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Modification of polymeric substrates by means of non-equilibrium plasma
Kuzminova, Anna ; Kylián, Ondřej (advisor) ; Čech, Vladimír (referee) ; Novák, Stanislav (referee)
Title: Modification of polymeric substrates by means of non-equilibrium plasma Author: Anna Kuzminova Department: Department of Macromolecular Physics Supervisor of the doctoral thesis: doc. RNDr. Ondřej Kylián, Ph.D. Abstract: Processing of polymeric materials by means of non-equilibrium plasma is a topic that reaches increasing attention, which is due to the wide range of possible applications. As an example can be mentioned processing of polymeric foils used for food packaging, where plasma treatment enables to improve their functional properties (e.g. increase their printability or enhance their barrier properties). In the frame of this PhD. thesis two different strategies suitable for the modification of polymeric materials were followed. The first one was based on treatment of polymers by atmospheric plasma. The main attention was devoted to the investigation of influence of atmospheric pressure plasma on surface properties of 8 commonly used polymers, namely on their chemical composition, morphology and wettability. In addition, it was observed that plasma treatment causes also alteration of their mechanical properties, may lead to their substantial etching and in some cases improves their biocompatibility. The second studied strategy was based on coating of polymers with thin functional...
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Advanced preparation of inorganic (ceramic) particles and nanostructures
Šťastná, Eva ; Martinovou,, Lenku (referee) ; Vojtová, Lucy (referee) ; Částková, Klára (advisor)
Elektrostatické zvlákňování (v literatuře též uváděné jako electrospinning) bylo použito pro příprvu čistě polykaprolaktonových nanovláken a kompozitních nanovláken na bázi polykaprolaktonu s hydroxyapatitovými nanočásticemi. Připravená vlákna byla analyzována za použití rastrovací elektronové mikroskopie. Mechanické vlastnosti vláken byly určeny prostřednictvím zkoušky jednoosým tahem. Testy prokázaly silnou závislost mechanických vlastností vláken na jejich směrovém uspořádání a fázovém složení (především přítomnosti hydroxyapatitových částic). Směrové uspořádání vláken přispělo k výraznému zlepšení napětí při přetržení a celkové tažnosti. Zajímavý jev byl pozorován v případě kompozitních vláken– hydroxyapatitové částice zhoršily mechanické vlastnosti neuspořádaných vláken (napětí při přetržení a celkovou tažnost), ale vliv částic nebyl tak patrný v případě směrově uspořádaných vláken. Povrchové vlastnosti vláken byly modifikovány prostřednictvím nízkoteplotní plazmy. Změny povrchových vlastností vláken byly analyzovány pomocí měření kontaktního úhli a XPS analýzy (rentgenové fotoelektronové spektroskopie). Měření kontaktního úhlu ukázalo výrazný vliv plazmového opracování na povrchovou smáčivost vláken, kdy kontaktní úhel byl zcela neměřitelný. Výsledky analýzy ukázaly vliv plazmového opracování struktur na mikroskopické úrovni – plazmové opracování ovlivnilo pouze polymerní složku vláknitých struktur, zatímco hydroxyapatitové částice nebyly ovlivněny vůbec. Na vybraných strukturách bylo provedeno několik biologických zkoušek. Test v simulovaném tělním roztoku prokázal bioaktivitu kompozitních (polykaprolaton/hydroxyapatit) nanovláken prostřednoctví precipitace fází na bázi fosforečnanů vápenatých na povrchu kompozitních struktur. Následné in-vitro buněčné testy (dle normy ISO 10993-5 a WST-8 test) prokázaly významný pozitivní přínos hydroxyapatitových částic ve vláknitých strukturách, stejně jako kladný vliv plazmového opracování, kdy kompozitní oplazmovaná vlákna vykazovala 1,5násobnou bioaktivitu v porovnání s neplazmovanými čistě polykaprolaktonovými vlákny.
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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.
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Nanoparticle treatment technology to improve their dispersibility for use in cemt composites
Závacký, Jakub ; Sťahel,, Pavel (referee) ; Hela, Rudolf (advisor)
The diploma thesis deals with the possibility of using the addition of nanoparticles to improve the properties of cement composites. The theoretical part summarizes the findings of research in this area with a focus on methods of dispersion of nanoparticles and their treatment for use in cement composites. The experimental part focuses on the comparison of methods of dispersion and plasma treatment of reduced graphene oxide (rGO) nanoparticle solutions from the point of view of the agglomeration process. During this work, a method of systematic optical/visual monitoring of sedimentation/agglomeration was developed to complement sophisticated methods such as spectrophotometry (UV/Vis) and electron microscopy (SEM). Furthermore, the effect of the addition of rGO on the properties of cement mortar, in the form of aqueous solutions prepared by the dispersion methods determined in the previous section, was investigated.
