National Repository of Grey Literature 71 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Photocatalytic Composite Coatings of Graphitic Carbon Nitride and Siloxane Binder
Kubát, Michael ; Stavárek,, Petr (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with the deposition and subsequent processing of a liquid formulation of graphitic carbonitride with a siloxane binder, which could be used as a photoanode or as a photocatalyst for self-cleaning processes. The prepared layers were deposited by the doctor blade method. The heights of the deposited layers were expressed by profilometry. The photocatalytic activity was studied by rhodamine B degradation.
Natural dyes for smart packaging
Nyklesová, Ludmila ; Dzik, Petr (referee) ; Veselá, Mária (advisor)
This thesis focuses on the use of natural dyes in smart food packaging as pH change indicators. The theoretical part of the thesis describes smart packaging, which can be divided into active and intelligent packaging. Within intelligent packaging, the thesis focuses mainly on pH indicators, including their composition, i.e., the polymer used and the dyes, with an emphasis on anthocyanin dyes. The theoretical part also includes a description of the methods used to measure the color changes of prepared indicators. In the experimental part of the thesis, anthocyanin dye is extracted from Aronia melanocarpa berries and thin films containing the anthocyanin extract are prepared. The color change of the prepared thin layers is further studied in an environment with a low concentration of ammonia. Layers that showed a reaction to the ammonia environment were subsequently overprinted with white UV varnish, and their reaction to an environment with low ammonia content was observed.
Hydrogel carriers of microbial cultures for contact sampling of biocidic surfaces
Antálek, Adam ; Králová, Marcela (referee) ; Dzik, Petr (advisor)
This bachelor thesis is focused on the development and optimization of material for biological sampling of active surfaces with biocidal properties. The aim was to modify polyvinyl alcohol with methacrylic groups, to determine the degree of conversion of the prepared polymer, to optimize the preparation of hydrogels. Furthermore, the aim was to investigate the effect of copolymerization aditives of sodium methacrylate and polyethylene glycol dimethacrylate on the swelling and mechanical properties of hydrogels. It was found that 20% vol. the content of polyethylene glycol dimethacrylate most significantly increases the swelling rate in the initial phase of water absorption. The hydrogels of this composition and the hydrogels consisting only of pure methacrylated polyvinyl alcohol, despite the assumption, increase the mechanical resistance after swelling to equilibrium. The hydrogels of the composition containing both copolymer aditives absorb water at equilibrium to the highest extent of the investigated compositions.
Fabrication and properties of photocatalyst layers with controlled porosity
Blecha, Tomáš ; Gemeiner, Pavol (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with fabrication of photocatalyst layers with controlled porosity and investigation of their properties. Polyvinyl pyrrolidone, polyethylene glycol and polyvinyl alcohol were used as templating agents. Prepared compositions were deposited on FTO glass using a drop-casting method and annealed at 450 °C. The structure of thin films was examined using optical and electron microscopy. The thin films were subsequently studied by photoelectrochemical measurements. Most resulting compositions showed relatively good electrical and optical properties, hinting at a potential for future use in practice.
Dielectric layers fabricated by material printing
Olejníková, Marie ; Pekárková, Jana (referee) ; Dzik, Petr (advisor)
This master‘s thesis deals with the use of the material printing method for fabrication of dielectric films. Final high- dielectric composite film consisted of BaTiO3 based inkjet-printed layer and spin-coated polyvinylpyrrolidone (PVP) layer. The effect of ball-milling on BaTiO3 suspension was studied by DLS a XRD methods. Printing formulation and parameters of inkjet printing were optimized with respect to the surface morphology of printed BaTiO3 films using contact profilometry method. Impedance analysis was used to determine the value of effective dielectric constant of the final dielectric composite film using thin film capacitor structure. Effective dielectric constant of composite dielectric film was 4,9 ± 0,4.
