The field of nanoparticle preparation is nowadays rapidly evolving. Most of the ap- proaches can be classified as wet chemistry techniques. On the other hand, gas aggrega- tion sources offer an alternative, purely physical approach of how to fabricate nanoparti- cles in a controlled and reproducible manner. Many kinds of nanoparticles were already produced in this way, e.g. metallic, metal oxides or plasma polymer nanoparticles. Moreover, as it was demonstrated in recent studies, even heterogeneous nanoparticles by combining more types of materials may be produced by such sources. Among them, an increasing interest is devoted to the metal/plasma polymer nanoparticles. Concerning the production of metal/plasma polymers nanoparticles, the majority of so far published studies focused on the nanoparticles with metallic cores surrounded by a plasma polymer overcoat. Because of this, we decided to investigate a novel two- step deposition procedure for the production of metal/plasma polymer nanoparticles with inverse structure, i.e. nanoparticles with plasma polymer cores covered by metal. This method is based on the gas aggregation technique for plasma polymer nanoparticle fabrication (C:H:N:O in this study) followed by subsequent in-flight coating by sputtered metal (silver, copper and titanium). The production...

Dentre os principais avanços na área de ciência ou tecnologia dos materiais podemos ressaltar as atuais técnicas de produção, manipulação e análise de estruturas de tamanho muito reduzido, os quais possuem propriedades físicas (magnéticas, eletrônicas e óticas) diferentes das apresentadas pelos mesmos materiais em estruturas maiores. Nanopartículas (NPs) de metais nobres, principalmente ouro e prata, estão sendo utilizadas e incorporadas em diversas tecnologias que tiram proveito de suas características óticas ou condutivas Neste trabalho apresentamos uma metodologia de preparação de NPs de metais nobres, com a possibilidade de incorporá-las em um material dielétrico. As amostras, produzidas a partir da técnica de agregação gasosa, foram preparadas em um gerador de NPs, construído em um dos canhões de um sistema de magnetron sputtering comercial (AJA Internacional). No gerador, átomos são removidos do alvo e termalizados pelo fluxo do gás de trabalho, se condensando na forma de NPs. As NPs são extraídas do gerador aerodinamicamente e seguem em direção ao substrato. Utilizando um dos outros canhões do nosso sistema de sputtering podemos codepositar as NPs produzidas em uma matriz dielétrica ou metálica. Podemos também depositar camadas de filmes finos sobre o material produzido pelo gerador de NPs. As amostras de nanopartículas de ouro e prata produzidas foram caracterizadas a partir de técnicas de microscopia eletrônica de varredura (MEV), retroespalhamento Rutheford (RBS), espectrofotometria de UV-Visível e microscopia ótica em campo próximo (SNOM). A partir das imagens de MEV, podemos inferir a presença da matriz dielétrica a partir da separação das NPs e essa presença pode ser confirmada pela análise dos resultados de RBS. Por fim a análise do espectro de absorbância das amostras em conjunto com as imagens de SNOM demonstrou o comportamento plasmônico das amostras produzidas, sobretudo das NPs codepositadas em matriz dielétrica. / In the midst of main advances in material science and technology we can highlight the new techniques of preparation, manipulation and analyses of structures of very small size. They have physical properties (magnetic, electronic and optical) different from those presented by the same material, but in bigger dimension. Noble metal nanoparticles, mainly gold and silver, are incorporated into various technologies in order to take advantage of their optical or electric properties. In this work, we present a technique to produce noble metal nanoparticles by a physical method that also permits to imbed them in a dielectric material matrix. The samples, produced using the gas aggregation technique, were prepared in a nanoparticle gun, developed on one of the guns of a commercial magnetron sputtering system (AJA International). In the nanoparticles generator, atoms are removed from the target and thermalized by the flow of the sputtering working gas, and they are also condensed to form the nanoparticles. The nanoparticles are extracted from the generator aerodynamically and then they proceed to the substrate. Using another gun of the sputtering system we can deposit the nanoparticles produced in a dielectric or metallic matrix. We can also deposit under and capping layers of thin films on the nanoparticles layer produced. The samples of gold and silver nanoparticles produced were characterized by scanning electron microscopy (SEM), Rutherford backscattering analysis (RBS), UV-Visible spectrophotometry and near field optical microscopy (SNOM). In the SEM images, from the distribution and morphology of the nanoparticles it was possible infer the presence of the dielectric matrix, and this was also confirmed by the RBS measurements. Finally, absorbance spectrum of the samples together with the SNOM images have demonstrated the plasmonic character of the samples produced, specially for the NPs co-deposited in the dielectric matrix.

