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Plasmachemical deposition and characterization of hexamethyldiloxane thin layers
Blahová, Lucie ; doc. Mgr. Vít Kudrle. Ph.D. (referee) ; Krčma, František (advisor)
Thin films have been used to modify surface properties of various materials for many years. Plasma Enhanced Chemical Vapor Deposition (PECVD) is one of the possible methods for their preparation and this technique is applied in this work as well. An organosilicone – hexamethyldisiloxane – is used as precursor. Thin films are created on the surface of the substrate using mixture of precursor and oxygen in radiofrequently excited capacitively coupled plasma. The aim of the thesis is to find the optimal deposition conditions for production of transparent thin layers with good barrier capabilities, low oxygen transmission rate especially. Thin film depositions were realized for different compositions of the deposition mixture in continuous and pulsed mode of plasma with varying supplied power and duty cycle values. The deposition process itself was monitored in situ by optical emission spectroscopy. Thin film coatings were analyzed to determine their physical chemical properties (infrared spectroscopy, surface energy) and barrier properties. Using optical emission spectroscopy, important particles were identified in the deposition plasma. Vibrational, rotational and electron temperatures were determined from relative intensities of chosen fragments. Composition of thin films was studied by infrared spectroscopy. The best results of oxygen transmission rate were achieved with layers prepared from deposition mixture with high oxygen content. It was possible to improve barrier properties by performing deposition in pulsed plasma mode with 20–30% duty cycle. In this diploma thesis, optimal deposition conditions of thin films from hexamethyldisiloxane with low oxygen transmission rate were determined. It is possible to use these results in practical applications, such as corrosion inhibitors for archaeological objects. Optionally, they can be used in various industry branches where it is desirable and feasible to prevent oxygen access to the material by deposition of barrier coatings.
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Study of barrier and transport properties of polyelectrolytes using diffusion techniques in hydrogels
Valentová, Kristýna ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
This diploma thesis was focused on study of barrier and transport properties of selected polyelectrolytes in hydrogel matrices by using diffusion techniques. The study of these properties was performed in horizontal diffusion cells where is observed the change in diffusion probe concentration over time. Diffusion experiments were performed on an agarose hydrogel with the addition of alginate, hyaluronic acid, polystyrene sulfonate, humic acids and as a model probe rhodamine 6G was used. Important parts of this thesis are also the methods which characterize the substances and hydrogel matrices such as rheology and potentiometric titration. The main aim of this diploma thesis was to investigate the effect of interactions between passing model dye (rhodamine 6G) and the appropriate gel (agarose + polyelectrolyte) on the fundamental diffusion parameters (effective diffusion coefficient, lag time, etc.).
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Barier films based on polyparaxylylene and their properties
Horák, Jakub ; Mazánková, Věra (referee) ; Přikryl, Radek (advisor)
This diploma thesis is focused on preparation and characterization of parylene C barrier properties. The layers were prepared by chemical vapour deposition (CVD). The interest in characterization of those layers is huge mainly because of their possible use in museology for the protection of the museum archives against the corrosion. Chlorinated dimer of para-xylylene was used as a precursor. Polypropylene foils, metal sheets and silica wafers were used as tested substrates for thin film preparation. Polypropylene foils were used for oxygen transmission rate measurements, metal sheets were used for corrosion tests and silica wafers were used for Fourier transform infrared spectroscopy (FTIR), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and stylus profilometry.
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SiOx based barrier coatings
Sedláček, Ondřej ; Dzik, Petr (referee) ; Přikryl, Radek (advisor)
The theme of this thesis is based on the preparation and characterization thin films prepared by methods like a Physical Vapor Deposition, Plasma Assisted Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition. The elementary materials for the preparation of these layers are silicon monooxide powder, melamine and hexamethyldisiloxane. These layers have been prepared with regards to their usage like a barrier coatings with emphasis on poisonous organic substances resistance.. We made a characterization of these films. This characterization is consist of researching of their physical properties (the ability to resist permeation of certain organic compounds), and their chemical composition too. We used to some specific method for these characteristics, for example: FTIR, OTR, ellipsometry, SEM and measuring of the permeation of selected industrial pollutants resistance.
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Multilayer barrier coatings
Sedláček, Ondřej ; Mazánková, Věra (referee) ; Přikryl, Radek (advisor)
The theme of this work is the preparation and characterization of multilayer barrier coatings to polymer and metal substrates based on SiOx and organic molecules. It deals with the determination of their properties in terms of oxygen permeability and corrosion protection. The starting materials for the preparation of these layers are hexamethyldisiloxane, octafluorocyclobutane and 4,12-dichloro[2.2]paracyclophane. These layers have been prepared with regard to their use as barrier coatings for use in archeology, with the focus on corrosion protection of coated items and other specific requirements museums. For these samples was realized characteristic of both in terms of their physical properties – the ability to resist permeation of oxygen and in terms of their chemical composition. The fourier transformation infrared spectroscopy (FTIR), scanning elektron microscopy (SEM), oxygen transmission rate (OTR), contac angle measurement and corrosion testing were used for the above-mentioned characterisations.
