Dissertations / Theses on the topic 'Composite metal nanoparticles'

Les catalyseurs à base de zéolite ont été largement utilisés dans la conversion de la biomasse. Les rendements catalytiques des produits recherchés sont fortement limités en raison de la taille relativement petite des pores dans les zéolithes et la préparation du catalyseur par imprégnation conduit généralement à des nanoparticules métalliques relativement grosses et à un faible contact entre les sites métalliques et acides. Le but de ce travail est la conception de catalyseurs nanocomposites métal-zéolithe contenant des nanoparticules de ruthénium uniformément réparties dans les zéolithes hiérarchiques BEA et ZSM-5. L'utilisation de ruthénium évite la formation de silicates et d'aluminates métalliques inertes difficilement réductibles, tandis que les nanotubes de carbone avec des nanoparticules d'oxyde métallique supportées jouent un rôle de gabarit sacrificiel, ce qui permet de créer une mésoporosité et d'apporter une fonctionnalité métallique à l'intérieur de la matrice zéolithique. Par rapport aux catalyseurs métalliques supportés par des zéolites classiques, les zéolites ruthénium hiérarchiques synthétisées présentaient une activité beaucoup plus élevée et une sélectivité en méthane plus faible dans la synthèse Fischer-Tropsch. La caractérisation des catalyseurs préparés a indiqué l'initiation de la cristallisation des zéolites sur des nanoparticules métalliques. Cet effet a en outre été utilisé pour augmenter la dispersion de nanoparticules métalliques par cristallisation secondaire de Ru supporté sur ZSM-5. Nos résultats montrent une redispersion significative des nanoparticules d'oxyde métallique incorporées et une augmentation de l'activité des réactions modèles. De plus, une stratégie de synthèse a été développée pour la préparation de catalyseurs nanocomposites métalliques et zéolithiques hiérarchiques pour la synthèse directe d'iso-paraffines à partir de gaz de synthèse. Les nanocomposites sont synthétisés en trois étapes. Dans la première étape, la zéolite mère (noyau) est gravée avec une solution de fluorure d'ammonium. La gravure crée de petits mésopores à l'intérieur des cristaux de zéolite. Dans la deuxième étape, les nanoparticules de Ru préparées à l'aide de microémulsion eau-dans-huile sont déposées dans les mésopores de la zéolithe. Dans la troisième étape, une enveloppe de zéolite de zéolites de type MFI (silicalite-1 ou ZSM-5) est cultivée sur les cristaux de zéolite parent recouvrant à la fois la surface gravée et les nanoparticules métalliques. Ainsi, les nanoparticules métalliques deviennent entièrement encapsulées à l'intérieur de la matrice zéolithique. Les paramètres les plus importants tels que la teneur en ruthénium, la mésoporosité de la zéolite, et plus particulièrement, l'acidité de l'enveloppe du catalyseur, qui affectent les performances catalytiques des matériaux nanocomposites synthétisés dans la synthèse Fischer-Tropsch à basse température ont été identifiés dans ce travail. La quantité relative plus élevée d'iso-paraffines a été observée sur les catalyseurs contenant une enveloppe de ZSM-5. La proximité entre les sites métalliques et acides dans l'enveloppe zéolithique des catalyseurs nanocomposites est un paramètre crucial pour la conception de catalyseurs bifonctionnels zéolithiques métalliques efficaces pour la synthèse sélective de carburants de type essence via la synthèse Fischer-Tropsch, tandis que l'acidité du cœur du catalyseur a qu'un impact limité sur les performances catalytiques
Zeolite-based catalysts have been widely used in the conversion of biomass. The catalytic yields of the desired products are strongly limited due to the relatively small size of the pores in zeolites and the catalyst preparation by impregnation usually leads to relatively large metal nanoparticles and low contact between metal and acid sites. The purpose of this work is the design of metal-zeolite nanocomposite catalysts containing ruthenium nanoparticles uniformly distributed in the hierarchical BEA and ZSM-5 zeolites. Use of ruthenium avoids formation of inert hardly reducible inert metal silicates and metal aluminates, while carbon nanotubes with supported metal oxide nanoparticles play a role of sacrificial template, which allows creating mesoporosity and bringing metallic functionality inside the zeolite matrix. Compared to the conventional zeolite supported metal catalysts the synthesized hierarchical ruthenium-zeolites exhibited much higher activity and lower methane selectivity in Fischer-Tropsch synthesis. Characterization of the prepared catalysts has indicated initiation of crystallization of zeolites over metal nanoparticles. This effect has been further used to increase the dispersion of metal nanoparticles by secondary crystallization of Ru supported over ZSM-5. Our results show significant re-dispersion of embedded metal oxide nanoparticles and increase in the activity of model reactions. In addition, a synthetic strategy was developed for the preparation of hierarchical metal and zeolite nanocomposite catalysts for direct synthesis of iso-paraffins from syngas. The nanocomposites are synthesized in three steps. In the first step, the parent (core) zeolite is etched with an ammonium fluoride solution. The etching creates small mesopores inside the zeolite crystals. In the second step, the Ru nanoparticles prepared using water-in-oil microemulsion are deposited in the mesopores of the zeolite. In the third step, a zeolite shell of MFI-type zeolites (silicalite-1 or ZSM-5) is grown on the parent zeolite crystals coating both the etched surface and metallic nanoparticles. Thus, the metal nanoparticles become entirely encapsulated inside the zeolite matrix. Most important parameters such as ruthenium content, zeolite mesoporosity, and more particularly, the acidity of the catalyst shell, which affect the catalytic performance of the synthesized nanocomposite materials in low-temperature Fischer−Tropsch synthesis were identified in this work. The higher relative amount of iso-paraffins was observed on the catalysts containing a shell of ZSM-5. The proximity between metal and acid sites in the zeolite shell of the nanocomposite catalysts is a crucial parameter for the design of efficient metal zeolite bifunctional catalysts for selective synthesis of gasoline-type fuels via Fischer−Tropsch synthesis, while the acidity of the catalyst core has only a limited impact on the catalytic performance

It is ideal to theoretically predict the activity of a catalyst. It has been recognized that not only the type of metal, but also its atomic size plays an important role in catalysis. In the past, atomic clusters have been created by sputtering from a sacrificial metal plate and then using a mass selector to choose cluster sizes from 1-233 atoms of gold. This approach has practical limitations. In this thesis, I describe a procedure by which atomic clusters of gold containing 1-8 atoms are deposited in polyaniline as an isolation matrix. My atomic deposition follows a cyclic pathway. Atomic clusters of palladium and atomic alloys of gold and palladium are also deposited in polyaniline using the same process. It is to show that this method will also work for other metals. These composite materials are characterized, and the catalytic activity for alcohol oxidation is evaluated. This thesis is divided into seven chapters. The first chapter discusses the chemistry of polyaniline for using gold and palladium as catalysts. The technique developed to deposit the atomic clusters is discussed in the second chapter. This technique deposits one atom of metal per imine site on polyaniline, per cycle. The cycle is repeated n-times until a cluster of specified size, Mn, and composition has been synthesized. It is known that polyaniline plays an important role in stabilization of the formed clusters which prevents their aggregation. The optimization of this technique is the topic of the third chapter along with the description of how these composite films are produced. To end this chapter, the composite films are characterized by cyclic voltammetry, Kelvin probe, and X-ray photoelectron spectroscopy. In chapters 4 and 5, the catalytic activity of the polyaniline/gold composites for the oxidation of alcohols in alkaline media using cyclic voltammetry is evaluated. In chapter 4, the correlation of the electrochemical activity for the oxidation of n-PrOH with the odd-even pattern from the calculated HOMO-LUMO gap energies for the same size clusters is shown. It is shown that the infrared spectrum of polyaniline with different sizes of atomic gold clusters also follows the odd-even pattern. Chapter 5 expands on the discussion of the catalytic oxidation of alcohols. The oxidation of methanol, ethanol, propanol, and butanol is surveyed. The peak currents are again dominated by the odd-even pattern. In chapter 6, the versatility of the atomic deposition cycle is shown by depositing atomic palladium clusters. The peak currents for the oxidation of n-PrOH by these palladium composite films again follows the predicted pattern of the calculated HOMO-LUMO gap energies for atomic palladium clusters. This chapter also explores bimetallic atomic clusters of gold and palladium. The results indicate that the catalytic activity depends on the orientation of the cluster in the polyaniline matrix. Chapter 7 discusses the oxidation of methanol, ethanol, and isopropanol on AunPd1 bimetallic atomic clusters. The addition of palladium in the cluster increases the peak current densities for the oxidation of both alcohols except for the most stable of the atomic gold clusters, while it inactivated the electrodes for isopropanol. The possible future work for this project is discussed in chapter 8. Overall, this thesis has developed a novel and unique technique for depositing atomic metal clusters into a polyaniline matrix. The technique is versatile enough to deposit atomic metal clusters other than gold, as shown by creating atomic palladium clusters and atomic bimetallic clusters of gold and palladium. This is extremely useful, since this single technique can produce many different types of atomic catalysts. The composite materials have been shown to be catalytically active for the oxidation of alcohols in alkaline media. This indicates a significant improvement to conserve precious metals while still retaining a high catalytic activity.

