The aim of the diploma thesis is generation of active particles in plasma activated water (PAW) using a low-temperature plasma discharge. In this work I focus on the determination of hydrogen peroxide, nitrites and nitrates as active particles. The practical part is focused on a specific case of use of a plasma discharge in selected electrolytes dissolved in an aqueous solution. Here, three phosphates, differing in the number of acidic hydrogens, were selected for each experiment, and sodium chloride and tap water were compared for comparison. Phosphates were selected for their stable pH during plasma discharge in solution to monitor the effect of pH. The experiments were focused on investigating the stability of active particles in PAW, under which conditions is the highest production rate of these particles and what effect the pH value has on the result. It was found that hydrogen peroxide is generated the most in an alkaline environment but shows better stability in neutral. The concentration of generated nitrites is not high, but it shows stability, regardless of the polarity of the main electrode used for PAW generation. Nitrites were generated the most in alkaline environment and nitrates in acidic environment. One of the conclusions is that nitrates are not a very stable particle in PAW. Thanks to the activation and oxidation properties of plasma activated water, this method can be used in medicine or agriculture

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.

Title: Nano-structured multicomponent plasma polymers for controlled immobilization of biomolecules Author: Iurii Melnichuk Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, Ph.D. Abstract: The aim of this thesis is to highlight the feasibility of tailored nano- structures in functionalizing surfaces for biointerfacial interactions. Development of new techniques for the production of nanoscaled biomaterials can be of use in a variety of medical and biological applications, e.g. biosensors, microarrays, drug sensors, implants, blood-contacting devices. This thesis first examines the early stages of nano-structured thin film growth fabricated by vapor phase deposition of poly(ethylene). We discuss island growth within a framework of rate equation theory, dynamic scaling theory and capture zone distribution. In a second stage, we test dielectric barrier discharge to activate PE nano-pattern for covalent immobilization of proteins. Finally, we assess cell behavior on surfaces in dependence on morphology and the presence of cell adhesive protein tropoelastin. We employ plasma polymerization to produce ultrathin hydrocarbon layer capable of protein anchoring. The thesis findings for the first time manifest the critical...

