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Self-assembled layers based on silicon
Bábík, Adam ; Veselý, Michal (referee) ; Čech, Vladimír (advisor)
Thin film deposition, characterization and properties of self-assembled monolayers based on silicon were studied with emphasis on the SA monolayers deposited from vinyltriethoxysilane and vinyltrichlorsilane. The thesis is aimed at basic properties of the SA monolayer and explanation of its growth. Methods and techniques used for analysis of the monolayer were described as well. Contact angle measurements and an evaluation of the surface free energy are depicted in details. The deposited SA layers were observed with respect to their chemical composition and surface morphology by X-ray photoelectron spectroscopy (XPS), ellipsometry and atomic force microscopy (AFM).
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Preparation and testing of large titanium dioxide layers
Maršálek, Blahoslav ; Kočí,, Kamila (referee) ; Veselý, Michal (advisor)
The aim of this bachelor theses was testing of mechanical and photocatalytical properties on printing suspension with different composition of the titanium dioxide with organosilicate binder printed on the PET foil. The cross-cut test was used to evaluate mechanical properties of the printed film surface. The photocatalytic activity was tested by decomposition of the acid orange 7 as a model pollutant using the UV-VIS spectrophotometry. Based on the results from experiments, the formal rate constants and the parameters of the mechanical stability of surfaces were obtained. The results shoved, that there is a clear correlation between the rate of organosilicate and titanium dioxide – the more is titanium dioxide, the higher is photocatalytic activity, but lower mechanical stability of the printed surface, what is probably caused by covering of titanium reaction centers by organosilicate. Possibilities of enhancing photocatalytic efficiency of the titanium dioxide and organosilicate composition are also discussed in this thesis.
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Photocatalytic sensor of oxygen
Filipi, Denisa ; Kubáč,, Lubomír (referee) ; Veselý, Michal (advisor)
This bachelor thesis deals with the optimization of inks for the preparation of photocatalytic oxygen indicator.The aim was to prepare a photocatalytic oxygen indicator with sufficient colour change after photoreduction and after reverse photooxidation.The indicator is based on semiconductor particles (TiO2), a sacrificial electron donor, a redox dye and a polymer which serves as a binder. The effect of the polymer used on the appearance of the prepared layers deposited on the PET film was investigated. The effect of the concentration of sacrificial electron donor on the rate of photoreduction (transition to the colourless leuco form) and reverse photooxidation of the indicator (transition of the leuco form to the coloured form) was also studied. Based on the study of the indicators, the rate constants for photoreduction and photooxidation of the prepared indicators were determined.
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Study of thin film organic materials thickness
Hegerová, Lucie ; Veselý, Michal (referee) ; Zmeškal, Oldřich (advisor)
The diploma thesis deals with the determination of thickness and refractive index of thin organic films using image analysis. In the theoretical part there are described principles of the methods, which are used to prepare the films (spin coating, inkjet printing, vapour deposition), the characteristics of thin films, ways of finding out the thickness and refractive index of substances (weight methods, electric methods, method based on measurement of absorption coefficient of light, interference microscopy, ellipsometry) and also image analysis (harmonic and wavelet analysis). Interference microscope Epival - Interpako (Carl Zeiss Jena), digital camera Nikon Coolpix 5400 and computer were used for the determination of thickness and refractive index. The thicknesses of layers were set on the basis of interference images of edges and grooves – both from the side of the metal contact and the side of underlying glass. The refractive indices of thin layers were then set using the recorded figures. In the final part of the thesis there are discussed the results of interference images photographed along the full length of the aluminium contact which are used for measuring electrical characteristics of DPP structures. The produces are thicknesses and refractive indices of individual layers.
