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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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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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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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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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