L’environnement réactif du plasma constitue un outil puissant dans la science des matériaux, permettant la création de matériaux innovatifs et l'amélioration de matériaux existants qui ne serait autrement pas possible.Le plasma fournit simultanément des fluxes de particules chargées, des molécules chimiquement actives, des radicaux, de la chaleur, des photons, qui peuvent fortement influencer les voies d'assemblage à différentes échelles temporelles et spatiales, y compris à l’échelle atomique.Dans cette thèse de doctorat, des méthodes tenant pour base des plasmas micro-ondes ont été utilisées pour la synthèse de nanomatériaux de carbone, y compris graphène, graphène dopé à l'azote (N-graphène) et structures de type diamant.À cette fin, ce travail est lié à optimisation de la synthèse de nanostructures 2D du carbone, comme graphène et N-graphène par la poursuite de l'élaboration et du raffinement de la méthode développée en Plasma Engineering Laboratory (PEL). La synthèse de graphène de haute qualité et en grandes quantités a été accomplie avec succès en utilisant des plasmas d'Ar-éthanol à ondes de surface dans des conditions de pression ambiante. De plus, le N-graphène a été synthétisé par un procédé en une seule étape, de l'azote a été ajouté au mélange d’Ar-éthanol, et par un procédé en deux étapes, en soumettant des feuilles de graphène préalablement synthétisées ont été exposées à un traitement plasma argon-azote à basse pression. Les atomes d'azote ont été incorporés avec succès dans le réseau de graphène hexagonal, formant principalement liaisons pyrroliques, pyridiniques et quaternaires. Un niveau de dopage de 25 at.% a été atteint.Différents types de nanostructures de carbone, y compris du graphène et des structures de type diamant, ont été synthétisées au moyen d'un plasma d’argon en utilisant du méthane et du dioxyde de carbone comme précurseurs du carbone.De plus, des plasmas à couplage capacitif ont également été utilisés pour la fonctionnalisation du graphène et pour la synthèse de nanocomposites, tels que les composites de Polyaniline (PANI)-graphène. Les utilisations potentielles de ces matériaux ont été étudiées et les deux structures ont démontré avoir des attributs remarquables pour leur application aux biocapteurs. / Plasma environments constitute powerful tools in materials science by allowing the creation of innovative materials and the enhancement of long existing materials that would not otherwise be achievable. The remarkable plasma potential derives from its ability to simultaneously provide dense fluxes of charged particles, chemically active molecules, radicals, heat and photons which may strongly influence the assembly pathways across different temporal and space scales, including the atomic one.In this thesis, microwave plasma-based methods have been applied to the synthesis of advanced carbon nanomaterials including graphene, nitrogen-doped graphene (N-graphene) and diamond-like structures. To this end, the focus was placed on the optimization of the production processes of two-dimensional (2D) carbon nanostructures, such as graphene and N-graphene, by further elaboration and refinement of the microwave plasma-based method developed at the Plasma Engineering Laboratory (PEL). The scaling up of the synthesis process for high-quality graphene using surface-wave plasmas operating at atmospheric pressure and argon-ethanol mixtures was successfully achieved. Moreover, N-graphene was synthetized via a single-step process, by adding nitrogen to the argon-ethanol mixture, and via two-step process, by submitting previously synthetized graphene to the remote region of a low-pressure argon-nitrogen plasma. Nitrogen atoms were usefully incorporated into the hexagonal graphene lattice, mainly as pyrrolic, pyridinic and quaternary bonds. A doping level of 25% was attained.Different types of carbon nanostructures, including graphene and diamond-like nanostructures, were also produced by using methane and carbon dioxide as carbon precursors in an argon plasma.Additionally, capacitively-coupled radio-frequency plasmas have been employed in the functionalization of graphene and in the synthesis of Polyaniline (PANI)-graphene composites. The potential uses of these materials were studied, with both showing favourable characteristics for their applicability in biosensing applications.

Plasma treatment of polypropylene fibers presents a new progressive method, how to increase the utility properties of these fibers. The thesis is focused on verifying the effect of surface treatment of polypropylene fibers in concrete with low-temperature plasma discharge in the normal atmosphere. The paper describes the procedure for treatment of polypropylene fibers with low-temperature plasma and evaluate the impact of this adjustment on the volume changes of cement composites. It should also be emphasized that the thesis is focused on the initial volume changes, ie volume changes in the early stages of solidification and only for your own mixture, which is not considered an external load. Subsequently, the experimental verification of the effect of the addition made commercially available fibers and fibers treated plasma volume changes to a selected physico-mechanical properties of the test compounds.

This diploma thesis is focused on the plasma surface treatment of historical glass from the 18th and 19th centuries by low temperature electrical discharges in solutions of sodium chloride and potassium carbonate and finding the most suitable settings of conditions for the surface cleaning. Stainless steel electrode and a specially designed electrode system with wolfram wire in the quartz glass capillary were used for the generation of discharge using an audio frequency power supply. Each line of samples was made from one piece of historical glass that was cut to smaller pieces. All cleaned samples were photographed before and after the cleaning so the possible changes of the cleaned area could be visually compared. Then the samples were analysed by LA-ICP-MS (line scanning of surface), where was analysed the cleaned area of samples, and values were compared to the analysis of the reference sample that was not cleaned. Examined isotopes of elements were selected on the basis of the supposed composition of glass, corrosion products, and soil at the place of discovery. Analyses were standardized by NIST 610. Acquired values were transferred to oxides. The most important oxides (Na2O, MgO, SiO2, P2O5 a K2O) were chosen for deciding the most effective cleaning settings. It was decided that the most effective setting for cleaning was the one where the biggest difference of values between sample and reference occurred. Four series of these solutions were compiled and one parameter was changed for each of them. Solutions and their conductivity, frequency of the power supply, and time of cleaning were chosen as changing values. Three samples of different times of cleaning were cleaned without interruption. The time of cleaning was split into intervals of 30 seconds of cleaning and 1 minute of non-action for another two samples of this series. In this way we were trying to find out if the following surface analysis will be influenced by the diffusion of the particles into the sample, or not. The frequency of power supply was recorded and its dissipated power was calculated for each measurement. Emission spectra of a series of different solution conductivity were measured before cleaning of samples. Measurement of OES was made with the ignition of discharge so the active species of plasma were shown in spectra. These species are probably participating in the cleaning process of glass. Emission spectra were also measured after cleaning to find out if values of active species were changed or unknown spectral lines appeared. These lines should be from dirt and corrosion products that were cleaned from the surface of the glass. It was found out that the most effective cleaning of sample 1 (series where the conductivity of the NaCl solution was changed) was done in a solution of conductivity 900 S/cm. The most effective cleaning of sample 4 and sample 7 (series where the conductivity of the K2CO3 solution was changed) was done in a solution of conductivity 600 S/cm. The most effective cleaning of sample 6 (series where the frequency was changed) was done at frequency = (15200 ± 30) Hz. The most effective cleaning of sample 5 (series of different cleaning times) lasted seven minutes without time delay. The future research it should be appropriate to try a combination of these most effective cleaning settings on the surface of more samples, so the finding of this thesis will be confirmed.

