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Transport processes in hydrogels
Sárová, Michaela ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This master's thesis is focused on study of transport processes in hydrogels based on humic acids. For this purpose is used methods unsteady diffusion in cuvettes, which was studied the transport of organic dyes, specifically methylene blue and rhodamine 6G, in agarose hydrogel without the addition and with the addition of individual standards humic acids (Leonardite, Elliott Soil, Suwannee River II and Pahokee Peat). This method is based on spectrophotometric monitoring of concentration changes of dyes depending on space of the cuvette and on time. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. The experiments indicate that the presence of humic acid in the hydrogel greatly affects the transport of selected dyes.
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Methylene Blue Test for Plasticity Determination of Brick Clays
Jiroušek, Štěpán ; Stančík,, Hynek (referee) ; Sokolář, Radomír (advisor)
The Bachelor thesis is focused on methods for assesing the plasticity of ceramic raw materials (clays). The theoretical part describes the origin, species, chemical and mineralogical composition of these raw materials. Then we describe the preparations and standardized and nonstandardized methods of assesing the plasticity of clay used in the Czech Republic and abroad. The practical part describes executed tests of brick soils specimen used in the Czech Republic. The outcome of this work is to find correlations between these tests and the determined value of sorption of methylen blue.
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Study on structural and thermodynamic aspects of the interactions of humic substances with organic ions.
Fryšová, Eva ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
This bachelor thesis deals with the study of thermodynamic and structural aspects of the interactions of humic acids with organic ions. Methylene blue (dye) was used as a model organic ion. The interactions were studied by isothermal titration calorimetry and dialysis in diffusion cells. The calorimetric experiments showed exothermic nature of the interactions. Furthermore it was proved that increasing concentration of humic acids causes increasing of reaction enthalpy. The dialysis experiments found that increasing concentration of humic acids causes increasing of apparent equilibrium constant. The value of this constant was lower for modified humic acid due to the reduced content of the binding sites.
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Transport properties of humic gels
Sárová, Michaela ; Pospíšilová, Ľubica (referee) ; Klučáková, Martina (advisor)
This bachelor’s thesis is focused on study of transport properties of humic gels. For research of these properties was used diffusion method of organic dyes in diffusion cells which is based on spectrophotometric monitoring of concentration changes depending on time. Dyes used in the experiment were specifically methylene blue and rhodamine 6G and diffusion experiments were performed on an agarose hydrogel without the addition of humic acid, with the addition of unmethylated humic acid and then with the addition of methylated humic acid. The aim of this thesis was to investigate the effects of interactions between diffusing dye and the particular type of gel to the resultant effective diffusion coefficient of dye. It has been found that the presence of humic acid in agarose hydrogel greatly influences the transport of dyes.
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Transport Properties of Thin Films Based on Polyvinylalcohol
Blažková, Dominika ; Smilek, Jiří (referee) ; Kalina, Michal (advisor)
This bachelor thesis deals with the optimization of the preparation of hydrogel thin films based on polyvinyl alcohol (PVA). The first step was to optimize the preparation of films. PVA, with a molecular weight of 130 kDa, was used for the preparation of films and 10 wt.% solutions in ultrapure water were prepared from it. The heating duration time of the solution was set at 1.5 h at 90 °C. This was followed by drying at 50 °C for 24 h. Subsequently, PVA films were also prepared from solutions of methylene blue in water and from solutions of methylene blue in an aqueous NaCl solution. The prepared films were subsequently characterized by measuring their thickness, swelling ability, specific surface area and diffusion properties. The morphology of the PVA films was also visualized by SEM microscopy. All prepared films were smooth and had a very small specific surface area. The transport properties were monitored by the method of release into solution and Methylene blue was used as a probe. Release into 5, 10 and 20 ml of ultrapure water was observed. The results obtained show that the most methylene blue was released into the solution with the greatest volume and the release of methylene blue from the PVA film takes place freely without significant interaction with the matrix of the PVA film.
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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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Ionogenic fluorescence probes in research of colloidal system
Střondalová, Hana ; Burgert,, Ladislav (referee) ; Mravec, Filip (advisor)
This diploma thesis studied the interaction of ionic and amphiphilic fluorescent probes with polyelectrolytes. The research of such colloidal system could be helpful in deeper understanding of interactions between polyelectrolytes and surfactants. The aim of this thesis was to determine whether ionic or amphiphilic probes are suitable for this research. Two polyelectrolytes, sodium polystyrene sulfonate and hyaluronan were used in this study. Interactions of polyelectrolytes with fluorescent probes (4-Di-2-Asp, methylene blue, dodecyl acridine orange, DiO and DiA) were studied in this work. Then cationic surfactant cetyltrimethylamonium bromide was added to this system. Samples were studied using fluorescence and UV/VIS spectroscopy. Emission and absorption spectra of these probes were recorded. This experiment was based on hypothesis that due to positive charge these probes will bind to the negatively charged polyelectrolyte. Formation of dimers or other aggegates was presumed for fluorescent probes dodecyl acridine orange and methylene blue. When 4-Di-2-Asp was used,changes in fluorescence intensity and absorption spectra in connection with possible formation of aggregates was supposed to be observed. It should be noted that formation of dimers for 4-Di-2-Asp is not described in literature. The formation of dimers wasn't clearly demonstrated during the measurement. Formation of dimers was observed only with dodecyl acridine orange. Probes DiO and DiA were used only in the study of the interaction with polyelectrolytes. These fluorescent probes showed up as inappropriate, because they adsorbed on tube walls. When cationic surfactant was added to hyaluronan-fluorescent probe system, surfactant pushed away fluorescent probe and bonded electrostatically to negatively charged groups of polyelectrolyte.
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Hydrogels with carbon fibers
Kučerová, Barbora ; Bouška,, Marek (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of the behaviour of carbon fibers in the hydrogel, especially the viscoelastic modules od these gels ort he coefficient of color transmission through the gel. The main goals were to optimize the samples and measure their viscoelastic modules on a rheometer, in several different modes. This was followed by simulation of physiological conditions for selected samples and their measurement on the rheometer. There was also an experiment of continuous diffusion in cuvettes, in which the penetration of the dye through the gel with the addition of fibers and for comparison also without them. Last but not least diffusion pairs were prepared.
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Transport properties of agarose hydrogels
Vlasák, Jan ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
This thesis deals with the transportation processes of electrolytes using simple organic dyes as diffuse probes. The main goal of the work concerns a study of a diffusion mobility of the selected probes being in a form of simple organic dyes in a hydro-gel matrix based on a thermo-reversible linear polysaccharide, i.e., agaroses, functioning as semi-permeable membranes. The thesis describe diffusion processes used for determination of the basic diffusion parameters such as an efficient diffusion coefficient, reputed diffusion coefficient, separating coefficient, concentration of the dye in a gel and the time needed for the diffusion going throughout the entire layer of the gel. Attention is paid also to the environment in which the diffusion processes are implemented (in particular in view of the gel-like samples), porousness of the structure and its mechanical properties.
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