Nos últimos anos novas propriedades magnéticas, eletrônicas e ópticas, têm sido observadas em sistemas de nanopartículas (NPs) feitas de diferentes tipos de materiais. Em nanoestruturas do tipo núcleo@casca, a composição de um núcleo magnético com uma casca plasmônica apresenta características que lhe conferem promissor potencial para aplicações em áreas como eletrônica, biomédica, farmacêutica, óptica e catálise. Este trabalho apresenta uma nova abordagem para a produção de nanopartículas metálicas do tipo núcleo@casca pela combinação de técnicas físicas, o método de agregação gasosa e fontes de magnetron sputtering planar/radial. As NPs produzidas foram analisadas magneticamente por VSM e SQUID, sua morfologia por HRTEM, a sua composição por RBS e EDS, a sua estrutura cristalina por XRD e as propriedades ópticas por espectrofotometria de UV-Visível. Os resultados experimentais serão apresentados para o sistema Co@Cu, mas a técnica pode ser utilizada para produzir NPs compostas de outros elementos químicos. Em paralelo a produção de nanopartículas, o gerador de NPs foi totalmente reestruturado. Foram testadas diferentes aberturas de saída das nanopartículas, viabilizando uma deposição do material de forma homogênea em áreas maiores. As novas aberturas possuem formato cônico, plano e de grades (600 furos com diâmetros entre 50 µm e 224 µm). Através destas grades foi possível obter uma distribuição espacial homogênea de nanopartículas. A entrada de gás no gerador também foi modificada, a fim de otimizar a deposição dos aglomerados e obter uma reprodutibilidade na operação do equipamento. Foram testados diversos modos de entrada do gás: na lateral do copo, no centro em diferentes distâncias do alvo e por último na região em torno do alvo, sendo a última a melhor configuração obtida. / In recent years new magnetic, electronic and optical properties have been observed in nanoparticles (NPs) made of different conjugation of materials. In magnetic nanostructures of the core@shell type, the compound of a magnetic core and a plasmonic shell, provides many features with potential for applications in areas such as electronics, biomedical, pharmaceutical, optical and catalysis. This work presents a new approach to the production of metallic core@shell nanoparticles by the combination of physical techniques, the gas aggregation method and planar/radial magnetron sputtering sources. The produced NPs were magnetically analyzed by VSM e SQUID, the morphology by SEM and HRTEM, the stoichiometry by RBS and EDS, the crystal structure by XRD and UV-Visible spectrophotometry. The experimental results will be presented for the system Co@Cu but the technique can be used to produce NPs composed of other chemical elements. In parallel to the production of nanoparticles, the NPs generator has been completely redesigned. Different apertures were tested enabling deposition of homogeneous material in large areas. The nanoparticles are now spread on the substrate using the frontal apertures shaped as conical, plane and grids (600 holes ranging from 50 µm to 224 µm diameters). Through these grids we have obtained a homogeneous spatial distribution of NPs. The gas inlet in the NP generator was modified, in order to optimize the deposition of NPs and to obtain reproducibility in the operation of the equipment. Several gas injection modes were explored, as p.e. lateral; frontal to the center of the target at different distances; and finally through the gap of the sputtering gun, in parallel to the target surface. The last option was the best configuration.

The aim of this work is to prepare heterogeneous nanoparticles which means nanoparticles composed of more than one material. Our approach lies in in-flight modification of primary nanoparticles in the tubular sputtering system. Our tubular system contains copper target and we deposit copper onto the flying primary nanoparticles by magnetron sputtering. The main advantage of this approach is independence of fabrication of primary nanoparticles and their subsequent modification. At first we optimized fabrication of nanoparticles by the gas aggregation source on behalf of the next modification. We also characterized conditions in the tubular sputtering system. We found process in the tubular system to be very complex and sensitive to the changes of the operational parameters. There is a strong interaction between flying nanoparticles and the discharge in the tubular system. Due to this interaction the nanoparticles are trapped in the plasma and the deposition rate is pulsing. The result of this work is modification of nickel and silver nanoparticles, preparation of heterogeneous nanoparticles Ni/Cu and Ag/Cu. These heterogeneous nanoparticles vary in composition, shape and size according to the conditions in the tubular system. We also successfully prepared Janus nanoparticles which are interesting for their...