The aim of the Master thesis is the investigation of the influence of microwave discharge for skin wound healing. Microwave discharge used for this work was argon microwave plasma generated by the surface wave and direct vortex torch. The theoretical part is focused on basic information about plasma and processes that occur in plasma discharge under specific conditions. Plasma generates various active particles such as hydroxyl radicals, nitric oxide radicals, excited nitrogen molecules, atomic nitrogen, argon and oxygen. All of these particles together with plasma generated photons are usable in biomedical applications and summary of them is shown in the theoretical part. The experimental part is focused on the comparison of torch discharge and microwave plasma generated surface wave in skin wound healing. The model wounds on laboratory mousses were treated by plasma and wound healing was examined during 3 weeks after the plasma treatment. Both plasma systems showed healing acceleration. Application of torch discharge was proved to be the most effective method in the healing of skin defects. Additionally, determination of active particles was taken by optical emission spectroscopy. Based on these measurements, plasma parameters were determined: electron temparutare, rotational and vibrational temperatures. To determine role of different plasma active species, the treatment of indigo coloured artificial skin model was treated under various conditions by both plasma systems. Results show that the direct interaction between plasma particles is the main effect, role of radiation, only, is more or less negligible. Finally, the plasma vortex system was visualized using fast camera at selected powers and gas flows.

This diploma thesis was focused on the possibility of using a plasma nozzle to accelerate the wound healing process. The benefits of using low-temperature plasma in medicine or biomedical applications are known from many studies, and low-temperature plasma is already used to sterilize medical devices, materials or surgical instruments. Some studies also report a high potential of usinh plasma nozzle in the treatment of skin wounds. In the experimental part of this work, an in vitro wound healing test was performed using two different low-temperature plasma sources. Source No. 1 was a surface wave microwave discharge and source No. 2 was a torch microwave discharge. An in vitro scratch healing test was performed on a monolayer of HaCaT keratinocytes and testing was performed using various parameters. The influence of the plasma treatment time was monitored, as well as the influence of the plasma discharge power and also the influence of the argon working gas flow. Especially when using a torch microwave discharge, faster wound healing was recorded at most of the parameters used compared to the control. Thus, it can be said that this source appears to be potentially suitable for faster wound healing. Furthermore, in the work using the MTT cytotoxicity test, the viability of skin cells after their plasmination was also monitored using the same conditions as in the in vitro wound healing test. When performed in the standard MTT assay, none of the settings or sources used showed any cytotoxic effects on keratinocytes. LDH cytotoxicity tests were also performed concurrently to verify the accuracy of the MTT assays. The results of both tests agreed and the use of low-temperature plasma in skin treatment can be considered as safe. Overall, the results show that the plasma nozzle can find use in medicine in the healing of skin wounds and chronic defects as a potentially fast, inexpensive and effective method.