|
|
Surface morphology of a-CSi:H films prepared from tetravinylsilane in low-temperature plasma
Křípalová, Kristýna ; Pálesch, Erik (referee) ; Čech, Vladimír (advisor)
This bachelor thesis is focused on the surface morphology of a-CSi:H films. Films were prepared by plasma-enhanced chemical vapor deposition (PECVD) on silicon wafers using plasma discharge. Tetravinylsilane (TVS) precursor was used for deposition. The set of samples deposited at different effective power (2-150 W) and a thickness of about 0.6 µm was characterized to investigate their surface properties. Atomic force microscopy was used for characterization of surface morphology. Obtained results were used for evaluation of surface roughness and assessment of the effect of the film growth dynamics on the surface topography.
|
|
|
Surface topography of a-CSi:H films deposited by continuous wave PECVD
Blažková, Naďa ; Pálesch, Erik (referee) ; Čech, Vladimír (advisor)
The thesis describes surface topography of a-CSi:H films deposited by continuous wave plasma enhanced chemical vapor deposition (PECVD) based on tetravinylsilane monomer (TVS). Thin films are completely used in many fields of modern technologies and their physical and mechanical properties are affected by thin film preparation techniques. In this thesis the thin films were deposited by PECVD method on silicon wafers with the pure TVS monomer. Deposited samples were topographically described and analyzed using atomic force microscopy (AFM). The main characteristics which were described are RMS roughness, autocorrelation function and a size distribution of grains on the thin film surface. Analysis was realized with two sets of samples with different powers and thickness. The main results were statistically evaluated like a mixture of object on the surface prepared in different deposition conditions.
|
|
|
Chemical structure of silicon-based thin films
Olivová, Lucie ; Franta, Daniel (referee) ; Čech, Vladimír (advisor)
This bachelor thesis deals with the characterization and preparation of thin polymer films deposited on silicon wafers by plasma-enhanced chemical vapour deposition. The main part of the work is background research in the field of plasma polymerization and infrared spectroscopy. Thin polymer films based on tetravinylsilane and tetravinylsilane with the addition of mixed gas (argon) were prepared in the experimental part. The prepared thin films of plasma polymers were characterized by the selected spectroscopic technique - infrared spectroscopy. Based on the evaluation of transmission infrared spectra, the chemical structure of the deposited polymer films was determined. The determined chemical structures of the prepared films were observed with respect to the deposition conditions and hence the possibility to prepare tailored films for a variety of applications.
|
|
|
Shear strength of the fiber-reinforced polymer composite
Jurko, Michal ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
The diploma thesis deals with the study of Inter-Laminar Shear Strength (ILSS) of polymer composites, based on unsaturated polyester resin with unidirectionally oriented basalt or glass fibers. The basis of the experimental part is the preparation of composite samples with different types of surface treatment of a fibers (a reinforcement) as well as the surface treatment itself. The untreated, the commercially treated fibers and the plasmatreated fibers used as reinforcement in the polymer composites were analysed by a short beam shear test and their ILSS was determined. The effect of various deposition conditions during Plasma-Enhanced Chemical Vapour Deposition (PECVD) on the value of ILSS of the composite with originally unsized glass or basalt fibers was studied. The impact of aging on the interlaminar shear strength of the composites was investigated for commercially treated glass fibers. The Scanning Electron Microscopy (SEM) is also used in the thesis together with the Energy Dispersive Spectroscopy (EDS). Based on all the results a proposal was made to correct and improve the deposition conditions and thus improve the interphase to achieve the required shear properties of polymer composites.
|
|
|
Functional organic-inorganic nanostructures
Kelíšek, Petr ; Zmeškal, Oldřich (referee) ; Čech, Vladimír (advisor)
Diploma thesis deals with preparation of multilayered organic-inorganic nanostructures via PECVD technology and analysis of optical properties of these layers by spectroscopic ellipsometry. The theoretical part handles the definition of thin layers, layered and gradient nanostructures, plasma enhanced chemical vapor deposition and principles of spectroscopic ellipsometry. In the experimental part, used materials and chemicals are described, afterwards follow a complete description of the apparatus used for sample preparation and a description of the sample preparation procedure. The results part consists of methodology of preparing material models necessary for ellipsometric measurements and evaluation of optical properties of deposited nanolayers.
|
|
|
Plasmachemical processing of fibrous reinforcements for polymer composites
Knob, Antonín ; Lapčík, Ĺubomír (referee) ; Čech, Vladimír (advisor)
The diploma thesis is aimed at coating of glass fibers using tetravinylsilane as a monomer by Plasma-Enhanced Chemical Vapor Deposition (PECVD). The surface modified fibers were used as reinforcements for unsaturated polyester resin to form composites of controlled interphase. Chemical and mechanical properties of thin films were controled by the effective power. Determination of fiber-matrix adhesion and an influence of polymer-interface on mechanical properties of composites were characterized by Scanning Electron Microscopy (SEM) and microindentation technique using Interfacial Testing System (ITS) enabling to measure the interfacial shear strength.
|
|
|
Plasma chemical deposition of thin fluorocarbone films
Veverková, Radka ; Přikryl, Radek (referee) ; Krčma, František (advisor)
Deposition of thin films is one of the most widespread applications used for the changes of surface properties of various materials. This diploma thesis is focused on diagnosing of thin film generated by a PECVD technique. The capacitively coupled RF discharge at low pressure was used for the thin films deposition using tetrafluoromethane (CF4) with addition of hydrogen (H2) as a precursor. The aim of the work was the search of optimal conditions for a hydrophobic thin layer preparation on the surface of polymer NOA. The depositions were performed in continuous and pulsed mode with different duty cycle. The discharge was monitored using optical emission spectroscopy and in situ mass spectrometry. Thin films structure and properties were characterized using water contact angle measurements, X-ray photoelectron spectroscopy, infrared spectroscopy and optical ellipsometry. The influence of varying power, gas mixture composition and discharge mode were investigated. Water contact angle was the highest for a deposition in a continuous mode. Decomposition processes inside the reactor were observed by using mass spectrometry and optical emission spektrokopie. X-ray photoelectron spectroscopy provided information about the chemical bonds represented on the surface of sample. These were mainly C – C/C – H, C – O, O = C - O groups for sample without layer. Other chemical bonds were observed after the deposition. These were mainly C – CF, CF2 and CF3 groups. The film thickness of about 8,2 nanometers was measured by optical ellipsometry. The obtained results may be used as a fundament for further more advanced study of plasma chemically prepared thin fluorocarbon films and their properties.
|
|
|
Polymer composites with controlled interphase
Zvonek, Milan ; Knob, Antonín (referee) ; Čech, Vladimír (advisor)
Cieľom diplomovej práce je príprava polymerných kompozitov vyztužených sklenenými vláknami s riadenou medzifázou za použitia metódy plazmochemickej depozície z plynnej fáze a monomeru tetravinylsilanu. Teoretická časť je zameraná na literárnu rešerš o plazme, plazmovej polymerácií, tenkých vrstvách a kompozitoch. Experimentálna časť popisuje použité materiály a aparaturu použitú na povrchovú modifikáciu sklenených vlákien a prípravu vláknom vyztužených kompozitov. Povrchová úprava sklenených vlákien prebiehala za rôznych depozičných podmienok. Chemické a mechanické analýzy vytvorenej medzivrstvy prebiehali za použitia FTIR spektrometrie a vrypového testu. Vliv povrchovej úpravy bol zistený pomocou získanej interlaminárnej šmykovej sily použítím testu krátkych trámečkov.
|
|
|
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.
|
|
|
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.
|
guest ::