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Optimization of the Preparation of Thin Hydrogel Layers Based on Biocompatible Polymers
Vacková, Barbora ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
The aim of this master thesis deals with the optimization of the preparation of thin hydrogel films based on polyvinyl alcohol (PVA) with the possibility of incorporating suitable additives (polyelectrolytes, plasticizers, etc.) into the structure of the prepared film to modify its properties. DEAE-Dextran hydrochloride and polyglutamic acid (PGA) were used as polyelectrolytes. The basic characterization of the properties was performed on modified films, which were compared with pure PVA films. The films were characterized by thickness, swelling ability, barrier properties, tensile properties, specific surface area, antimicrobial tests, and thermogravimetric analysis. The swelling ability of PVA/PGA films was very high, which may be a disadvantage for their use in the packaging industry. Swelling increases the amount of water in the matrix of the PVA film, what leads to a higher growth of microorganisms and to degradation of thin film. The water vapor transmission rate was greatly affected by the addition of a plasticizer. The small specific surface area of the films indicates a smooth surface that promotes good barrier properties. Films with the addition of a plasticizer showed relatively good mechanical properties. The values of tensile strength, elongation and elastic modulus were comparable to commercially available films such as polypropylene (PP) or polyethylene (PE). Based on all experiments, PVA, PVA/DEAEDextran films and their variants with the addition of glycerol as a plasticizer were evaluated as the best candidates for the use of these films as packaging materials. The follow-up work could be dealing with the optimization of PVA films for oxygen permeability. Furthermore, the possibilities of using these films in the packaging industry based on the relative humidity of the environment, could be defined as other interesting area of future research.
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Diagnostics of thin film barrier properties
Horák, Jakub ; Mazánková, Věra (referee) ; Přikryl, Radek (advisor)
This thesis is focused on characterization of the SiOx thin layers properties prepared by plasma enhanced chemical vapour deposition (PECVD). The layers were characterized with regard to its future possible use for the protection of the museum archives against the corrosion. Liquid hexamethyldisiloxane was used as a precursor. Polypropylene foils and silica wafers were used as substrates for thin film preparation. Metal sheets were chosen for corrosion tests. Methods such as permeation rate measurement (oxygen transmission rate - OTR), Fourier transformation infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), ellipsometry and simple corrosion tests of steel sheets coated and uncoated by SiOx thin layer were used for the layer properties characterization.
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Optimization of the Preparation of Thin Hydrogel Layers Based on Biocompatible Polymers
Vacková, Barbora ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
The aim of this master thesis deals with the optimization of the preparation of thin hydrogel films based on polyvinyl alcohol (PVA) with the possibility of incorporating suitable additives (polyelectrolytes, plasticizers, etc.) into the structure of the prepared film to modify its properties. DEAE-Dextran hydrochloride and polyglutamic acid (PGA) were used as polyelectrolytes. The basic characterization of the properties was performed on modified films, which were compared with pure PVA films. The films were characterized by thickness, swelling ability, barrier properties, tensile properties, specific surface area, antimicrobial tests, and thermogravimetric analysis. The swelling ability of PVA/PGA films was very high, which may be a disadvantage for their use in the packaging industry. Swelling increases the amount of water in the matrix of the PVA film, what leads to a higher growth of microorganisms and to degradation of thin film. The water vapor transmission rate was greatly affected by the addition of a plasticizer. The small specific surface area of the films indicates a smooth surface that promotes good barrier properties. Films with the addition of a plasticizer showed relatively good mechanical properties. The values of tensile strength, elongation and elastic modulus were comparable to commercially available films such as polypropylene (PP) or polyethylene (PE). Based on all experiments, PVA, PVA/DEAEDextran films and their variants with the addition of glycerol as a plasticizer were evaluated as the best candidates for the use of these films as packaging materials. The follow-up work could be dealing with the optimization of PVA films for oxygen permeability. Furthermore, the possibilities of using these films in the packaging industry based on the relative humidity of the environment, could be defined as other interesting area of future research.
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Study of barrier and transport properties of polyelectrolytes using diffusion techniques in hydrogels
Valentová, Kristýna ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
This diploma thesis was focused on study of barrier and transport properties of selected polyelectrolytes in hydrogel matrices by using diffusion techniques. The study of these properties was performed in horizontal diffusion cells where is observed the change in diffusion probe concentration over time. Diffusion experiments were performed on an agarose hydrogel with the addition of alginate, hyaluronic acid, polystyrene sulfonate, humic acids and as a model probe rhodamine 6G was used. Important parts of this thesis are also the methods which characterize the substances and hydrogel matrices such as rheology and potentiometric titration. The main aim of this diploma thesis was to investigate the effect of interactions between passing model dye (rhodamine 6G) and the appropriate gel (agarose + polyelectrolyte) on the fundamental diffusion parameters (effective diffusion coefficient, lag time, etc.).
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Barier films based on polyparaxylylene and their properties
Horák, Jakub ; Mazánková, Věra (referee) ; Přikryl, Radek (advisor)
This diploma thesis is focused on preparation and characterization of parylene C barrier properties. The layers were prepared by chemical vapour deposition (CVD). The interest in characterization of those layers is huge mainly because of their possible use in museology for the protection of the museum archives against the corrosion. Chlorinated dimer of para-xylylene was used as a precursor. Polypropylene foils, metal sheets and silica wafers were used as tested substrates for thin film preparation. Polypropylene foils were used for oxygen transmission rate measurements, metal sheets were used for corrosion tests and silica wafers were used for Fourier transform infrared spectroscopy (FTIR), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM) and stylus profilometry.
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