Metal-Organic Frameworks (MOFs) sont constitués de clusters métalliques connectés dans les ligands organiques. L'objectif principal de ma thèse était de caractériser la texture, la structure et la réactivité des MOFs dans le cas de systèmes présentant des défauts, amorphes et composites.La première étude est centrée sur les propriétés de la famille Fe-BTC et ce travail a été réalisé en collaboration avec l'Université d'Utrecht et l'Université d'Oxford. Une étude comparative entre le MIL-100(Fe) et son homologue commercial Basolite F300 (BASF) qui est amorphe ont été évaluées par l’adsorption de méthanol et d'autres techniques de caractérisation. De plus, les deux matériaux ont été testés pour être utilisés comme support pour l'imprégnation des métaux.Dans la deuxième étude, le broyage à la bille est utilisé comme stratégie de modification post-synthèse de MOFs. Le matériau ZIF-8 a été sélectionné de cas car il s'agit d'un MOF disponible dans le commerce (Basolite Z1200) et qui est en train de devenir de référence dans ce domaine. Ce chapitre examiner des propriétés flexibles, de la texture, de la structure, et la réactivité.Les MOFs UiO-66 et MOF-808 sont également analysées. Ces études ont été réalisées en collaboration avec l'Université Technique de Munich. UiO-66 contenant différents défauts d'ingénierie sont examinées. Nous avons démontré que les mesures d’adsorption de vapeur peuvent être un outil précieux pour accéder à la chimie des défauts. Le deuxième système est la série MOF-808 qu’une étude complète est présentée allant des diverses stratégies de synthèse de MOFs défectueux et composites jusqu'à leur propriété d'adsorption et de réactivité
Metal-organic frameworks (MOFs) are a class of porous materials that constructed from metal clusters connected with organic linkers. The main objective of my PhD was to characterize the texture, structure, and reactivity of MOFs materials with a particular focus on defective, amorphous and composite materials. The first study is centered on the properties of the Fe-BTC family and this work was realized in collaboration with Utrecht University and the University of Oxford. A comparative study between crystalline MIL-100(Fe) and its commercial counterpart amorphous Basolite F300 (BASF) were studied by using methanol adsorption to predict the reactivity. Other characterization methods are introduced to investigate both materials which were further tested to be used as supports for metal-impregnation. In the next study, ball-milling was employed as a post-synthesis strategy for MOF modification. This ZIF-8 material was selected since it is commercially available (Basolite Z1200) and is becoming one of the reference materials in this area. Extensive studies including flexibility, textural, structural, as well as reactivity of different milling products is presented. Zirconium-based MOFs (UiO-66 and MOF-808) were also examined in this thesis. These studies were performed in collaboration with TU Munich. UiO-66 series containing engineered defects are first examined. We demonstrated that vapor adsorption measurement is a valuable tool to access the chemistry of the defects. The second studied system is MOF-808 series, where a comprehensive study is presented starting from synthesis strategies of defective and composite MOFs up to adsorption properties and reactivity

En raison de leur propriétés spécifiques élevées, par rapports aux alliages légers, les Composites à matrice métallique (CMM) représentent des matériaux d'intérêt pour des applications de haute technologie dans les domaines aéronautique et aérospatiale. Les CMM les plus couramment utilisés sont à renfort particulaire, ou PRMMC, et à matrice Al en raison de leur faible densité. Cette thèse porte sur la mise au point de PRMMC à renfort nanométrique par une voie de synthèse réactive globale. En raison des normes encadrant l’usage des nanomatériaux et visant à limiter l’exposition des usagers et de l’environnement, la manipulation de poudres de taille nanométrique est coûteuse et problématique dans le cadre d’un usage industriel. La nouvelle voie de synthèse qui a été développée dans le cadre de cette thèse a permis de démontrer la faisabilité de composites à matrice métallique et à renfort particulaire nanométrique, dimension moyenne de 30 nm, sans avoir recourt initialement à des poudres de taille nanométrique. Le procédé étudié consiste en une réaction chimique à haute température entre deux matériaux précurseurs qui conduit à la formation in-situ non seulement du renfort mais aussi de la matrice. Par rapport aux techniques de synthèse classiques, cette technique permet de synthétiser des nanoparticules in situ et d’en contrôler la taille. De plus, la matrice et le renfort étant co produits par la réaction à haute température, l’interface entre les deux phases est exempte de couches d’oxydes, ce qui lui assure une très bonne adhésion. Dans le cadre du projet ANR NanoTiCAl, la faisabilité de cette nouvelle méthode a été étudiée à travers le cas d'un composite à matrice aluminium renforcé par des particules de carbure de titane (TiC). Les synthèses ont été réalisées entre 900°C et 1000°C à partir d’un couple de précurseurs incluant le graphite et un aluminiure de titane (Al3Ti). Le composite obtenu, caractérisé par un taux de renfort élevé de 34wt.%, possède un module de Young de 106 GPa, un allongement maximal à la rupture de 6% ainsi qu’une énergie à rupture de l’ordre de 28 J.cm-3. Ces valeurs démontrent un compromis entre résistance et capacité d’endommagement original et particulièrement intéressant, jamais observé dans la littérature pour des composites d’une teneur en renfort aussi importante. La caractérisation fine de la microstructure du composite ainsi que du renfort TiC après extraction du composite massif, ont permis de mieux comprendre les mécanismes à l’oeuvre dans cette voie de synthèse réactive. Enfin, sur la base de la compréhension obtenue dans le cas du composite Al/TiC, des critères ont été identifiés permettant d’aller vers une généralisation de ce procédé de synthèse. La pertinence de cette généralisation a finalement pu être démontrée par quelques mises en application à d’autres systèmes
Metal Matrix Composites (MMCs) have attracted research and industrial attentions as materials for high technological applications in the aeronautic and aerospace industry. The MMCs differ by their high specific mechanical properties compared to light weight alloys. The most commonly used are the Particulate Reinforcement Metal Matrix Composites (PRMMCs), especially the Al based matrices because of their low density.This thesis deals with the reactive synthesis of PRMMCs reinforced by nanoparticles. Because of the standards governing the use of nanomaterials to limit the exposure of users and environment, handling nanoscaled powders is very problematic and expensive in industry. Furthermore, the cost of this kind of processes is very high. This new synthesis route, developed during this thesis, shows the feasibility of PRMMCs reinforced by nanosized particles, with a mean size of 30 nm, without using any starting nanoparticles.The process consists in a chemical reaction at high temperature between precursor materials which leads to form both of the matrix and the reinforcement phase. Compared to conventional synthesis techniques as stir casting, this route allows to synthesis nanoparticles in-situ and to control their size. In addition, the matrix and the reinforcement, which are formed by a reaction at high temperature, have an interface free of oxide layers which assures a good adhesion.In the NanoTiCAl project, the feasibility of this new method is illustrated in the case of an aluminium based composite reinforced by titanium carbide (TiC). The synthesis were realized between 900°C and 1000°C from a couple of precursors including graphite and titanium aluminide (Al3Ti). The resulting composite, characterized by a high reinforcement ratio (34 wt.%), presents a Young’s modulus of 106 GPa, a maximum elongation of 6 % and a high toughness, about 28 J.cm-3. These values represent an uncommon compromise between strength and toughness never seen in the literature regarding to the high content of reinforcement.The characterization of the composite microstructure and of the reinforcement phase, after extraction of the solid composite, allowed a better understanding of the reaction mechanism during the reactive synthesis. Finally, based on our understanding of the Al-TiC composite, criteria have been identified to generalize this synthesis process. This generalization was demonstrated with success in other systems

This thesis investigates the nonlinear optical properties of ZnO and ZnO-Au composite nanostructures. For applications such as photodynamic therapy, it is desirable to use nanoparticles to generate localised UV emission while illuminating them with visible or infrared light. This is possible using nonlinear optical processes such as two photon absorption. Nonlinear optical processes however, are extremely weak, so this work investigates the potential of increasing the efficiency of two photon absorption in ZnO nanoparticles by coupling them to metal nanoparticles. Using new experimental methods, the two photon absorption and resulting UV emission from the nanoparticles are measured.

L’influence des renforts nanoparticules de TiB2 (6 wt.%) sur la précipitation interfaciale de la phase (Zn1.5Cu0.5)Mg, la résistance à la traction et la fissuration sous chargement de fatigue (fatigue crack growth-FCG) des composites à matrice de Al-Zn-Mg-Cu ont été étudiées. Des échantillons de composites ont été obtenus par réaction in-situ pendant le moulage suivi d’un FSP (friction stir processing) et une extrusion à chaud. Seuls les échantillons moulés et extrudés ont été utilisés pour étude de FCG à cause de la limitation de la taille après FSP. Des observations au microscope électronique à balayage (SEM), avec la diffraction des électrons rétrodiffusés (SEM/EBSD) et au microscope électronique en transmission à haute résolution (HRSTEM) ont été réalisées pour caractériser la microstructure.Des échantillons présentent une structure des grains équi-axiaux et des nanoparticules de TiB2 sont distribuées de façon homogène dans la matrice. En état de solution solide, l’interface TiB2/Al est de nature semi-cohérente et très propre. En état de vieillissementou ou sur vieillissement, la précipitation interfacaile hétérogène de la phase (Zn1.5Cu0.5)Mg a été observée. La cinétique de la précipitation interfaciale a été discutée. Les interfaces entre Al/(Zn1.5Cu0.5)Mg/TiB2 sont quasi cohérentes et l’interface TiB2/Al a été renforcée grâce à la réduction de l’énergie de l’interface. Ce mécanisme de précipitation interfaciale peut expliquer l’effet de renforcement de l’interface contribuant simultanement l’augmentation de la résistance et de l’élongation des échatillons de composite.La majorité de nanoparticules TiB2 tentent de s’agglomérer le long des joints de grains dans des échantillons sans FSP. La vitesse de croissance de fissure a été augmentée à l’intérieur des grains avec un facteur d’intensité (ΔK) intermédiaire ou important à cause de l’affinement de grains. Cependant, la vitesse de croissance de fissure a été diminuée aux joints de grains avec (ΔK) faible ou intermédiaire à cause de la présence des clusters de TiB2 tandis que cette vitesse augmente avec (ΔK) important à cause de la coalescence des micropores
The influences of TiB2 reinforcement nanoparticles (6 wt.%) on the interfacial precipitation of (Zn1.5Cu0.5)Mg phase, the associated tensile and fatigue crack growth (FCG) properties of the Al-Zn-Mg-Cu matrix composites have been studied. The composite samples were produced by in-situ reaction during casting followed by friction stir processing (FSP) and hot extrusion, while only casted and extruded samples were used for evaluating FCG due to size limit of the nugget zone after FSP. Scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and high-resolution scanning transmission electron microscopy (HRSTEM) were employed for the microstructure characterization.The as-processed composite samples contain the fine equiaxed-grain structure, where TiB2 nanoparticles are homogenously distributed. At solid-solution state, the TiB2/Al interfaces are featured by the clean and semi-coherent nature. At the peak-aged and overaged states, the interface precipitate determined as (Zn1.5Cu0.5)Mg phase was formed, and the underlying heterogeneous interfacial precipitation kinetics was discussed. The Al/(Zn1.5Cu0.5)Mg/TiB2 multi-interfaces were revealed to be almost coherent, and the TiB2/Al interfaces were thus strengthened due to the greatly reduced coherency strains. This mechanism was proposed as precipitation assisted interface strengthening, which has contributed to the simultaneously enhanced tensile strength and uniform elongation of the as-processed composite.The majority of TiB2 nanoparticles tend to aggregate along grain boundaries (GBs) in the composite samples without FSP. The FCG rate is increased inside grains at intermediate and high stress intensity factor (ΔK) ranges due to the refined grain size. However, the FCG rate at the GBs is decreased at the low and intermediate ΔK ranges by fatigue crack deflection and trapping due to the presence of TiB2 clusters, while it increases at the high ΔK range due to microvoid coalescence