Dentre os principais avanços na área de ciência ou tecnologia dos materiais podemos ressaltar as atuais técnicas de produção, manipulação e análise de estruturas de tamanho muito reduzido, os quais possuem propriedades físicas (magnéticas, eletrônicas e óticas) diferentes das apresentadas pelos mesmos materiais em estruturas maiores. Nanopartículas (NPs) de metais nobres, principalmente ouro e prata, estão sendo utilizadas e incorporadas em diversas tecnologias que tiram proveito de suas características óticas ou condutivas Neste trabalho apresentamos uma metodologia de preparação de NPs de metais nobres, com a possibilidade de incorporá-las em um material dielétrico. As amostras, produzidas a partir da técnica de agregação gasosa, foram preparadas em um gerador de NPs, construído em um dos canhões de um sistema de magnetron sputtering comercial (AJA Internacional). No gerador, átomos são removidos do alvo e termalizados pelo fluxo do gás de trabalho, se condensando na forma de NPs. As NPs são extraídas do gerador aerodinamicamente e seguem em direção ao substrato. Utilizando um dos outros canhões do nosso sistema de sputtering podemos codepositar as NPs produzidas em uma matriz dielétrica ou metálica. Podemos também depositar camadas de filmes finos sobre o material produzido pelo gerador de NPs. As amostras de nanopartículas de ouro e prata produzidas foram caracterizadas a partir de técnicas de microscopia eletrônica de varredura (MEV), retroespalhamento Rutheford (RBS), espectrofotometria de UV-Visível e microscopia ótica em campo próximo (SNOM). A partir das imagens de MEV, podemos inferir a presença da matriz dielétrica a partir da separação das NPs e essa presença pode ser confirmada pela análise dos resultados de RBS. Por fim a análise do espectro de absorbância das amostras em conjunto com as imagens de SNOM demonstrou o comportamento plasmônico das amostras produzidas, sobretudo das NPs codepositadas em matriz dielétrica. / In the midst of main advances in material science and technology we can highlight the new techniques of preparation, manipulation and analyses of structures of very small size. They have physical properties (magnetic, electronic and optical) different from those presented by the same material, but in bigger dimension. Noble metal nanoparticles, mainly gold and silver, are incorporated into various technologies in order to take advantage of their optical or electric properties. In this work, we present a technique to produce noble metal nanoparticles by a physical method that also permits to imbed them in a dielectric material matrix. The samples, produced using the gas aggregation technique, were prepared in a nanoparticle gun, developed on one of the guns of a commercial magnetron sputtering system (AJA International). In the nanoparticles generator, atoms are removed from the target and thermalized by the flow of the sputtering working gas, and they are also condensed to form the nanoparticles. The nanoparticles are extracted from the generator aerodynamically and then they proceed to the substrate. Using another gun of the sputtering system we can deposit the nanoparticles produced in a dielectric or metallic matrix. We can also deposit under and capping layers of thin films on the nanoparticles layer produced. The samples of gold and silver nanoparticles produced were characterized by scanning electron microscopy (SEM), Rutherford backscattering analysis (RBS), UV-Visible spectrophotometry and near field optical microscopy (SNOM). In the SEM images, from the distribution and morphology of the nanoparticles it was possible infer the presence of the dielectric matrix, and this was also confirmed by the RBS measurements. Finally, absorbance spectrum of the samples together with the SNOM images have demonstrated the plasmonic character of the samples produced, specially for the NPs co-deposited in the dielectric matrix.

Title: In-flight modification of nanoparticles by chemically active plasma Author: Hana Libenská Department: Department of Macromolecular Physics Supervisor: Mgr. Jan Hanuš Ph.D., Department of Macromolecular Physics Abstract: This diploma thesis is focused on a fabrication of the iron nanoparticles using the gas aggregation source with a planar magnetron and their in flight modification by chemically active plasma. The modification of the nanoparticles is based on a radiofrequency glow discharge, that takes place right after the nanoparticles flew out of the gas aggregation source. Nanoparticles are prepared in an argon atmosphere in which a small amount of the n-hexane has been admixed. This n-hexane impurity caused an increase in a deposition rate and higher time stability. The modification takes place in a glow discharge containing a pure argon, or in the mixtures of argon with n-hexane, ethylendiamine, hydrogen or nitrogen. Prepared nanoparticles were characterized using the X-ray photoelectron spectroscopy, scanning and transmission electron microscopy, X-ray diffraction and other techniques. The main aim of this work was to study the influence of the additional discharge on the iron nanoparticles. The chemical composition of the nanoparticles was measured immediatelly after their deposition without...

