|
|
Titania mesoporous films fabricated by material printing
Chludilová, Markéta ; Drbohlavová, Jana (referee) ; Dzik, Petr (advisor)
Thesis deals with the creation of thin layers of a porous titanium dioxide. The solutions for the formation of thin layers were prepared using a solgel method by mixing TTIP, polyethylene glycol of molecular weight 1500 and dimethyl, layers were subsequently printed by material printer to glass substrate and calcinated at 450 °C for 2,5 hours. Optical and SEM microscopy was used to observe structure of individual layers. Samples, that showed the greatest porosity, were subsequently studied by electrochemical measurments and by photocatalytic aktivity determined via hydroxylation of coumarin.
|
|
|
Titania suspensions for material printing
Svoboda, Tomáš ; Drbohlavová, Jana (referee) ; Dzik, Petr (advisor)
This bachelor‘s thesis deals with the preparation of stable suspensions of titanium dioxide applicable for material printing. A wide range of dispersive environments stabilizing the nanoparticles of titanium dioxide was investigated. Commercially available aqueous dispersion and dry titania powder was used as the source of TiO2.The properties of prepared suspensions were evaluated and the most suitable suspension was used for material printing. This thesis focused on suspension‘s stability, sizes of particles dispersed in them, and in their rheological behavior. Furthermore, we analyzed the studied the properties of printed layers by SEM, optical microscopy, DLS and analytical centrifuge. We also evaluated the photocatalytic activity by monitoring the oxidation rate of coumarin to 7-hydroxycoumarin.
|
|
|
Titanium dioxide blocking layers fabricated by material printing
Lásko, Ondřej ; Pospíšil, Jan (referee) ; Dzik, Petr (advisor)
In this theses TiO2 blocking layers were fabricated using material inkjet printing and spincoating methods. These layers were then analyzed using cyclic voltammetry to find any defects and to determine the type of those defects. We found that layers of over 120 nm made using ITO glass and spincoating method had the best blocking capabilities. Blocking layers prepared using FTO glass were underperforming greatly throughout the whole experiment. We also achieved good results with material ink jet printing. The best results out of all printed samples were achieved with DPI of 635, although these layers also had problem with the electrolyte rising through microscopic pores in the layer thus changing the results.
|
|
|
Properties of titania layers fabricated from ball-milled colloid dispersions
Rajmonová, Anna ; Klusoň, Petr (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with changing properties of the thin layered titanium dioxide dispersion depending on the time of ball-milling. Titanium dioxide is immobilized on glass or conductive glass using the spin-coating method and the prepared thin layers are then characterized by various analytical methods. All of used analytical methods are described in theoretical and experimental sections, these methods include scanning electron microscopy, profilometry, dynamic light scattering, integrating sphere, ellipsometry, BET isotherm, voltammetry and chronoamperometry. At the summary of this diploma thesis is described how the properties of titanium dioxide thin layers change during ball-milling process.
|
|
|
Investigation of Methacrylated PVAl Photochemical Crosslinking
Králová, Marcela ; Čeppan, Michal (referee) ; Dzik, Petr (advisor)
This diploma thesis deals with a detailed study of photoinitiated radical polymerization of macromers base on PVAl containing lateral GMA moieties. The main goal is the evaluation of the influence of photoinitiator concentration, polymerisable group content and/or other aditives on the polymerisation rate. Other goals include the study of possible influencing the photochemical speed by lowering the glass transition temperature, compatibility with various photoinitiators etc. Attention is also paid to the study of prepared 3D polymeric networks properties
|
|
|
Accelerated testing of lightfastness of indoor furniture coatings
Kulhánková, Michaela ; Drábková, Klára (referee) ; Dzik, Petr (advisor)
This bachelor thesis deals with the study of the current methods of testing and evaluation of lightfastness of interior paints. Their fading is caused mainly by the influence of solar radiation. The first part provides the basic information needed to understand the experiment. In the second part, wood samples with various white varnishes and coatings were subjected to accelerated testing of lightfastness. The experiment was performed by exposing these samples to xenon lamp through the window glass filter in the solar chamber. Changes in the color of the samples were evaluated based on the measurement of the reflection spectra from which the colorimetric quantities were calculated and then displayed in the color space CIE 1976 L*a*b*. The conclusion was focused on the final real life of the samples, their mutual comparison and evaluation of the most suitable materials.