The research presented in this dissertation pioneers a new area of study in CB[n]-metal nanoparticle (CB[n]-NP) supramolecular assemblies. While many of the supramolecular motifs are only functional in organic media, cucurbit[n]urils (CB[n]s), as a result of their water solubility and unique multi-functional macrocyclic structure, are promising as a series of robust supramolecular building blocks for both self-assembly of the CB[n]-NP organic-inorganic composite frameworks and the subsequent molecular recognition of small organic molecules in aqueous media. While various ways in integrating CB[n]s with metal nanoparticles have been investigated, two major systems are presented here, namely, portal binding (Type III) and indirect binding (Type IV) composites. Chapter 1 introduces metal nanoparticles based on their unique properties and the corresponding applications in photonics, catalysis and as nano-scaffolds. After a brief description of various supramolecular motifs, macrocyclic molecules will be highlighted as a series of robust supramolecular building blocks. Motivations and challenges in incorporating supramolecular self-assembling and molecular-recognition motifs into nanomaterials are then discussed and illustrated by specific examples in the literature. Precedent examples of composites between macrocyclic molecules and metal nanoparticles are critically reviewed in the latter part of the chapter. Chapter 2 describes the synthesis and characterisation of aqueous metastable gold nanoparticles (AuNPs*), which were discovered to be a facile intermediate in the fabrication of CB[n]-AuNPs. Although similar syntheses have been reported, there is no report on investigating the “metastability” of these AuNPs* or optimising different parameters for practical uses. In the absence of any additional stabilising ligands, AuNPs* are only stabilised by a layer of adsorbed chloride ions, which can then be easily displaced by a wide variety of water-soluble ligands, including weakly bound CB[n]s. This serves as an important foundation for the subsequent research in Type III CB[n]-AuNP systems which will be discussed in detail in the next two chapters. Chapter 3 focuses on the synthesis and characterisation of Type III CB[n]-AuNP supramolecular composites, in which the CB[n] molecules are dynamically capped by AuNPs on either or both of their portals. The CB[n]-AuNPs can then further self-assemble and form well-defined dynamic aggregates in aqueous media, with a controllable ratio between singly and doubly capped CB[n]s. The first report of Type III CB[n]-AuNP in the literature is presented here, contributing to the early development of this field of study which is now being pursued together with a number of research groups around the world. Owing to the high rigidity and well-defined molecular geometry of such molecules, CB[n]s can act as a precise sub-nanometer junction between plasmonically active AuNPs within the dynamic composites. Chapter 4 focuses on discussing the plasmonic properties of these Type III CB[n]-AuNP systems, and their applications in surface-enhanced Raman scattering (SERS) spectroscopy. Through the aid of computational simulation, we are able to assign each major peak in the Raman and SERS spectra, as well as understand their systematic shifts across the CB[n] homologues. Armed with such fundamental knowledge, we then further employ the SERS-technique to study the aggregation kinetics and the corresponding evolution of plasmonic behaviours of the Type III CB[n]-AuNP systems. The precise and well-defined plasmonic junctions, created by doubly AuNP-capped CB[n]s, allow aggregation kinetics to be studied in the finest details, which is unprecedented in any previous reports. Furthermore, hydrophobic cavity of the CB[n] hosts offers the possibility for small organic guest molecules to be encapsulated right at the heart of these plasmonic hot spots, leading to a self-calibrated molecular-recognition-based in situ SERS sensing system. An initial example of this powerful sensing system is presented at the end of the chapter. Chapter 5 highlights an alternative promising strategy in building up dynamic hierarchical materials in different solvents. The first part of this chapter describes a novel method of dispersing AuNPs within a polymer matrix. Thiol-terminated ureido-pyrimidinone (UPy)-functionalised polymers are attached to AuNPs, creating a polymeric shell with quadruple hydrogen-bonding units on the periphery. The second part of the chapter focuses on Type IV CB[8]-NP supramolecular composites, in which CB[8] and metal nanoparticles are indirectly tethered via host-guest complexation with guests that are covalently anchored on the surface of nanoparticles. While CB[8], a larger homologue in the CB[n] family, can simultaneously accommodate two complementary guests in its cavity, it can act as a robust and versatile “supramolecular handcuff” that ligates appropriately functionalised molecules and nano-objects together in a reversible manner. Dynamic hierarchical composites based on self-assembly between guest-functionalised AuNPs and a water-soluble polymer with pendant complementary guests is presented.

Die Entwicklung neuartiger transparenter Materialien durch Kombination von organischen Polymeren und anorganischen Füllstoffen wurde untersucht. Für die Synthese der nanoskopischen anorganischen Füllstoffe wurde der Sol-Gel-Prozess für Metallfluoride mit Magnesium angewandt und auf Zirkonium und Titan erweitert. Auch wurden neue Herstellungs- und Trocknungsmethoden für die daraus gewonnenen Xerogele variiert und optimiert. Die Charakterisierung der hergestellten Metallfluorid-Sole und daraus gewonnener Nanopartikel erfolgte mittels NMR- und IR-Spektroskopie sowie SAXS- und TEM-Messungen und Elementaranalysen. Zur homogenen Mischbarkeit von anorganischen Füllstoffen und organischer Polymermatrix sind Modifikationen der Partikeloberfläche notwendig. Diese erfolgten über kovalent gebundene, teilweise perfluorierte, Carbonsäuren. Der Fortschritt der Modifizierung sowie die Eigenschaften der erhaltenen modifizierten Nanopartikel wurden mittels NMR- und IR Spektroskopie, teilweise auch mittels TA, untersucht. Unter Verwendung verschiedener transparenter und industriell relevanter Polymermatrices konnten durch homogene Verteilung der Nanopartikel transparente Kompositmaterialien erhalten werden. Die Veränderung der mechanischen und thermischen Eigenschaften der einzelnen neuen Materialien im Vergleich zu den reinen Polymeren wurde mittels DSC, Zugversuchen und Nanoindentation bestimmt. Zusätzlich zu diesen Anwendungsbereichen wurde der Einsatz der Nanopartikel in Elektrodenmaterialien zur Steigerung der Lebensdauer von Akkumulatoren und daraus resultierender Leistungsverbesserung untersucht.
The development of new transparent materials by combination of organic polymers and inorganic fillers was investigated. The fluorolytic sol-gel process was used to prepare fluorine containing nanoscopic inorganic fillers with magnesium, zirconium and titanium as metal components. The preparation and drying methods for the synthesis of xerogels was varied and optimized. Characterization of the metal fluoride sols and the nanoparticles obtained from the sols was executed by NMR and IR spectroscopy as well as SAXS and TEM measurements and elemental analysis. To achieve homogeneous miscibility for the inorganic fillers with the organic polymer matrix modification of the particles’ surface is crucial. This was achieved by covalent attachment of carbon acids; in case of fluorine polymers perfluorinated carbon acids were used. The progress of surface modification and the properties of the modified nanoparticles were monitored by NMR and IR spectroscopy. Based on thermal analysis, thermal stability of the modified nanoparticles was investigated. The modified metal fluoride nanoparticles were introduced into transparent and for industrial applications relevant polymer matrices. A homogeneous distribution to transparent nano composite materials was observed. The alteration of mechanical and thermal properties of the new materials was investigated by DSC, tension tests and nanoindentation and compared with the unmodified pure polymers. Another field of application of these nanoparticles is their application on electrode materials with the aim to improve electrode lifetime and to achieve a better performance of rechargeable batteries.

With all the improvements in cancer treatments, multidrug resistance is still the major challenge in treating cancer. Cells can develop multidrug resistance (MDR) during or after treatment, which will render the cancer cells resistant not only to the chemotherapy drug being used but also to many other structurally- and mechanically-different chemotherapeutics. In the first project, the main focus was on development of drug resistant cell lines by selection with taxol. Gene changes in the L1T2 cell line after treatment with Taxol was studied. Treatment of L1T2 cells with taxol leads to changes in the expression of ABC transporter proteins, whereas the combination of Taxol with protease inhibitors leads to increased efficacy via inhibition of P-glycoprotein (P-gp). In the second project, we showed that our innovatively-designed Au-loaded poly(lactide-co-glycolic acid) nanoparticles (GPLGA NPs) are able to cross biological barriers and deliver inside the cells without being recognized by the ABC protein transporter. (We focus specifically on P-gp-mediated drug efflux in a model of HEK cell lines.) The concentration of gold was measured using inductively-coupled plasma/mass spectrometry (ICP-MS) after 6- and 24-hour treatment of GPLGA NPs, which did not show significant increase of gold inside the cells in presence of the P-gp inhibitor valspodar. Cancer cells were treated with the GPLGA NPs for 24 hours and then irradiated 5 minutes at 1Wcm-2 using laser settings at 680 or 808 nm. Heat generation in cancer cells, after internalizing GPLGA NPs and laser irradiation, was significant irrespective of laser wavelength. The plasmomic heating response in this in vitro model can be a step closer to overcome MDR. Finally, for the third and last project represented in this dissertation, the focus was on the design and synthesis of innovative, biodegradable PLGA NPs, encapsulated with the platinum(II)-based non-organometallic/non-cyclometalated phosphorescent complex PTA = [Pt(ptp)2], a brightly phosphorescent complex (ptp = square-planar bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]). Size-tunable, emission-polarized phosphorescent PTA-loaded PLGA NPs were synthesized using a single-emulsion, solvent evaporation technique. Photoluminescence characterization shows that PTA-loaded PLGA NPs exhibit strong and stable orange emission with peak maximum ~ 580 nm. The photoluminescence quantum yield (QY) of the synthesized PTA-PLGA NPs was evaluated at ~55%, which allows recording of images with a much better contrast than that with PTA in organic solvents without the PLGA (QY ~0.5% and ~0 emission polarization) or even that with typical fluorescent organic dyes like rhodamines.

