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Monitoring of photocatalytic activity using redox dyes
Uhrová, Ivana ; Drbohlavová, Jana (referee) ; Veselý, Michal (advisor)
The bachelor thesis deals with assessment of photocatalytic activity of titanium dioxide. The easiest and simultaneously the quickest way is bleaching of indicator ink based on redox dye. The theoretical part contains characteristics of several similar dyes and a description of ink-structure effect on total bleaching speed. The experimental part elaborately describes bleaching of indicator ink based on redox dye 2,6 dichloroindophenol, depending on the number of ink layers on photocatalytic active surface as well as on total amount of glycerol.
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Material printing on R2R printer
Knobová, Klára ; Vališ, Jan (referee) ; Veselý, Michal (advisor)
This diploma thesis deals with material printing using roll to roll material printer. Several kinds of printing inks were prepared and their parameters, like viscosity and homogeneity were optimized. Corona treated PET foil was used as the flexible substrate. Thin layers of function material were prepared by coating by using the smooth cylinder and slot die method. Layers homogeneity was characterized by optical density. Layer thickness was measured by profilometer.
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Photocatalytic Activity of Titanium Dioxide Printed Layers
Novotná, Michaela ; Jančovičová, Viera (referee) ; Veselý, Michal (advisor)
This diploma thesis was focused on the preparation of self-cleaning and photocatalyticaly active titanium dioxide thin films. Transparent and porous thin layers of titanium dioxide were prepared from sol-gel containing titanium tetraisopropoxide (TTIP) as precursor with addition polyethylene glycol (PEG). Transparent thin layers of titanium dioxide were also prepared from colloidal solution titanium dioxide. The immobilization of thin titanium dioxide layers was performed by a sol-gel process on the soda lime glasses. Diffusion of sodium cation from soda lime glasses into titanium dioxide layer were blocked. Sol was deposited by printig method – micropiezo deposition. Sol and thin titanium dioxide layers were characterised by the physical-chemical method. For prepared sol viscosity, density and surface tension were measured. Thickness and hydrophilicity of titanium dioxide layers also were studied. The photocatalytic activity of the printed titanium layers were tested via the photocatalytic degradation of the 2,6-dichlorindophenol. The influence of addition PEG into the sol and influence of sol loading was studied. It was found that the addition of PEG into the sol significantly increased the photocatalytic activity of titanium dioxide layers.
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Kinetics of Inkjet Dyes Degradation
Buteková, Silvia ; Mikula, Milan (referee) ; Klusoň, Petr (referee) ; Veselý, Michal (advisor)
The stability of inkjet print is influenced by a lot of factors. Mutual effects of these factors accelerate the print degradation. The surrounding environment in image stability plays an important role, when the prints degrade especially by the light. The degradation of inkjet prints is presented as a decrease of dye or multiple dyes. It is necessary to know the dye concentration for the dye decrease prediction in the time. This dissertation thesis deals with the study of kinetics and changes in electron and molecular structure of digital photography prints after accelerated ageing tests. The study of resistance of inkjet prints was realized on one type of media using three different sets of inks. Changes in printed colours were measured and evaluated in calibration (by PLS calibration and least squares method). On the basis of calibration the dye decrease prediction of real samples in receiving layer was evaluated. Changes in electron and molecular structure were analysed on KBr pellets by FTIR an UV-Vis spectroscopy.
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Self-cleaning Properties of Thin Printed Layers of Titanium Dioxide
Králová, Marcela ; Brezová, Vlasta (referee) ; Krýsa, Josef (referee) ; Veselý, Michal (advisor)
Tenké vrstvy oxidu titaničitého byly imobilizovány na sodnovápenatá skla a skelný uhlík použitím jak techniky materiálového tisku tak metodou chemického napařování. Pro přípravu titaničitých solů byly použity metody sol-gelu a nebo hydrotermální syntézy. Struktura připravených vrstev byla zkoumána rastrovací elektronovou mikroskopií a mikroskopií atomárních sil. Krystalická struktura připravených TiO2 byla analyzovány pomocí XRD metody. Fotoindukováná superhidrofility pripravených vzorků byla charakterizována měřením kontaktních úhlů. Fotokatalytická aktivity připravených vzorků byla testována na fotokatalytické oxidaci 2,6-dichlorindofenolu a kyseliny mravenčí. V případě sol-gel vrstev byl zkoumán vliv množství naneseného TiO2 a množství PEG, který byl do solu přidán jako praskliny potlačující činidlo. V případě hydrotermálních vrstev byl zkoumán vliv času a teploty syntézy a množství vrstev na výslednou účinnost vzorku. U chemicky napařených vzorků byl zjišťován vliv intenzity záření. Byla porovnána fotokatalitická aktivita vrstev připravených materiálovým tiskem a chemickým napařováním a byl vyhodnocen nejaktivnější vzorek.
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Lightfastness of inkjet prints
Buteková, Silvia ; Čeppan, Michal (referee) ; Veselý, Michal (advisor)
The stability of inkjet print is influenced by a lot of factors. Just the surrounding environment in image stability plays an important role. When the prints fade, not only this does occur by light exposure, but also considerable effect has relative humidity, ozone and other air pollutants. The types of receiving layers or ink composition belong to other factors, which affect the stability of prints. This diploma thesis deals with the long-term ageing of digital prints produced by ink jet technology. The study of resistance of inkjet prints was realized on nine different types of media. Samples were prepared with use of dye-based and pigment-based inks. The attention was especially focused on the influence of light on print durability, but study was also oriented on the impact of ozone. The samples were exposed to the indoor daylight. Changes in printed colours were measured and evaluated in colorimetric quantities. In this study of inkjet prints degradation the dependence of colour gamut volumes on UV and VIS exposure dose was evaluated.