|
|
|
Photoelectrochemical properties of titanium dioxide doped by metals
Vičarová, Monika ; Drbohlavová, Jana (referee) ; Dzik, Petr (advisor)
This thesis deals with the optimization of materials and processes for making layers of titanium dioxide enriched with metal nanostructured aggregates. These layers have a plasmonic effect in visible light radiation. Gold-doped titanium dioxide thin films were applied to the FTO glass substrate by spin-coating method and calcined at 450 ° C for 30 minutes. Two forms of titanium dioxide and two different gold precursors were used to make the layers. The structure of the layers was observed by optical and SEM microscopy. The photoelectrochemical properties of the prepared layers were studied by electroanalytical methods linear sweep voltammetry and chronoamperometry.
|
|
| |
|
|
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.
|
|
|
Hybrid biopolymer composites for 3D printing applications
Menčík, Přemysl ; Bakoš, Dušan (referee) ; Dzik, Petr (referee) ; Jančář, Josef (advisor)
This dissertation work deals with the thermic and the mechanical behavior of plasticized bio-plastics and bio-composites for the 3D printing applications. The influence of plasticizer chemical structure on thermic and mechanical properties of plasticized polymeric blends from the poly-3-hydroxybutyrate and the poly lactic acid was investigated. Used plasticizers are based on derivative of citric acid. The influence of plasticizers on polymeric matrix and their compatibility was estimated by gear torque rate of melt mixer, respectively rate of plasticizer migration from the material during higher temperature. The plasticizer structure influence on the glass transition temperature and on the kinetics of crystallization of plasticized material was investigated by modulated differential scanning calorimetry. The behavior of material during 3D printing was also observed. Mechanical properties of printed samples, especially their elongation at break, were determined by tensile tests. The largest softening effect was observed using tributylcitrate plasticizer, where the glass temperature decreased by 35 °C and elongation at break increased by 150% compared to non-plasticized reference material. This plasticized polymeric blend showed also sufficient 3D printing properties and was used as the matrix for composites in the next part of this work. Composites were filled by kaolin, limestone, halloysit, fumed silica, talc, magnesium hydroxide and chopped flax fibers. Particle distribution in composites in dependence of used surface treatment of filler was observed by scanning electron microscopy. The influence of composite filler on rheological properties, crystallization kinetics and thermal stability of composites, was observed by viscometry and differential scanning calorimetry. Their mechanical properties and heat deflection temperature were observed on samples prepared by 3D print. Kaolin in composite material showed homogeneous particle distribution and insignificant nucleation effect and influence on thermic stability. Composite filled by kaolin also showed 18% smaller warping during 3D printing compared to non-filled reference. Consequently kaolin was evaluated as suitable inorganic filler for bioplastic composite intended for 3D print and this composite was used in the following part of this thesis. Method of mathematical prediction of Young's modulus was described for composite samples prepared by 3D print. Composites filled by one type of filler – kaolin, or limestone, resp. by combination of both fillers were investigated on the basis of the micromechanic Halpin-Tsai model modified by the semiempiric multiparametric Cerny's equation. Additive and combinational method of Young's modulus evaluation is used for composites with hybrid filling. Deflection of measured and theoretical Young's modulus value of composite filled with kaolin was decreased by established correction from 21% to 1% and for composites filled with limestone from 13% to 9%. In this manner it is possible to predict the Young's modulus of the samples prepared by 3D print.
|
guest ::