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Plazmové opracování porézních povrchů
Vaidulych, Mykhailo ; Hanuš, Jan (advisor) ; Pavlík, Jaroslav (referee) ; Tichý, Milan (referee)
Title: Plasma treatment of porous structures Author: Mykhailo Vaidulych Department / Institute: Department of Macromolecular Physics Supervisor of the doctoral thesis: Prof. Assist. Jan Hanuš, Ph.D., Department of Macromolecular Physics Abstract: The thesis is focused on the implementation of low-temperature plasma for the modification of porous materials. Two main strategies are involved: functionalization through the deposition of functional nanocomposite coatings and low-pressure plasma etching. In the first case, a gas-phase step-by-step deposition process based on the combination of deposition of nanoparticles and thin films was developed to obtain super-wettable nanocomposite coatings on filtration membranes. It was shown that the deposition parameters of thin films and particles of plasma polymer can tune the wetting characteristic of the membranes whereas embedding copper nanoparticles endows them with antibacterial properties. As a result, highly efficient superhydrophobic/superoleophilic and smart superamphiphilic membranes were successfully fabricated for oil/water separation. Plasma processing in the atmosphere of argon, oxygen or nitrogen was utilized to modify hard metal/polymer nanocomposites (Ag/a-C:H) with potential to be used as functional coatings for bone implants. An anisotropic etching...
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Plasma treatment impact on physical and chemical properties of polymeric fibers
Hlůžek, R. ; Prošek, Z. ; Trejbal, J. ; Fládr, J. ; Potocký, Štěpán
Presented work focuses on chemical and physical properties of plasma modified polymeric macro-fibers. Polyethylene terephthalate (PET) and polypropylene (PP) fibers having approx. 300 mu m in diameter were modified using cold oxygen plasma in order to achieve their surface changes needed for durable bond and adhesion with cement matrixes. A duration of plasma modification differed between 5 to 480 seconds, where an effect of the treatment was examined. Fiber surfaces chemical changes were researched via wettability measurement with demineralized water (the measurement was repeated immediately and after 1, 7 and 30 days to find out the changes stability). Physical changes were studied by means of weight balance (determination of weight loss) and tensile strength tests. It was found that wettability was enhanced significantly - up to two times, while mechanical properties of treated fibers decreased only slightly.\n
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Performance of cement composites reinforced with surface-modified polypropylene micro-fibers
Antoš, J. ; Dejdar, L. ; Trejbal, J. ; Prošek, Zdeněk
This paper focuses on the mechanical properties investigation of cement pastes reinforced with surface treated polymer fibers. The cement matrix was composed of Portland cement (CEM I 42.5 R, w/c ratio equal to 0.4). Two polypropylene fiber types (micro-and macro-fibers) were used as randomly distributed and oriented reinforcement in volume amount of 2 %. The fibers were modified in the low-pressure inductively coupled cold oxygen plasma in order to enhance their surface interaction with the cement matrix. The investigated composite mechanical properties (load bearing capacity and response during loading) were examined indirectly by means of four-point bending mechanical destructive tests. A response of loaded samples containing treated fibers were compared to samples with reference fibers. Moreover, cracking behavior development was monitored using digital image correlation (DIC). This method enabled to record the micro-cracks system evaluation of both fiber reinforced samples.\n
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The Influence of Surface Treatment and Activation of Thin Film Composite Membranes with Plasma Discharge and Determination of Their Physicochemical Properties.
Slepička, P. ; Setničková, Kateřina ; Petrusová, Zuzana ; Slepičková-Kasálková, N. ; Kolská, Z. ; Siegel, J. ; Jansen, J. C. ; Esposito, E. ; Fuoco, A. ; Švorčík, V. ; Izák, Pavel
In this work we have focused on the surface treatment and activation of membranes (73 AC and 82 V) with plasma discharge and determination of their physicochemical properties. The surface morphology, wettability, zeta potential of pristine and plasma- treated membranes were tested and compared.
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Modification of polymeric substrates by means of non-equilibrium plasma
Kuzminova, Anna ; Kylián, Ondřej (advisor) ; Čech, Vladimír (referee) ; Novák, Stanislav (referee)
Title: Modification of polymeric substrates by means of non-equilibrium plasma Author: Anna Kuzminova Department: Department of Macromolecular Physics Supervisor of the doctoral thesis: doc. RNDr. Ondřej Kylián, Ph.D. Abstract: Processing of polymeric materials by means of non-equilibrium plasma is a topic that reaches increasing attention, which is due to the wide range of possible applications. As an example can be mentioned processing of polymeric foils used for food packaging, where plasma treatment enables to improve their functional properties (e.g. increase their printability or enhance their barrier properties). In the frame of this PhD. thesis two different strategies suitable for the modification of polymeric materials were followed. The first one was based on treatment of polymers by atmospheric plasma. The main attention was devoted to the investigation of influence of atmospheric pressure plasma on surface properties of 8 commonly used polymers, namely on their chemical composition, morphology and wettability. In addition, it was observed that plasma treatment causes also alteration of their mechanical properties, may lead to their substantial etching and in some cases improves their biocompatibility. The second studied strategy was based on coating of polymers with thin functional...
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Effect of Plasma Oxidation of Carbon Working Electrode on Its Electrochemical Response
Koporec, Lukáš
Screen-printed electrochemical sensors are very perspective because they are much smaller than common electrodes used in electrochemistry, portable, ecological and can be very easily modified in order to increase their sensitivity and selectivity for specific analytes. In this study, plasma treatment was used to modify the carbon working electrode of a screen-printed threeelectrodes system. Plasma treatment was performed using RF plasma discharge in argon/oxygen atmosphere. The plasma modified electrodes exhibited considerable enhancement in electrocatalytic activity towards studied electroactive compounds.
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