Cellulose is the most abundant biopolymer on earth. In this work it has been used, in various forms ranging from wood to fully processed laboratory grade microcrystalline cellulose, to synthesise a variety of metal and metal carbide nanoparticles and to establish structuring and patterning methodologies that produce highly functional nano-hybrids. To achieve this, the mechanisms governing the catalytic processes that bring about graphitised carbons in the presence of iron have been investigated. It was found that, when infusing cellulose with an aqueous iron salt solution and heating this mixture under inert atmosphere to 640 °C and above, a liquid eutectic mixture of iron and carbon with an atom ratio of approximately 1:1 forms. The eutectic droplets were monitored with in-situ TEM at the reaction temperature where they could be seen dissolving amorphous carbon and leaving behind a trail of graphitised carbon sheets and subsequently iron carbide nanoparticles. These transformations turned ordinary cellulose into a conductive and porous matrix that is well suited for catalytic applications. Despite these significant changes on the nanometre scale the shape of the matrix as a whole was retained with remarkable precision. This was exemplified by folding a sheet of cellulose paper into origami cranes and converting them via the temperature treatment in to magnetic facsimiles of those cranes. The study showed that the catalytic mechanisms derived from controlled systems and described in the literature can be transferred to synthetic concepts beyond the lab without loss of generality. Once the processes determining the transformation of cellulose into functional materials were understood, the concept could be extended to other metals and metal-combinations. Firstly, the procedure was utilised to produce different ternary iron carbides in the form of MxFeyC (M = W, Mn). None of those ternary carbides have thus far been produced in a nanoparticle form. The next part of this work encompassed combinations of iron with cobalt, nickel, palladium and copper. All of those metals were also probed alone in combination with cellulose. This produced elemental metal and metal alloy particles of low polydispersity and high stability. Both features are something that is typically not associated with high temperature syntheses and enables to connect the good size control with a scalable process. Each of the probed reactions resulted in phase pure, single crystalline, stable materials. After showing that cellulose is a good stabilising and separating agent for all the investigated types of nanoparticles, the focus of the work at hand is shifted towards probing the limits of the structuring and pattering capabilities of cellulose. Moreover possible post-processing techniques to further broaden the applicability of the materials are evaluated. This showed that, by choosing an appropriate paper, products ranging from stiff, self-sustaining monoliths to ultra-thin and very flexible cloths can be obtained after high temperature treatment. Furthermore cellulose has been demonstrated to be a very good substrate for many structuring and patterning techniques from origami folding to ink-jet printing. The thereby resulting products have been employed as electrodes, which was exemplified by electrodepositing copper onto them. Via ink-jet printing they have additionally been patterned and the resulting electrodes have also been post functionalised by electro-deposition of copper onto the graphitised (printed) parts of the samples. Lastly in a preliminary test the possibility of printing several metals simultaneously and thereby producing finely tuneable gradients from one metal to another have successfully been made. Starting from these concepts future experiments were outlined. The last chapter of this thesis concerned itself with alternative synthesis methods of the iron-carbon composite, thereby testing the robustness of the devolved reactions. By performing the synthesis with partly dissolved scrap metal and pieces of raw, dry wood, some progress for further use of the general synthesis technique were made. For example by using wood instead of processed cellulose all the established shaping techniques available for wooden objects, such as CNC milling or 3D prototyping, become accessible for the synthesis path. Also by using wood its intrinsic well defined porosity and the fact that large monoliths are obtained help expanding the prospect of using the composite. It was also demonstrated in this chapter that the resulting material can be applied for the environmentally important issue of waste water cleansing. Additionally to being made from renewable resources and by a cheap and easy one-pot synthesis, the material is recyclable, since the pollutants can be recovered by washing with ethanol. Most importantly this chapter covered experiments where the reaction was performed in a crude, home-built glass vessel, fuelled – with the help of a Fresnel lens – only by direct concentrated sunlight irradiation. This concept carries the thus far presented synthetic procedures from being common laboratory syntheses to a real world application. Based on cellulose, transition metals and simple equipment, this work enabled the easy one-pot synthesis of nano-ceramic and metal nanoparticle composites otherwise not readily accessible. Furthermore were structuring and patterning techniques and synthesis routes involving only renewable resources and environmentally benign procedures established here. Thereby it has laid the foundation for a multitude of applications and pointed towards several future projects reaching from fundamental research, to application focussed research and even and industry relevant engineering project was envisioned.
Die vorliegende Arbeit beschäftigt sich mit der Synthese und Strukturierung von Nanokompositen, d.h. mit ausgedehnten Strukturen, welche Nanopartikel enthalten. Im Zuge der Arbeit wurde der Mechanismus der katalytischen Graphitisierung, ein Prozess, bei dem ungeordneter Kohlenstoff durch metallische Nanopartikel in geordneten (graphitischen) Kohlenstoff überführt wird, aufgeklärt. Dies wurde exemplarisch am Beispiel von Zellulose und Eisen durchgeführt. Die untersuchte Synthese erfolgte durch das Lösen eines Eisensalzes in Wasser und die anschließende Zugabe von so viel Zellulose, dass das die gesamte Eisensalzlösung aufgenommen wurde. Die so erhaltene Mischung wurde anschließend unter Schutzgas innerhalb kürzester Zeit auf 800 °C erhitzt. Hierbei zeigte sich, dass zu Beginn der Reaktion Eisenoxidnanopartikel (Rost) auf der Oberfläche der Zellulose entstehen. Beim weiteren Erhöhen der Temperatur werden diese Partikel zu Eisenpartikeln umgewandelt. Diese lösen dann kleine Bereiche der Zellulose auf, wandeln sich in Eisenkarbid um und scheiden graphitischen Kohlenstoff ab. Nach der Reaktion sind die Zellulosefasern porös, jedoch bleibt ihre Faserstruktur vollkommen erhalten. Dies konnte am Beispiel eines Origamikranichs gezeigt werden, welcher nach dem Erhitzen zwar seine Farbe von Weiß zu Schwarz verändert hatte, ansonsten aber seine Form vollkommen beibehält. Aufgrund der eingebetteten Eisenkarbid Nanopartikel war der Kranich außerdem hochgradig magnetisch. Basierend auf dieser Technik wurden außerdem winzige metallische Nanopartikel aus Nickel, Nickel-Palladium, Nickel-Eisen, Kobalt, Kobalt-Eisen und Kupfer, sowie Partikel aus den Verbundkarbiden Eisen-Mangan-Karbid und Eisen-Wolfram-Karbid, jeweils in verschiedenen Mischungsverhältnissen, hergestellt und analysiert. Da die Vorstufe der Reaktion flüssig ist, konnte diese mit Hilfe eines einfachen kommerziellen Tintenstrahldruckers strukturiert auf Zellulosepapier aufgebracht werden. Dies ermöglicht gezielt Leiterbahnen, bestehend aus graphitisiertem Kohlenstoff, in ansonsten ungeordnetem (amorphen) Kohlenstoff zu erzeugen. Diese Methode wurde anschließend auf Systeme mit mehreren Metallen übertragen. Hierbei wurde die Tatsache, dass moderne Drucker vier Tintenpatronen beherbergen, ausgenutzt um Nanopartikel mit beliebigen Mischungsverhältnisse von Metallen zu erzeugen. Dieser Ansatz hat potentiell weitreichende Auswirkungen im Feld der Katalyse, da hiermit hunderte oder gar tausende Mischungen simultan erzeugt und getestet werden können. Daraus würden sich große Zeiteinsparungen (Tage anstelle von Monaten) bei der Entwicklung neuer Katalysatoren ergeben. Der letzte Teil der Arbeit beschäftigt sich mit der umweltfreundlichen Synthese der obengenannten Komposite. Hierbei wurden erfolgreich Altmetall und Holzstücke als Ausgangstoffe verwandt. Zusätzlich wurde gezeigt, dass die gesamte Synthese ohne Verwendung von hochentwickeltem Equipment durchgeführt werden kann. Dazu wurde eine sogenannte Fresnel-Linse genutzt um Sonnenlicht zu bündeln und damit direkt die Reaktionsmischung auf die benötigten 800 °C zu erhitzen. Weiterhin wurde ein selbst gebauter Glasreaktor eingesetzt und gezeigt, wie das entstehende Produkt als Abwasserfilter genutzt werden kann. Die Kombination dieser Ergebnisse bedeutet, dass dieses System sich beispielsweise zum Einsatz in Katastrophenregionen eignen würde, um ohne Strom und besondere Ausrüstung vor Ort Wasserfilter herzustellen.

La presente tesis doctoral se ha enfocado en el diseño y la síntesis de un nuevo tipo de materiales compuestos basados en metal-organic frameworks (MOFs) o covalent-organic frameworks (COFs) y nanopartículas inorgánicas y el uso de estos materiales compuestos para la catálisis heterogénea. En el primer capítulo se introduce la familia de materiales compuestos dispersos en/sobre diferentes materiales haciendo especial énfasis en aquellos construidos con MOFs y COFs. En el capítulo 2 se presentan los objetivos generales de la tesis doctoral. En el capítulo 3 se muestran los resultados del artículo “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs” publicado en 2016 en la revista Catalysis Science & Technology. En el mismo se reporta la encapsulación de nanopartículas huecas de Platino y Paladio en el ZIF-8 formando así una serie de materiales compuestos en los cuales el espesor de la cáscara de ZIF-8 era modulada de manera sistemática. En el capítulo 4, nanopartículas híbridas de tipo núcleo-coraza de Au/CeO2 dispersadas en microesféras de UiO-66 han sintetizados usando el método se atomización por secado con flujo continuo. Las propiedades catalíticas combinadas en una única partícula de los nanocristales de CeO2 y Au y la capacidad protectora de las microesféras porosas de UiO-66 hacen que estos materiales compuestos muestren resultados interesantes como catalizadores para la reacción de reducción de monóxido de Carbono. (T50 = 72 °C; T100 = 100 °C) con alta reusabilidad. Los resultados obtenidos han sido incluidos en el artículo. “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C” publicado en la revista Journal of Materials Chemistry A en 2017. Finalmente, en el capítulo 5, hemos demostrado que usando un método en dos pasos se pueden funcionalizar COFs confinando en ellos nanopartículas. La reacción directa entre el 1,3,5-tris(4-aminofenil)benceno y el 1,3,5-benzenetricarbaldehído en presencia de una variedad de nanopartículas metalícas o de óxidos de metal resulta en la encapsulación de estas nanopartículas en un polímero amorfo de iminas-enlazadas con forma de esfera. El Post-tratamiento de estas esferas con ácido acético en reflujo conduce a la obtención de esferas cristalinas de COFs basados en iminas. Además materiales compuestos basados en COF y nanopartículas de Au y Pd han demostrado ser catalíticamente activas. Estos resultados han sido publicados en el artículo “Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method” publicado en la revista Chemistry a European Journal en 2017.
The present PhD Thesis has been dedicated to the design and synthesis of a new type of composites of metal-organic frameworks (MOFs) or covalent-organic frameworks (COFs) with inorganic nanoparticles (iNPs) and the use of these composites for heterogeneous catalysis. In the first chapter, we introduce the family of composites made by supporting iNPs on/in different materials, focusing on those constructed with MOFs and COFs. Then, the general objectives of the Thesis are described in Chapter 2. Chapter 3 shows the results in “The influence of the MOF shell thickness on the catalytic performance of composites made of inorganic (hollow) nanoparticles encapsulated into MOFs”, Catalysis Science & Technology (2016). Herein, we report the encapsulation of hollow Pt or Pd nanoparticles (NPs) into ZIF-8, making a series of composites in which the ZIF-8 shell thickness has been systematically varied. By using these composites as catalysts for the reduction of 4-nitrophenol and Eosin Y, we show that the MOF shell thickness plays a key role in the catalytic performance of this class of composites. In Chapter 4, hybrid core-shell Au/CeO2 NPs dispersed in UiO-66 shaped into microspherical beads are created using the spray-drying continuous-flow method. The combined catalytic properties of nanocrystalline CeO2 and Au in a single particle and the support and protective function of porous UiO-66 beads make the resulting composites show good performances as catalysts for CO oxidation (T50 = 72 °C; T100 = 100 °C) and recyclability. The results are included in the manuscript entitled “Core-shell Au/CeO2 nanoparticles supported in UiO-66 beads exhibiting full CO conversion at 100 °C”, Journal of Materials Chemistry A (2017). Finally, in Chapter 5, we demonstrated a two-step method that enables imparting new functionalities to COFs by nanoparticle confinement. The direct reaction between 1,3,5-tris(4-aminophenyl)benzene and 1,3,5-benzenetricarbaldehyde in the presence of a variety of metallic/metal-oxide nanoparticles resulted in the embedding of the nanoparticles in amorphous and nonporous imine-linked polymer organic spheres. Post-treatment reactions of these polymers with acetic acid under reflux led to crystalline and porous imine-based COF- hybrid spheres. Interestingly, porous imine-based COF-hybrids with Au and Pd NPs were found to be catalytically active. These results have been reported in the publication entitled “Confining Functional Nanoparticles into Colloidal Imine-Based COF Spheres by a Sequential Encapsulation-Crystallization Method”. Chemistry a European Journal (2017).