Title: Structuring of plasma polymers: new methods for fabrication of nano-architectured thin films Author: Daniil Nikitin Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, PhD, Department of Macromolecular Physics/Charles University Abstract: The PhD thesis aims at the investigation of nanostructures based on plasma polymers. The main attention is paid to the combination of a gas aggregation cluster source with plasma-assisted vapor phase deposition for the fabrication of metal-polymer nanocomposites with bactericidal potential. Copper nanoparticles were incorporated into a biocompatible matrix of plasma polymerized poly(ethylene oxide) (ppPEO). The efficiency of such nanocomposite against multi-drug resistant bacteria was demonstrated. It was found that the segmental dynamics of the plasma polymer significantly changed in the presence of nanoparticles as revealed by the measurements of the dynamic glass transition temperature. The nanoscale confinement crucially influences the non-fouling properties of poly(ethylene oxide). A separate chapter is dedicated to the examination of the nanoparticle formation, growth and transport inside the source. Copper and silver nanoparticles were detected in situ in the gas phase...

Title: Structuring of plasma polymers: new methods for fabrication of nano-architectured thin films Author: Daniil Nikitin Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Doc. Ing. Andrey Shukurov, PhD, Department of Macromolecular Physics/Charles University Abstract: The PhD thesis aims at the investigation of nanostructures based on plasma polymers. The main attention is paid to the combination of a gas aggregation cluster source with plasma-assisted vapor phase deposition for the fabrication of metal-polymer nanocomposites with bactericidal potential. Copper nanoparticles were incorporated into a biocompatible matrix of plasma polymerized poly(ethylene oxide) (ppPEO). The efficiency of such nanocomposite against multi-drug resistant bacteria was demonstrated. It was found that the segmental dynamics of the plasma polymer significantly changed in the presence of nanoparticles as revealed by the measurements of the dynamic glass transition temperature. The nanoscale confinement crucially influences the non-fouling properties of poly(ethylene oxide). A separate chapter is dedicated to the examination of the nanoparticle formation, growth and transport inside the source. Copper and silver nanoparticles were detected in situ in the gas phase...

Smooth fluorocarbon plasma polymer films have been for a long time considered for fabrication of hydrophobic and slippery coatings. Interest in fluorocarbon materials was also supported by their excellent self-lubricant, dielectric properties and chemical inertness. This thesis is focused on development of new methods for fabrication of fluorocarbon plasma polymes, which could combine the chemical composition and the physical structure necessary for reaching superhydrophobic character of coatings. Poly(tetrafluoroethylene) was the subject material. RF magnetron sputtering using gas aggregation cluster source was the method adapted to fabricate fluorocarbon nanostructured films with chemical composition close to conventional bulk PTFE, but with high degree of cross- linking and branched structure. A model of growth of such plasma polymer nanostructures was discussed.

Title: Multicomponent plasma polymers with spatially controlled properties Author: MSc. Pavel Pleskunov Department / Institute: Department of Macromolecular Physics/Charles University Supervisor of the doctoral thesis: Prof. Ing. Andrey Shukurov, PhD, Department of Macromolecular Physics / Charles University Abstract: Mixing of two (or more) polymers often leads to phase separation and to the formation of nanoscale architecture, which can be highly attractive in various applications including controllable drug delivery, fabrication of separation and solid electrolyte membranes, gas storage, etc. Different wet-chemistry techniques already exist to produce nanophase-separated polymers; however, capturing the resultant polymeric structure in a predictable manner remains a challenging task. In this thesis, a low-temperature plasma-based strategy is investigated for the production of multicomponent thin films of plasma polymers with spatially discriminated nanoscale domains. Gas aggregation cluster source is used for the fabrication of nanoparticles of plasma polymerized acrylic acid, whereas Plasma-Assisted Vapor Phase Deposition is used for the deposition of thin films of poly(ethylene oxide) plasma polymer. Embedding of nanoparticles into matrices of thermodynamically incompatible plasma polymer as well as...