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Photocatalytic activity of hybrid titanium dioxide layers treated by plasma
Koukolová, Anna ; Králová, Marcela (referee) ; Veselý, Michal (advisor)
The bachelor thesis deals with photocatalytic activity of thin layer of titanium dioxide deposited onto PET flexible foil treated by plasma. Photocatalytic activity is measured by two different methods, degradation of dye Acid Orange 7 and benzoic acid. Possible model compounds for evaluation of photocatalytic activity as well as deposition techniques for preparing thin layers of photocatalyst were discuss in the theoretical part. Changes of photocatalytic activity were found insignificant with plasma treatment. Evaluation used Acid Orange 7 is suitable. Unlike method with benzoic acid was discovered inappropriate for measuring of photocatalytic activity for photocatalyst deposited onto PET foil.
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Study of refractive index dispersion dependences with using of interference microscopy
Schmiedová, Veronika ; Veselý, Michal (referee) ; Zmeškal, Oldřich (advisor)
The master´s thesis deals with the study of optical properties of thin transparent layers on the organic materials (PPV, P3HT, TiO2, DPP) and especially with the determination of dispersion dependences of refractive index of prepared thin layers. In the theoretical part there are described principles of deposition thin layers of the analyzed materials and their properties. In addition, there are also described methods of optical properties measurements (optical and interference microscopy and ellipsometry). The combination of interference microscope with digital camera was used for determination of refractive index. The image analysis was used for the determination of parameters (with help of the software HarFA). The images of thin layers surfaces were analyzed from the side of the metal contact as well as from the side of glass. In conclusion, there are presented results of the refractive index of the thin layers obtained from the measured values.
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Printing of up-conversion marks
Azariová, Viktória ; Ďurovič, Michal (referee) ; Veselý, Michal (advisor)
The subject of this these is a preparation and printing of upconversion marks that have been printed by two printing techniques, namely screen printing and pad printing. The makrs were designed to visualize another chemical code identifiable by instrumentation. The impact of chemical code components on the fluorescence intensity of upconversion marks and the impact of individual components on printability and print sustainability were studied. The upconversion pigment was excited by NIR laser.
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Ink formulation for chemical labels printing
Martiniaková, Ivana ; Krystyník,, Pavel (referee) ; Veselý, Michal (advisor)
This diploma theses is about the study of the effect of individual components of printing compositions intended for material printing of identificaton codes, read by X-ray fluorescence. Two printing technologies were used – screen printing and pad printing. The composition of the print compositions has been optimized in term of visual recognition, print repeatability, a dry matter content providing an X-ray fluorescence signal, as well as optimization of the material print process leading to the creation of invisible identification tags for archive documents.
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Photocatalytic activity of hydrothermal titanium dioxide
Lepičová, Martina ; Jančovičová, Viera (referee) ; Veselý, Michal (advisor)
Hydrothermal synthesis is one of the most widely used methods for preparing nanoparticles of titanium dioxide. The process carried out at elevated temperatures and pressure, which facilitates the transformation of amorphous to crystalline titanium dioxide. Change of reaction conditions of the process (reactants concentration, temperature, time, pH, etc.) leads to change in morphology, microstructure and crystallinity of titanium dioxide nanoparticles. In this work the method of titanium dioxide preparation is briefly described. The titanium dioxide was prepared from a precursor titanium oxochloride and potassium hydroxide as the precipitating agent. Thus prepared titanium dioxide was immobilized on a glass substrate by material printing. This is a modern, highly precise and contactless method for preparing thin films. The photocatalytic activity of printed thin films of titanium dioxide was investigated by degradation of 2,6-dichlorindophenol at different irradiance. It was found that the sample prepared by hydrothermal treatment at 160 °C shows very similar photocatalytic activity to Degussa P25.
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Deposition and characterization of SA layers from vinyltriethoxysilane
Veverka, Miroslav ; Veselý, Michal (referee) ; Čech, Vladimír (advisor)
Development of composite material is very much progressive sector and leads to evolution of material with new property. This type of material has one, but important deficiency. It is small adhesion armature to matrix. My study is sight on improvement adhesion the surface by deposition self assembled (SA) monolayer from organosilanes. Property of this layer, like thickness, surface tension, homogenity and wettability, was evaluated by the contact angle measurement and spektroscopical elipsometri.
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