Inorganic-polymer hybrid materials have a high potential to enable major advances in material performance in a wide range of applications. This research focuses on characterizing and tailoring the physics and chemistry of inorganic-polymer interfaces in fabricating high-performance zeolite-polymer mixed-matrix membranes for energy-efficient gas separations. In addition, the topic of novel metal nanoparticle-coated polymer microspheres for optical applications is treated in the Appendix. In zeolite/polymer mixed-matrix membranes, interfacial adhesion and interactions between dope components (zeolite, polymer and solution) play a crucial role in determining interfacial morphology and particle dispersion. The overarching goal is to develop accurate and robust tools for evaluating adhesion and interactions at zeolite-polymer and zeolite-zeolite interfaces in mixed-matrix membrane systems. This knowledge will be used ultimately for selecting proper materials and predicting their performance. This project has two specific goals: (1) development of an AFM methodology for characterizing interfacial interactions and (2) characterization of the mechanical, thermal, and structural properties of zeolite-polymer composites and their correlation to the zeolite-polymer interface and membrane performance. The research successfully developed an AFM methodology to determine interfacial interactions, and these were shown to correlate well with polymer composite properties. The medium effect on interactions between components was studied. We found that the interactions between two hydrophilic silica surfaces in pure liquid (water or NMP) were described qualitatively by the DLVO theory. However, the interactions in NMP-water mixtures were shown to involve non-DLVO forces arising from bridging of NMP macroclusters on the hydrophilic silica surfaces. The mechanism by which nanostructured zeolite surfaces enhanced in zeolite-polymer interfacial adhesion was demonstrated to be reduced entropy penalties for polymer adsorption and increased contact area. ¡¡¡¡¡¡Metal nanoparticle (NP)-coated polymer microspheres have attracted intense interest due to diverse applications in medical imaging and biomolecular sensing. The goal of this project is to develop a facile preparation method of metal-coated polymer beads by controlling metal-polymer interactions. We developed and optimized a novel solvent-controlled, combined swelling-heteroaggregation (CSH) technique. The mechanism governing metal-polymer interaction in the fabrication was determined to be solvent-controlled heteroaggregation and entanglement of NPs with polymer, and the optical properties of the metal/polymer composite beads were shown to make them useful for scattering contrast agent for biomedical imaging and SERS (Surface-Enhanced Raman Scattering) substrates.

Starting from an overview of the basic concepts on the correlation between structural and optical parameters of plasmonic nanostructures, this work presents the results of the synthesis processes and structural, optical and electrical characterizations of metal-based complex morphology and composition nano-composite materials (such as Au Dendrites, SiO2 Nanowires-Au Nanoparticles pea-podded composites, glass/textured_FTO/Au NPs multilayer). The aim is to assess the state of the art and, then, show the innovative contributions that can be proposed in this research field. Opportune methodologies, based on self-organization, have been developed for the production of such materials. Several microscopic techniques have been used to analyze the structural properties of the synthesized materials (i.e. RBS, SEM, AFM, TEM, EDX, EELS), and macroscopic measurements have been used to probe their electrical and optical properties. To understand the growth dynamic and the evolution of these complex systems, the correlation between structural and optical parameters has been established, and phenomenological growth models have been drafted. The entire work has been focused on the research of innovative, versatile and low-cost synthesis techniques, suitable to provide a good control on the size, surface density and geometry of the complex nanostructures. Such optimization of the structural parameters is necessary to modulate the metallic nanostructures optical and electrical properties for each specific application. Therefore, the aim of this study is the fabrication of functional nano-scale-size materials, whose properties can be tailored, in a wide range, simply by controlling the structural characteristics. Optimized optical and electrical properties are required to improve the performance of new photovoltaic devices, biosensors, nano-scale optical devices, sensors and SERS active-substrates.

Foundry aluminum alloys play a fundamental role in several industrial fields, as they are employed in the production of several components in a wide range of applications. Moreover, these alloys can be employed as matrix for the development of Metal Matrix Composites (MMC), whose reinforcing phases may have different composition, shape and dimension. Ceramic particle reinforced MMCs are particular interesting due to their isotropic properties and their high temperature resistance. For this kind of composites, usually, decreasing the size of the reinforcing phase leads to the increase of mechanical properties. For this reason, in the last 30 years, the research has developed micro-reinforced composites at first, characterized by low ductility, and more recently nano-reinforced ones (the so called metal matrix nanocomposite, MMNCs). The nanocomposites can be obtained through several production routes: they can be divided in in-situ techniques, where the reinforcing phase is generated during the composite production through appropriate chemical reactions, and ex situ techniques, where ceramic dispersoids are added to the matrix once already formed. The enhancement in mechanical properties of MMNCs is proved by several studies; nevertheless, it is necessary to address some issues related to each processing route, as the control of process parameters and the effort to obtain an effective dispersion of the nanoparticles in the matrix, which sometimes actually restrict the use of these materials at industrial level. In this work of thesis, a feasibility study and implementation of production processes for Aluminum and AlSi7Mg based-MMNCs was conducted. The attention was focused on the in-situ process of gas bubbling, with the aim to obtain an aluminum oxide reinforcing phase, generated by the chemical reaction between the molten matrix and industrial dry air injected in the melt. Moreover, for what concerns the ex-situ techniques, stir casting process was studied and applied to introduce alumina nanoparticles in the same matrix alloys. The obtained samples were characterized through optical and electronic microscopy, then by micro-hardness tests, in order to evaluate possible improvements in mechanical properties of the materials.

The two major topics studied in this dissertation are the gold(I) pyrazolate trimer {[Au(3-R,5-R’)Pz]3} complexes in aqueous chitosan polymer and phosphorescent polymeric nanoparticles based on platinum(II) based complex. The first topic is the synthesis, characterization and optical sensing application of gold(I) pyrazolate trimer complexes within aqueous chitosan polymer. A gold(I) pyrazolate trimer complex, {[Au(3-CH3,5-COOH)Pz]3}, shows high sensitivity and selectivity for silver ions in aqueous media, is discussed for optical sensing and solution-processed organic light emitting diodes (OLEDs) applications. Gold(I) pyrazolate trimer complexes are bright red emissive in polymeric solution and their emission color changes with respect to heavy metal ions, pH and dissolved carbon dioxide. These photophysical properties are very useful for designing the optical sensors. The phosphorescent polymeric nanoparticles are prepared with Pt-POP complex and polyacrylonitrile polymer. These particles show excellent photophysical properties and stable up to >3 years at room temperature. Such nanomaterials have potential applications in biomedical and polymeric OLEDs. The phosphorescent hybrid composites are also prepared with Pt-POP and biocompatible polymers, such as chitosan, poly-l-lysine, BSA, pnipam, and pdadmac. Photoluminescent enhancement of Pt-POP with such polymers is also involved in this study. These hybrid composites are promising materials for biomedical applications such as protein labeling and bioimaging.