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Printed chemical sensors of UV light
Fanglová, Michaela ; Čeppan, Michal (referee) ; Veselý, Michal (advisor)
The main task of the bacherol´s thesis was to prepare a photosensitive layer reacting to the radiation dose with a color change. And to calibrate the prepared dosimeters to the required values of the radiation doses of the UVB radiation. This bacherol´s thesis is about light dosimeters, which are based on photochemical reactions. These reactions take place in a thin polymer layer. The experimental study focoused on the preparation and application of photosensitive compositions. These prepared dosimeter compositions were exposed to different doses of UVB radiation, where the color response to the exposure was monitored.
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Self-cleaning ability of organic photo-active layers
Těthal, Vít ; Vala, Martin (referee) ; Veselý, Michal (advisor)
In this paper, methodes of determination of singlet oxygen (decolorization methodes, luminiscence detection, reaction with anorganic compounds, electon paramagnetic resonation, detecting of singlet oxygen luminiscence, detecting of absorption in IR region) and determination of efectivity of photoactive layers (photobleaching of dye aqueous solution, photodegradation of a solid fatty deposit, photoreduction of an organic dye, photooxidation of sodium salt of terephtalic acid, degradation of 1,3-diphenylisobenzofuran (DPIBF), degradation of diketopyrrolopyrrole (DPP), degradation of acridine orange) are summarized, including principle and procedure. In experimental part, 2 of these methodes (DPIBF and DPP degradation) were chosen and tested. Reaction rate constant and conversion were measured. It was found out that DPIBF methode is quick, reliable and reproducable.
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Barrier Polymeric Layers for Inkjet Prints Protection
Štěpánková, Eva ; Čeppan, Michal (referee) ; Ďurovič, Michal (referee) ; Veselý, Michal (advisor)
Práce podává přehled o dostupných a využívaných metodách, normách pro testování a hodnocení světlostálosti barevných fotografií a tisků. Bylo provedeno porovnání jednotlivých platných norem a návrhů na hodnocení. Tato práce pojednává o ochraně inkjetových tisků pomocí lakování. Byl připraven lak kompatibilní s fotografickými médii. Připravená kompozice byla obohacena o UV absorbéry EVERSORB ve dvou koncentracích. Pro srovnání byly také testovány tři druhy komerčních ochranných fotografických laků. Výtisky se třemi barvivovými inkousty opatřené lakovou vrstvou, byly vystaveny jak urychlenému světelnému stárnutí v xenonové testovací komoře, tak urychlenému stárnutí v ozonové testovací komoře. Na základě měřených odrazových spekter byl vypočítaný objem barvového gamutu pomocí softwaru Volga. Byl sledován úbytek gamutů v průběhu světelného stárnutí i při expozici ozonem. Stárnutí vzorků probíhalo do ukončení testu, nebo do dosažení kritéria 30% úbytku objemu barvového gamutu. Také bylo pozorováno selhání recipročního zákona, které ukazuje na jistou nepřesnost při předpovědi dlouhé životnosti vzorků. Pomocí změny barvového gamutu byla posuzována ochrana připraveného laku před UV záření a ozonem. Studované vrstvy laků byly dále charakterizovány na prostupnost kyslíku a vodní páry.
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Degradation of Inkjet Printouts
Stančík, Jiří ; Kaplanová, Marie (referee) ; Čeppan, Michal (referee) ; Veselý, Michal (advisor)
Inkjet printing technology became a popular technology for printing digital photographs in the last decade. There is a big variety of both original and alternative (cheaper) inks and print media for the consumers. But there is a question if the cheaper material provides also comparable printout quality. For this reason, it is important to test the properties of such inkjet printouts. There are several ways how to test the lightfastness of the printouts: long term storage under environmental conditions, or short, accelerated ageing tests. The stability of printouts is affected by many factors, such as ink-receiving layer, ink composition, UV and visible light intensity and air pollutants concentration in the environment. Some inkjet printouts exposed to light usually undergo surprisingly fast fading, but light is not the only dangerous condition for inkjet printout. The two types of test targets printed with dyebased inkjet inks on various paper types were subjected to both accelerated test in a xenon test chamber and light and environmental pollutants long-term test in a sunny indoor corridor. The values of light intensity were continuously monitored and samples properties were regularly measured with a spectrophotometer. Another type of testing included accelerated ozone ageing of inkjet dyes. The colour gamuts and gamut volumes were calculated from collected spectral data. Total colour difference E*ab was also evaluated, its increase served as a tool for finding the formal printout degradation rate constant. It was found out that the dyes in ink-receiving layers of printouts underwent significant degradation in all tested conditions. The degradation rate depended on the type of used print media. The reciprocity behaviour of printouts was also studied. Recent inkjet printouts testing miss some actual ISO norm which should show the way of effective lightfastness evaluation. One of the main aims of this work was to find some new and alternative ways of inkjet printouts lightfastness evaluation. The method of printed inks concentration determination from the test charts spectrophotometric measurements was also proposed.
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