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Sensor of food packaging environment quality
Dobiáš, Vojtěch ; Syrový, Tomáš (referee) ; Veselá, Mária (advisor)
The aim of this study was to prepare thin polymer layers able to give a color change response to oxygen. Thin layers were prepared with different polymers and dyes. The rate of photocatalytic reduction of a dye and the rate of the color change response to oxygen were studied. To verify oxygen sensitivity of a prepared layer, oxygen absorbers were used to create anaerobic conditions. The effect of visible light irradiation on a prepared layer was examined as well. Influence of glycerol content on the kinetics of the photocatalytic reduction and the color change response was studied. Considering both reactions, the glycerol content of 1 % was found to be the most suitable. Methylene blue in prepared layer was reduced 48 s after previous UVA irradiation with intensity of 0,1 mWcm-2. The color change response to oxygen is readily distinguished by the naked eye within 20 minutes.
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Transition metal oxides for chemical sensors
Volfová, Lenka ; Tyrpekl, Václav (advisor) ; Zelinger, Zdeněk (referee) ; Myslík, Vladimír (referee)
Outdoor air pollution is one of the main environmental problems today. Its monitoring is, among other things, given by the European Union directive (2008/50/EC) on air quality and places high demands on the quantity and reliability of sensors deployed in our immediate surroundings. In order to continuously monitor large number of habitats, it is necessary to develop simple and inexpensive types of sensors. Figure 1 shows an example of such a sensor. The topic of the dissertation is the preparation by physical methods and the study of the surfaces of thin oxide layers as an active medium for the above-mentioned applications. The thesis investigates the possibility of materials preparation by pulsed laser deposition, discharge in a hollow cathode and magnetron sputtering thin film materials for chemiresistor sensors based on copper and tungsten oxides, luminescent Eu doped ZnO layers and resonant so-called QCM, where a quartz resonator was covered with a layer of black aluminium showing a large specific surface in order to increase the sensitivity of these types of sensors. Since the state and properties of the surface are crucial for the function of these types of sensors, an integral and important part of the work is the characterization of the structural properties of the prepared layers,...
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Material printing upscaling of chemical sensors to R2R techniques
Fanglová, Michaela ; Krystyník, Pavel (referee) ; Veselý, Michal (advisor)
The main task of the diploma´s thesis was to prepare mixtures for printing ozone and UVB sensors. Subsequently, to optimize the compositions and rheological properties of these mixtures for the preparation of chemical sensors for printing by production R2R machnies, including their calibration to detect required doses of ozone and UVB radiation. The experimental study focoused on the laboratory preparation of mixtures for chemical sensors and their subsequent conversion and printing on semi-operational and production R2R machines. The transfer of production to a larger scale was achieved through changes in the rheological properties of the compositions. The prepared ozone sensors were exposed to different ozone doses and their color change was monitored as a function of the ozone dose. The UVB sensors were calibrated to the required UVB dose and their colour response to the UVB dose was monitored.
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Sensor of food packaging environment quality
Dobiáš, Vojtěch ; Syrový, Tomáš (referee) ; Veselá, Mária (advisor)
The aim of this study was to prepare thin polymer layers able to give a color change response to oxygen. Thin layers were prepared with different polymers and dyes. The rate of photocatalytic reduction of a dye and the rate of the color change response to oxygen were studied. To verify oxygen sensitivity of a prepared layer, oxygen absorbers were used to create anaerobic conditions. The effect of visible light irradiation on a prepared layer was examined as well. Influence of glycerol content on the kinetics of the photocatalytic reduction and the color change response was studied. Considering both reactions, the glycerol content of 1 % was found to be the most suitable. Methylene blue in prepared layer was reduced 48 s after previous UVA irradiation with intensity of 0,1 mWcm-2. The color change response to oxygen is readily distinguished by the naked eye within 20 minutes.
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