Les matériaux hybrides organique/inorganiques ont reçu beaucoup d'attention ces dernières années dans les études des nanomatériaux. En effet, ils possèdent des propriétés physiques et chimiques uniques grâce aux effets synergiques de chaque composant. En particulier, les nanoparticules de silice (SiO2) présentent des caractéristiques intéressantes, comme une bonne stabilité chimique et thermique. Elles peuvent être préparées de différentes tailles et peuvent aussi être facilement fonctionnalisées. Les polymères conducteurs intrinsèques comme le polythiophène et la polyaniline (PANI) peuvent exister sous différents états d'oxydation et donc répondre à des stimuli extérieurs en changeant une de leur caractéristique (couleur, conductivité, etc…). La PANI est un polymère non-toxique, thermiquement stable et peu coûteux avec une conductivité relativement élevée qui a été utilisée comme film antistatique, matériel d'électrode, inhibiteur de corrosion et comme surface sensible de capteur. Depuis la découverte des polymères conducteurs en 1977, plusieurs travaux ont été effectués sur la préparation, la caractérisation et les applications de films polymériques construits à la surface de matériaux comme la silice. Parmi les différents types de composites existants, les particules de type cœur@coquille composées d’un cœur inorganique et d’une couronne de polymère sont les plus prometteurs. Dans cette étude, nous avons donc décidé de travailler sur la synthèse de composites cœur@coquille constitués d’une coquille de PANI et d’un cœur de particules de silice.Dans la littérature, en utilisant des protocoles expérimentaux similaires, deux morphologies très contradictoires ont été obtenues après la polymérisation par oxydation chimique d'aniline en présence de particules de silice : cœur@coquille et framboise (structure inversée avec la PANI comme cœur). Nous avons alors décidé de réexaminer la synthèse de PANI en présence de particules de silice. Pour cela, nous avons, dans un premier temps, synthétisé des particules de silice monodisperses de différentes tailles (300, 160 et 90 nm) par procédé Stöber. Nous avons ensuite réalisé la polymérisation chimique de l'aniline en présence de ces particules de silice dans des conditions contrôlées afin de promouvoir une adsorption des ions aniliniums en surface des particules. Différents paramètres expérimentaux ont été étudiés tels que la température, la concentration en réactifs, la taille des particules… Les résultats en termes de morphologie sont discutés en fonction de ces paramètres. Dans un second temps, nous avons fonctionnalisé la surface des particules de silice par un alcoxysilane afin de favoriser la polymérisation de l’aniline à la surface des particules. Ainsi, nous avons obtenu des structures SiO2@PANI avec une épaisseur de polymère contrôlable. La dernière partie de ce travail traite des premiers essais qui ont été réalisés afin d’utiliser ces composites SiO2@PANi pour des applications environnementales. Deux applications ont notamment été envisagées, l'adsorption de métaux pour l'aspect de particule et la détection de gaz pour les capacités conductrices de la PANI
Organic/inorganic hybrid materials have received much attention in recent years such as in the field of nano-materials. Indeed, these materials possess unique physical and chemical properties due to the synergistic effect of both components. In particular, silica nanoparticles (SiO2) present interesting properties, such as good chemical and thermal stabilities. They can be prepared in different size and can be easily chemically modified. Intrinsically conducting polymers such as polythiophene and polyaniline (PANI) can exist in different oxidation states and respond to external stimuli by changing one of their characteristics (color, conductivity, …). PANI is a non-toxic, thermally stable and low cost polymer with relatively high conductivity that has been used as antistatic coating, electrode materials, corrosion inhibitor and active layer of sensors. Since the discovery of conducting polymer in 1977, several works have been carried out on the preparation, characterization and applications of polymeric films build on various surfaces like silica. Among the different kinds of composites that exist, inorganic-polymer core-shell nanoparticles are more promising candidates. In this study, we decided to work on the synthesis of core@shell hybrid compounds based on PANI shells and silica nanoparticles cores.In the literature, using similar experimental protocols, two morphologies have been obtained after chemical polymerization of aniline in the presence of silica particles: core@shell and raspberry (inverted structure with PANI as core). We thus decided to reinvestigate the synthesis of PANI in the presence of silica particles. For this, we first synthesized silica particles with different sizes by Stöber process. We then performed the chemical polymerization of aniline in the presence of these naked silica particles under different conditions: temperature, concentration of reactive. However, in all cases, we never managed to obtain core@shell structures. Finally, we succeed in developing a method to prepare these core@shell particles which relies on the functionalization of the SiO2 by alkoxysilanes followed by the polymerization of aniline at room temperature. A series of core-shell particles with tunable PANI thickness has been prepared by this method. The last part of this work deals with the first tests that have been carried out in order to use these composites SiO2@PANi for environmental applications. Two applications have been considered, the adsorption of metals for the particle appearance and the detection of gas for the conductive capacities of the PANI

Ce travail a concerné l'étude de la fonctionnalisation métallique et du contrôle morphologique de nanoparticules de silice mésoporeuse appelées MSN. La voie de fonctionnalisation par synthèse directe a été privilégiée et a consisté en une encapsulation des précurseurs métalliques dans la phase porogène. L'insertion de cuivre, palladium, platine, argent or et de bimétalliques Cu/Pd et Pd/Pt a été réalisée. Il résulte de cette approche une localisation des nanoparticules métalliques dans les pores et d'une grande accessibilité des fonctionnalités à l'origine des excellentes performances catalytiques mesurées. Ces performances et le recyclage du catalyseur Cu@MSN ont été démontrés pour des réactions de Huisgen et de Sonogashira. Il a également été étudié l'adsorption de l'iode moléculaire en phase gaz sur des MSN fonctionnalisées par des nanoparticules d'argent avec d'excellentes capacités de rétention
The objective of this thesis was to develop efficient synthesis routes to prepare mesoporous silica-based nano-sized particles, designated as MSN, with controllable morphology and derivatised with selected transition metals. One-pot preparation and surface functionalisation procedures based on the insertion of the metal-phase precursor into the porogen aggregates were thoroughly optimised leading to silica particles containing such single metals as copper, palladium, platinum, silver or gold, as well as a two-metal phase of copper and palladium or that of palladium and platinum. It was demonstrated that the highly dispersed metal phase was localised on the pore surface and therefore it was readily accessible to the target chemicals on which to base the catalytic performance of the resulting materials. Among others, the remarkable catalytic performance of the Cu@MSN material in Huisgen and Sonogashira reactions and its propensity to undergo efficient recycling were proven through laboratory-scale testing. Experimental study of the selective adsorption of iodine vapour onto MSN supports functionalised with silver nanoparticles indicated an excellent retention capacity of such materials

World population is continuously growing, as well as the influence we have on the ecosystem’s natural equilibrium. Moreover, such growth is not homogeneous and it results in an overall increase of older people. Humanity’s activity, growth and aging leads to many challenging issues to address: among them, there are the spread of suddenly and/or chronic diseases, malnutrition, resource pressure and environmental pollution. Research in the novel field of biodegradable soft robotics and electronics can help dealing with these issues. In fact, to face the aging of the population, it is necessary an improvement in rehabilitation technologies, physiological and continuous monitoring, as well as personalized care and therapy. Also in the agricultural sector, an accurate and efficient direct measure of the plants health conditions would be of help especially in the less-developed countries. But since living beings, such as humans and plants, are constituted by soft tissues that continuously change their size and shapes, today’s traditional technologies, based on rigid materials, may not be able to provide an efficient interaction necessary to satisfy these needs: the mechanical mismatch is too prohibitive. Instead, soft robotic systems and devices can be designed to combine active functionalities with soft mechanical properties that can allow them to efficiently and safely interact with soft living tissues. Soft implantable biomedical devices, smart rehabilitation devices and compliant sensors for plants are all applications that can be achieved with soft technologies. The development of sophisticated autonomous soft systems needs the integration on a unique soft body or platform of many functionalities (such as mechanical actuation, energy harvesting, storage and delivery, sensing capabilities). A great research interest is recently arising on this topic, but yet not so many groups are focusing their efforts in the use of natural-derived and biodegradable raw materials. In fact, resource pressure and environmental pollution are becoming more and more critical problems. It should be completely avoided the use of in exhaustion, pollutant, toxic and non-degradable resources, such as lithium, petroleum derivatives, halogenated compounds and organic solvents. So-obtained biodegradable soft systems and devices could then be manufactured in high number and deployed in the environment to fulfil their duties without the need to recover them, since they can safely degrade in the environment. The aim of the current Ph.D. project is the use of natural-derived and biodegradable polymers and substances as building blocks for the development of smart composite materials that could operate as functional elements in a soft robotic system or device. Soft mechanical properties and electronic/ionic conductive properties are here combined together within smart nanocomposite materials. The use of supersonic cluster beam deposition (SCBD) technique enabled the fabrication of cluster-assembled Au electrodes that can partially penetrate into the surface of soft materials, providing an efficient solution to the challenge of coupling conductive metallic layers and soft deformable polymeric substrates. In this work, cellulose derivatives and poly(3-hydroxybutyrate) bioplastic are used as building blocks for the development of both underwater and in-air soft electromechanical actuators that are characterized and tested. A cellulosic matrix is blended with natural-derived ionic liquids to design and manufacture completely biodegradable supercapacitors, extremely interesting energy storage devices. Lastly, ultrathin Au electrodes are here deposited on biodegradable cellulose acetate sheets, in order to develop transparent flexible electronics as well as bidirectional resistive-type strain sensors. The results obtained in this work can be regarded as a preliminary study towards the realization of full natural-derived and biodegradable soft robotic and electronic systems and devices.

Eletrônica utilizando polímero em substituição ao silício é uma área de pesquisa recente com perspectivas econômicas promissoras. Compósitos de polímeros com partículas metálicas apresentam interessantes propriedades elétricas, magnéticas e ópticas e têm sido produzidos por uma grande variedade de técnicas. Implantação iônica de metais utilizando plasma é um dos métodos utilizados para obtenção desses compósitos condutores. Neste trabalho é realizada implantação de íons de ouro de baixa energia em PMMA utilizando plasma. O PMMA tem grande importância tecnológica sendo largamente utilizado como resiste em litografias por feixe de elétrons, raios-X, íons e deep-UV. Como resultado da implantação iônica de baixa energia em PMMA há formação de uma camada nanométrica de material condutor. Esse novo material, denominado compósito isolante-condutor, permite criar micro e nanodispositivos através de técnicas largamente utilizadas em microeletrônica. Medidas elétricas são realizadas in situ em função da dose de íons metálicos implantada, o que permite um estudo das propriedades de transporte desses novos materiais, que podem ser modeladas pela teoria da percolação. Simulações utilizando o programa TRIDYN permitem obter a profundidade e o perfil da implantação dos íons. São mostradas caracterizações importantes tais como Microscopia Eletrônica de Transmissão, Microscopia de Varredura por Tunelamento, Espalhamento de Raios-X a Baixos Ângulos, Difração de Raios-X e Espectroscopia UV-vis. Essas técnicas permitem visualizar e investigar o caráter nanoestruturado do compósito metal-polímero. Ainda como parte deste projeto, as camadas condutoras formadas no polímero são caracterizadas quanto à manutenção das suas características de elétron resiste.
Electronics using polymers instead of silicon is a recent research area with promising economic perspectives. Polymer with metallic particles composites presents interesting electrical, magnetic and optical properties and they have been produced by a broad variety of techniques. Metal ion implantation using plasma is one of the used methods to obtain conductor composites. In this work it is performed low energy gold ion implantation in PMMA by using plasma. PMMA has great technological importance once it is broadly used as resist in electron-beam, X-ray, ion and deep UV lithography. As a result of low energy ion implantation in PMMA, a nanometric conducting layer is formed. This new material, named insulator-conductor composite, can allow the creation of micro and nanodevices through well known microelectronics techniques. Electrical measurements are performed in situ as a function of metal ions implanted dose, which allows the investigation of electrical transport of these new materials, which can be modeled by the percolation theory. Simulations using TRIDYN computer code provide the prediction of depth profile of implanted ions. Important characterizations are showed such as Transmission Electron Microscopy, Scanning Tunneling Microscopy, Small Angle X-Ray Scattering, X-Ray Diffraction and UV-vis Spectroscopy. These techniques allow to visualize and to investigate the nanostructured character of the metal-polymer composite. Still as a part of this project, the conducting layers formed are characterized in relation to the maintenance of their characteristics as electron-beam resist.