Characterization of plasma activated water for biomedical applications
Šindelková, Kateřina ; Dzik, Petr (referee) ; Kozáková, Zdenka (advisor)
The aim of this master thesis is to characterize plasma activated water (PAW) prepared in various plasma systems using direct and indirect interaction of plasma with liquid or its surface. Plasma was generated by electric discharges at atmospheric pressure. The prepared plasma-activated water was studied with respect to its use in biomedical applications. The theoretical part deals with plasma activated water. It contains a description of the PAW preparation, its characterization in terms of produced particles or its physico-chemical properties. Also, methods for antimicrobial activity estimation or colorimetric determination of produced particles are described in this section. In the experimental part of this work, the types of discharges that were used for the PAW preparation and their comparison are presented. Two types of liquids were selected for the activation, namely distilled and tap water. Subsequently, concentrations of selected reactive particles in PAW (hydrogen peroxide, nitrates and nitrites) produced in three different plasma systems were determined. Besides the comparison of reactive particles production in various systems, their time stability was studied as well. Over time after the PAW preparation, the values of active particles concentrations have changed due to mutual interactions between the particles. Mainly, nitrites were oxidized to nitrates or vice versa depending on the PAW type and other conditions. Part of the work was also monitoring selected physical properties of PAW, namely pH value and specific conductivity. It has been found that PAW does not retain its activated properties for too long, depending on the type of preparation and methods of storage. Therefore, one of the important goals of this work was to determine and compare suitable storage conditions for PAW with respect to its potential biomedical applications.
Tungsten trioxide coatings fabricated from nanocrystalline suspension and binder
Filipská, Markéta ; Zlámal,, Martin (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with layers of tungsten oxide, which are prepared from a nanoparticle suspension and a binder. The coating composition consisted in the first case of ground tungsten oxide nanoparticles alone, then of acetylated peroxotungstic acid alone and finally of a mixture of ground tungsten oxide mixed with acetylated peroxotungstic acid. The compositions thus formed were applied to conductive FTO glass and thus act as photoanodes. A stainless steel needle is used as a counter electrode for volt-ampere measurements. The work focuses on the study of physicochemical properties of prepared photoanodes and their optimalization in order to obtain the highest possible values of generated photocurrents. The electrical properties of all cells were determined using voltammetric characteristics.
Fabrication of conducting patterns by material electroless plating of printed precursor
Kováčová, Silvia ; Gemeiner,, Pavol (referee) ; Dzik, Petr (advisor)
The subject of this diploma thesis is the preparation of conductive structures by electroless plating of an extruded precursor. The experimental part deals with the preparation of standard patterns based on the length of immersion time in a coppering bath. The precursor layers were applied with Fujifilm Dimatix to various receiver substrates. The individual substrates with the precursor layer were immersed in the copper solution within different time intervals. The structure of the layers of grown copper and their thickness was characterized by a profilometer.
Fabrication of transparent oxidic conducting coatings by material printing
Žáková, Michaela ; Krystiník,, Pavel (referee) ; Dzik, Petr (advisor)
Thin transparent conductive layers containing ATO nanoparticles are a modern material that has found use in a wide range of optoelectronic applications. For liquid phase deposition there were designed and prepared compositions using a „brick and mortar“ approach combined templating agents. A sol-gel solution formed of inorganic precursors of tin chloride and antimony trichloride in the presence of ATO nanoparticles was mixed with a surfactant to improve the structure and wettability of applied films. Polyethylene glycol, polyoxyethylene (20)cetylether, sodium dioctylsulfosuccinate and polyvinylpyrrolidone were used as templating agents. Thin layers of these compositions were applied by the spin-coating method. Characterized parameters were resistivity, thickness and turbidity. A resul compositions showed relatively good electrical properties and high transparency and a potencial to be used for material printing.
Plasmochemical treatment of substrates and coatings in R2R arrangement
Patakyová, Sylvia ; Homola,, Tomáš (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with the comparison of the properties of two titanium dioxide types, which is due to its semiconductive properties commercially used in photoactive layers. The main reason for comparing these sources is their different price which can have possible impact on industrial use. Photoactive layers formed by various wet deposition techniques are cured by atmospheric plasma. The effect of plasma on individual depositions is investigated by electroanalytical methods. Voltametric and chronoamperometric characteristics indicate the dependence of the substrate activity on the time or distance of plasma treatment. Surface of composites were scanned by SEM and the mutual surface properties of untreated composites and the effect of siloxane binder on them were analyzed.

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