures were synthesized at 100 ?C by microwave energy in order to obtain a material with photocatalytic properties on low energy levels and magnetics. The applications of nanomagnetism are diverse ranging from geology, magnetic recording, to medicine. Thus, the material was obtained from the precursors: zinc acetate dihydrate and silver nitrate (as dopant) in different concentrations such as ZnO1-x:Agx (x= 0, 0.01 e 0.02). Adding polyvinylpyrrolidone synthesis (as surfactant) and hexamethylene as a reducing agent/precipitating agent. For its characterization, the following techniques were performed to evaluate, Diffraction of X-Rays (XRD), Scanning Electron Microscopy and Field Effect (SEM/FEG), Transmission Electron Microscopy (TEM), analysis by isotherms Brunauer surface area Emmett and Taller (BET), Photoluminescence (PL) and Spectrophotometry. The XRD results indicated mainly crystalline phases of wurtzite ZnO for the and for face-centered cubic metallic silver nanoparticles. By undertaking spectrophotometric absorbance it was confirmed by the orange color wavelength methyl photocatalysis ZnO doped with 1 mol% silver synthesized in 10 minutes in an average time of 2 hours and 30 min. Transmittance was obtained with direct and indirect gap of the compositions. All powders obtained showed the photoluminescence property generated by structural defects. The doping of the pure material caused a shift from green to between yellow and red, thus confirming changes in the electrical properties of the same due to decrease in the gap and also showed peak regarding the metal nanoparticles silver around 390 nm. The magnetic properties of the samples were performed using the physical property measurement system (PPMS) from Quantum. Under these conditions the doping improved the photocatalytic property of ZnO. With these prior results, to prove this application the impregnation step was carried out with particles of polyamide by immersion deposition method (dip coating), for this a styrene and butyl acrylate was utilised. The characterization of nano coating ware used using the following techniques: XRD, SEM/EDS, thermal analysis (TG/DTA), Infrared Spectroscopy Fourier Transform (FTIR), atomic force microscopy (AFM) and contact angle. For evaluation of the self-cleaning for photocatalysis property was based on the color change (?E) using the spectrophotometer by reflectance before and after subjecting the samples to ultraviolet radiation for anthocyanins.

This thesis is focused on gathering all available information on the application forms of photocatalytic TiO2 in concretes, especially in the surface layers of precast and monolithic structures. The paper describes in detail the properties of titanium dioxide alone, his special abilities, leading to a substantial improvement of the environment, through photocatalysis. Further verification methods are described photocatalytic activity of titanium dioxide and titanium dioxide application in real projects. The practical part is tested recipes of secondary coatings from the production of company Precheza a.s. Přerov.

Biocatalytic membrane reactors combine the highly efficient biotransformation capability of enzymes with the selective filtration performance of membrane filters. Common strategies to immobilize enzymes on polymeric membranes are based on chemical coupling reactions. Still, they are associated with drawbacks such as long reaction times, high costs, and the use of potentially toxic or hazardous reagents. In this study, a reagent-free immobilization method based on electron beam irradiation was investigated, which allows much faster, cleaner, and cheaper fabrication of enzyme membrane reactors. Two industrial lipase enzymes were coupled onto a polyvinylidene fluoride (PVDF) flat sheet membrane to create self-cleaning surfaces. The response surface methodology (RSM) in the design-of-experiments approach was applied to investigate the effects of three numerical factors on enzyme activity, yielding a maximum activity of 823 118 U m2 (enzyme concentration: 8.4 g L1, impregnation time: 5 min, irradiation dose: 80 kGy). The lipolytic membranes were used in fouling tests with olive oil (1 g L1 in 2 mM sodium dodecyl sulfate), resulting in 100% regeneration of filtration performance after 3 h of self-cleaning in an aqueous buffer (pH 8, 37 C). Reusability with three consecutive cycles demonstrates regeneration of 95%. Comprehensive membrane characterization was performed by determining enzyme kinetic parameters, permeance monitoring, X-ray photoelectron spectroscopy, FTIR spectroscopy, scanning electron microscopy, and zeta potential, as well as water contact angle measurements.

Superhydrophobic coatings (SHC) with excellent self-cleaning and corrosion resistance property is developed on magnetite coated AISI SAE 1020 steel by using a simple immersion method. Roughness measurement, scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), contact angle measurement (CAM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), and qualitative characterization of self-cleaning behavior, antifouling property and durability of the coatings are assessed. A water contact angle as high as 152o on the coated surface with excellent self-cleaning and resistivity to corrosion and good longevity in atmospheric air is obtained. Self-cleaning test results prove that these surfaces can find applications in large scale production of engineering materials. Potentiodynamic polarization tests and EIS tests confirm that the superhydrophobic low carbon steel surfaces have better resistance to corrosion compared to bare steel and magnetite coated steel in 3.5% NaCl solution. But the longevity of the coated steel surfaces in 3.5% salt solution is limited, which is revealed by the immersion durability test. However, hydrophobic coatings (HC) have better stability in normal tap water, and it can stay unharmed up to 15 days. Finally, hydrophobic coatings on low carbon steel surface retains hydrophobic in open atmosphere for more than two months. Results of this investigation show surface roughness is a critical factor in manufacturing hydrophobic steel surfaces. Higher contact angles are obtained for rougher and more uniform surfaces. A linear mathematical relationship (y =6x+104; R2 = 0.93) is obtained between contact angle (y) and surface roughness (x).

During this project, photocatalytic material, nano sized titanium dioxide, was introduced into poly (lactic acid) to produce functional surface capable of self-cleaning property. Samples containing 0%, 5%, 10%, 15% and 20% titanium dioxide were prepared and etched with proteinase K to expose the nano particles on the surface. It was shown that the nano titanium dioxide could dispersed in the polymer matrix pretty well, it was also found that the nano particles affected the thermal and mechanical properties of the polymer matrix differently , due to difference in concentrations of nano filler. The self-cleaning property was evaluated by decolouration of stains caused by coffee and red wine, also by detecting degradation of methylene blue via a UV-vis spectrophotometer. By measuring changes in absorbance of light at 664nm wavelength after a maximum of 24h UV irradiation, it was possible to measure the degradation property of the samples. / Program: Masterutbildning i textilteknik