博士
國立成功大學
化學工程學系碩博士班
92
This dissertation concerns the preparation of metal nanoparticles and core-shell composite nanoparticles. In the former, nickel and copper nanoparticles have been prepared in ethylene glycol and aqueous surfactant systems. The preparation conditions and product properties were investigated. In the latter, Ni@Au core-shell composites nanoparticles were prepared in ethylene glycol system and covalently bound with methotrexate (MTX). 　　In ethylene glycol system containing trace bases, Ni nanoparticles could be prepared by hydrazine reduction without the input of extra inert gases and the addition of protective agent. FTIR analysis revealed the formation of a protective layer from ethylene glycol and the Ni-catalyzed decomposition products, which prevented from the agglomeration of particles. The TEM, high-resolution TEM, XRD, electron diffraction pattern, magnetic analyses indicated the resultant particles were pure Ni nanoparticles with the mean diameter of 6-9 nm, fcc structure, and superparamagnetic property. With increasing N2H5OH concentration, The mean diameter decreased and approached a constant when [N2H5OH]/[NiCl2]>20. In addition, hydrazine was catalytically decomposed to hydrogen and nitrogen gases by the resultant Ni nanoparticles. The decomposition rate was 3.1 nmol/h mg Ni at 1 atm and 25℃. 　　In a pure aqueous CTAB solution containing trace bases, Ni nanoparticles could be prepared by hydrazine reduction without the input of extra inert gases. the synthesis of nickel nanoparticles without inert gases was studied. TGA study suggested the formation of a bi-layer structure on particle surface, which prevented from the agglomeration of particles. The TEM, high-resolution TEM, XRD, electron diffraction pattern, magnetic analyses indicated the resultant particles were pure Ni nanoparticles with mean diameters of 10-14 nm, fcc structure, and a superparamagnetic property. With increasing N2H5OH concentration, the mean diameter decreased and approached a constant when [N2H5OH]/[NiCl2]>20. 　　In a pure aqueous CTAB solution, Cu nanoparticles could be prepared by hydrazine reduction without the input of extra inert gases. The key point was the use of ammonia solution to adjust the solution pH up to 10. The concentration of Cu2+ ions allowable was as high as 0.2 M. TGA study suggested the formation of a bi-layer structure on particle surface, which prevented from the agglomeration of particles. The TEM, XRD, electron diffraction pattern, UV-VIS spectrum, and XPS analyses indicated the resultant particles were pure Cu nanoparticles with mean diameter of 5-15 nm and fcc structure. With increasing N2H5OH concentration, the mean diameter decreased and approached a constant when [N2H5OH]/[NiCl2]>40. 　　In ethylene glycol, Ni@Au core-shell composites nanoparticles were prepared. In the absence of protective agent, particle agglomeration was observed. In the presence of polyethyleneimine (PEI) as a protective agent, monodisperse Ni@Au composite nanoparticles with a mean diameter of 14.6 nm were obtained. After surface modification, Ni@Au composite nanoparticles were covalently bound with methotrexate (MTX). Averagely 3.63×104 MTX molecules could be bound on each Ni@Au composite nanoparticle.

碩士
國立成功大學
化學工程學系碩博士班
94
Abstract The main objective of the present investigation is to synthesize and characterize the nanocomposites consisting of metal particles and conducting polymers. Aniline or 2,5-dimethoxyaniline(DMA) is used as monomer. AgNO3, CH3SO3Ag or H2PtCl6 is used as oxidant or precursor of metal. First, PDMA-Ag composite is successfully obtained by oxidative polymerization of DMA in poly(styrene sulfonic acid)(PSS) using AgNO3 or CH3SO3Ag as oxidant. In-situ UV-Vible spectroscopy results show that the growth rate of PDMA is strongly affected by NO3 - and CH3SO3 -. The coupling reaction of PDMA and NO3 – was proposed to explain the lower growth rate of PDMA and by using AgNO3 than CH3SO3Ag as oxidant. X-ray photoelectron spectroscopy and FTIR spectroscopy were used to validate the proposed coupling reaction by monitoring the side product and oxidant state of PDMA. The results show that there are more side products and lower oxidized states for the composite structure in the presence of NO3 – than CH3SO3 -, being agreeable to the proposal. Transmission electron microscopy shows that Ag nanoparticles have almost the same size irrespective of anions. Second, composite consisting of Ag or Pt particles and polyaniline nanofibers is successfully obtained by interfacial polymerization and illuminate UV light. CH3SO3Ag or H2PtCl6 is used as precursor of metal. Transmission electron microscopy shows that the polyaniline nanofibers are about 10~40 nm, Ag or Pt particles are about 5~10 nm. Nanocomposites are characterize by FTIR spectroscopy and Thermal Gravimetric Analysis. The result show that the oxidized states almost the same size irrespective of oxidant or precursors of metals. And nanocomposites are more thermal stable than polyaniline nanofibers. The composite consisting of Pt particles can also use as catalyst to oxidant methanol.

碩士
國立成功大學
化學系碩博士班
98
Green chemistry has received considerable attention in recent years, using benign nature sources as reagents to synthesize practical materials have become more ideal. Gelatin a natural polymer is denatured collagen. Due to many amino-functional groups, gelatin can attach to surface of different materials via hydrogen bonds that makes gelatin a superior protector. Most important, gelatin is a nontoxic, highly biocompatible and low cost reagent, which demonstrates its promising applications in materials synthesis. From our previous reports, mesoporous silicas were facilely prepared by using gelatin as organic templates and sodium silicate as silica precursor at proper pH. In this study, we also use the gelatin as a protecting agent for nanoparticles. With similar synthetic procedures, the mesoporous silica containing different metal nanoparticles and silver halides were prepared. In addition, gelatin can also be used as template to get high-yield mesoporous silica spheres in a narrow particle-size distribution under a environmental friendly synthetic condition. In practical applications, the mesoporous silicas containing gold and platinum nanoparticles were used in the surface enhanced Raman scattering (SERS) applications. The mesoporous silicas containing silver halide nanoparticles is able to be potential photo-catalyst. The highly dispersed silica spheres displayed photonic crystal characters.

Niniejsza rozprawa doktorska została poświęcona zagadnieniom związanym z elektrochemiczną syntezą materiałów kompozytowych zawierających polimery przewodzące oraz nanocząstki metali. Głównym celem podjętych badań było opracowanie lepszych galwanicznych metod otrzymywania kompozytów oraz wyjaśnienie mechanizmu tworzenia się krystalitów metali na powierzchni warstw zbudowanych z polimerów przewodzących. Dotychczas największą kontrolę składu wytwarzanych materiałów uzyskiwano osadzając polimer i metal z osobnych roztworów. Stąd też jednym z zaplanowanych zadań było opracowanie prądowej metody syntezy kompozytów pozwalającej wytwarzać materiały o zróżnicowanej zawartości polimeru i metalu przy wykorzystaniu tylko jednego roztworu. Cel ten został osiągnięty na przykładzie elektroosadzania kompozytu PPy-Au. Dużą uwagę poświęcono badaniu mechanizmu tworzenia fazy metalicznej na warstwach polimerowych. Sprzeczne doniesienia literaturowe opisujące miejsce powstawania zarodków metali na porowatych błonach polimerowych stanowiły motywację do dokładniejszego zbadania procesu osadzania się metali na polimerach przewodzących. Pojawiające się w ostatnich latach w literaturze doniesienia wskazujące na częściową dezaktywację powierzchni metali szlachetnych w wyniku działania wolnych rodników stały się inspiracją do zbadania możliwości wykorzystania trawienia podłoży metalicznych, węglowych i polimerowych rodnikami, jako nowego czynnika mogącego w istotny sposób wpływać na przebieg procesu nukleacji metali na podłożach. W pierwszym rozdziale zawarto krótkie wprowadzenie w podjętą tematykę badawczą oraz przedstawiono główne cele, które zostały sformułowane a następnie realizowane w trakcie przeprowadzonych prac badawczych. W rozdziale drugim przybliżono tematykę kompozytów polimer przewodzący-metal. Opisano w nim najważniejsze właściwości polimerów przewodzących, nanocząstek metali i materiałów kompozytowych oraz nakreślono najbardziej interesujące obszary ich potencjalnego wykorzystania. W rozdziale tym zostały również przedstawione najczęściej stosowane bezprądowe oraz prądowe metody wytwarzania kompozytów zawierających polimery przewodzące i nanocząstki metali. Rozdział trzeci poświęcono zagadnieniom związanym z procesem nukleacji metali na podłożach stałych. Przedstawiono w nim dwa najczęściej wykorzystywane w galwanotechnice modele opisujące mechanizm powstawania i wzrostu zarodków metali na płaskich podłożach: model Scharifkera-Hills’a oraz model Scharifkera-Mostany’ego. Jednocześnie wskazano najczęściej napotykane przez badaczy trudności związane z ich praktycznym wykorzystaniem. W tym rozdziale przedstawiono również czynniki, które mogą wpływać na przebieg procesu osadzania metali. Na koniec krytycznej analizie poddano opisane w literaturze nieliczne próby zastosowania modeli nukleacji metali do scharakteryzowania procesu powstawania krystalitów metali na warstwach polimerowych. W rozdziale czwartym przybliżono problematykę wpływu wolnych rodników na aktywność metali wykorzystywanych powszechnie jako materiały elektrodowe w elektrochemii, w tym w analizie chemicznej i w elektrokatalizie. Jednocześnie wskazano obszary potencjalnego zastosowania warstw kompozytowych, w których materiały te mogą być narażone na niekorzystne oddziaływanie rodników. Przedstawiono również popularne metody otrzymywania wolnych rodników w warunkach laboratoryjnych. Rozdział piąty zawiera spis odczynników chemicznych stosowanych w pracy oraz opis aparatury wykorzystanej zarówno w procesie elektroosadzania kompozytów polimer przewodzący-metal, jak i charakterystyce wytwarzanych materiałów. Przedstawiono w nim także zwięzłą charakterystykę metod badawczych wykorzystywanych w trakcie realizacji pracy. Uzyskane wyniki eksperymentalne zostały przedstawione w rozdziałach od szóstego do ósmego. Rozdział szósty zawiera wyniki badań poświęconych mechanizmowi procesu elektrochemicznego osadzania metali na cienkich porowatych warstwach polimerowych. Badania zostały przeprowadzone dla dwóch układów: polipirol-srebro i polipirol-złoto. W pierwszej części rozdziału opisano opracowaną w trakcie realizacji pracy odtwarzalną procedurę otrzymywania i kondycjonowania warstw PPy. Jej zastosowanie pozwalało wyeliminować zjawisko niekontrolowanego bezprądowego osadzania srebra na polimerze i umożliwiło dokonanie wiarygodnej analizy procesu nukleacji srebra na polipirolu. Następnie na podstawie otrzymanych wyników szczegółowej analizy SEM depozytów Ag i Au osadzanych na błonach polipirolu w różnych warunkach potencjałowych, w sposób jednoznaczny zidentyfikowano miejsce powstawania zarodków metalu osadzanego na porowatych warstwach dobrze przewodzącej formy polimeru. Określono jednocześnie wpływ nadpotencjału redukcji jonów metalu na miejsce formowania się jego zarodków. Zaproponowano także graficzny model ilustrujący przebieg procesu powstawania fazy metalicznej na warstwach polimerowych. W rozdziale szóstym została ponadto zaprezentowana nowa metoda elektroosadzania kompozytów polimer przewodzący-metal, umożliwiająca wytwarzanie materiałów o dowolnej zawartości obu komponentów z jednego roztworu. Ideą zaproponowanej metody było wykorzystanie trwałych inetrnych kompleksów jonów metalu takich jak Au(CN)_2^-, dzięki czemu możliwe było uzyskanie stabilnego roztworu zawierającego jednocześnie pirol i jony metalu. Ze względu na różne zakresy potencjałowe odpowiadające reakcjom elektropolimeryzacji i osadzania złota, opracowany układ pozwalał w sposób niezależny osadzać na powierzchni elektrod polimer oraz metal. Podczas optymalizacji procedury osadzania kompozytu wykazano, że zastosowanie technik pulsowych do osadzania warstw PPy-Au w znacznym stopniu zwiększało homogeniczność otrzymywanych materiałów. W rozdziale siódmym przedstawiono wyniki badań dotyczących procesu nukleacji srebra na podłożach metalicznych (złoto, platyna) oraz węglu szklistym, poddanych wcześniej działaniu wolnych rodników generowanych w reakcji Fentona. Zaobserwowano, że gęstość nukleacji metalu na każdym z badanych podłoży, wyznaczana elektrochemicznie oraz techniką SEM, malała wraz z wydłużaniem czasu kontaktu podłoża z rodnikami. Powyższa zależność wskazywała na spadek aktywności powierzchni metali i węgla szklistego wystawionych na działanie rodników, jak również na brak możliwości wykorzystania rodników w celu polepszenia procesu osadzania metali na takich podłożach. Uzyskane w tych eksperymentach zależności posłużyły do porównań z procesami nukleacji metalu na modyfikowanych rodnikami warstwach polimeru. W rozdziale ósmym zamieszczone zostały rezultaty badań, których celem było określenie wpływu działania wolnych rodników na strukturę i właściwości katalityczne kompozytów polipirol-złoto. Porównanie prądów utleniania etanolu zarejestrowanych z użyciem warstw kompozytowych traktowanych roztworem Fentona przez różny czas wykazało, że wraz z wydłużaniem czasu kontaktu kompozytów z rodnikami maleje aktywność tych materiałów. Przyczyną pogorszenia się właściwości katalitycznych warstw PPy-Au było sukcesywne trawienie powierzchni struktur złota przez rodniki. Ponadto w tym rozdziale została zaproponowana nowatorska metoda elektrochemicznego otrzymywania kompozytów polimer przewodzący-metal polegająca na osadzaniu metalu na powierzchni błon polimerowych poddanych wcześniej działaniu rodników. Analiza procesu nukleacji srebra na podłożach polimerowych trawionych rodnikami wykazała wzrost ilości miejsc aktywnych na powierzchni polimeru. W przypadku kompozytów PPy-Au wytworzonych tą metodą obserwowano większe rozdrobnienie i lepszą jednorodność krystalitów metalu. Co jednak najważniejsze, ściany kryształów złota osadzanego na warstwach PPy trawionych rodnikami przez krótki czas charakteryzowały się zwiększoną obecnością różnych nanostruktur, a tak wytworzone kompozyty wykazywały lepsze właściwości katalityczne. W rozdziale dziewiątym i dziesiątym przedstawiono kolejno podsumowanie i streszczenie pracy. Rozdział jedenasty stanowi spis publikacji powstałych w trakcie realizacji pracy doktorskiej, natomiast w rozdziale dwunastym zawarto bibliografię.
The main objective of the study was to develop improved galvanic methods of preparation of the composites containing conductive polymers and metal nanoparticles. The other important scientific aim was to clarify the mechanism of the formation of metal crystallites on the surface of the conducting polymer layers. To date the greatest control of the composition of the produced materials was obtained by depositing the polymer and metal from separate solutions. That is why one of the scheduled tasks was to develop a current-controlled method of synthesis of the composites allowing the formation of the materials with desired content of polymer and metal using only one plating solution. This was achieved for the electrodeposition of PPy-Au composite. Special attention was paid to the studies of the mechanism of formation of the metallic phase on the polymer layers, since contradictory reports exist in the literature on the location of nucleation of metals on porous polymer layers. In the presented work detailed studies of nucleation of metals on polymer films were performed. The obtained results were confronted with the literature data. Other important aspect of performed investigations was to describe the influence of electrochemical activity of the electrode surface on the mechanism and rate of the nucleation process. In recent years in the literature some reports appeared on the partial deactivation of the surface of precious metals as a result of free radicals attack. This became the inspiration for examining the nucleation of metals on the substrates treated with radicals. The first thesis chapter contains an introduction to the subject of the research and presentation of the main objectives that have been formulated and realized in the course of carried out research work. In the second chapter, the issues related with the conductive polymers-metal composites are introduced. This part describes the most important properties of conducting polymers, nanoparticles of metals and composite materials and outlines the most interesting areas of their potential application. This chapter also presents the most commonly used electroless and current methods used for preparation of composites containing conductive polymers and metal nanoparticles. The third chapter is devoted to topics related to the process of nucleation of metals on solid substrates. It presents two models describing the mechanism of formation and growth of metal nuclei on a flat surface: Scharifker-Hills model and Scharifker-Mostany model. They are the most commonly used models in electroplating. It also indicates often encountered problems associated with their practical use. The influence of such factors like temperature, overpotential and quality of the substrate on the metal deposition process is also discussed here. Finally, the critical analysis of described in the literature few attempts to apply the above models to characterize the nucleation of metals on the polymer layers is presented. The fourth chapter describes the phenomena related to the influence of free radicals on the activity of metals commonly used as electrode materials. The presented results include chemical analysis and changes of electrocatalytic properties of various materials. It also indicates the areas of potential application of composite layers in which these materials may be exposed to the aggressive environment containing radicals. Finally it presents popular methods of obtaining free radicals under laboratory conditions. In fifth chapter, a list of chemicals used in the work and the description of the apparatus used in the electrodeposition and characteristics of composites containing a conducting polymer and metal are presented. It also presents a brief description of experimental methods used in the laboratory work. The obtained experimental results are presented in chapter sixth, seventh and eighth. Chapter sixth presents the results of the studies on the mechanism of electrochemical deposition of metals on thin porous polymer layers. The measurements were carried out for two systems: polypyrrole-silver and polypyrrole-gold. The first part of the chapter describes developed in the course of the work a reproducible procedure for obtaining and conditioning the PPy layers. Its application allowed to eliminate the phenomenon of uncontrolled electroless deposition of silver on the polymer and allowed a reliable analysis of the process of silver nucleation on polypyrrole. The identification of the place of formation of metal deposited on porous layers of well-conductive form of the polymer was done on the basis of the results of a detailed SEM analysis of Ag and Au deposited on polypyrrole layers at different potentials. Moreover, the correlation between the overpotential of reduction of metal ions and place of the formation of the metal nuclei was analyzed. A graphical model illustrating the process of the formation of the metallic phase on the polymer layers was proposed. The sixth chapter also presents a new method for electrodeposition of the conducting polymer-metal composites, allowing the formation of materials of any content of the two components using one solution. The idea of the proposed method was the use of strong inert complexes of the metal ion such as Au(CN)_2^- what allowed obtaining a stable solution containing both pyrrole and metal ions. The different potential ranges corresponding to the reactions of electro-polymerization and deposition of gold allow avoiding the redox reaction between the noble metal ion and the monomer. Finally the independent deposition of polymer and metal on the electrode surface was possible. During the optimization of the deposition procedure it has been shown that the use of pulse technique for the electrodeposition of PPy-Au layers significantly increased the homogeneity of the obtained materials. The seventh chapter presents the results of research on the process of nucleation of silver on metal (gold, platinum) and glassy carbon, all treated with free radicals generated in the Fenton reaction. It was observed that the density of nucleation of metal on each of the substrates, measured using electrochemical methods and SEM, decreased with prolongation of the contact of substrates with OH˙ radicals. This dependence indicated the decrease in the activity of metals and glassy carbon surfaces treated with radicals, as well as the inability to use the radicals to improve the metal deposition process on those substrates. The results obtained were compared with those on the processes of nucleation of the metal on the polymer layers etched with radicals. In this case OH˙ radicals activated the surface and the nucleation process was accelerated. In the eighth chapter, the results of studies aimed at determining the effect of free radicals on the structure and catalytic properties of polypyrrole-gold composite are presented. The currents of ethanol oxidation were recorded using the composite layers treated with Fenton solution for various time. It revealed that the activity of these materials decreases with increasing time of contact with the radicals. The cause of the deterioration of the catalytic properties of PPy-Au layers was the successive etching of the surface of gold crystallites by the radicals. However, it was found that the presence of a PPy layer on the electrode limited the deactivation of gold nanostructures. Furthermore, this chapter describes a novel method for electrochemical preparation of composites containing conductive polymer and metal. The proposed method involves the deposition of a metal on the surface of polymer films pre-treated with Fenton solution. The analysis of the process of nucleation of silver on the polymer substrates etched with the radicals indicated an increase in number of the active sites on the polymer surface. In the case of PPy-Au composites produced by this method, smaller and more uniform metal crystallites were obtained. But most importantly, the walls of gold crystals deposited on PPy layers exposed to the radicals for a short time showed an increased presence of the different nanostructures. This resulted in better catalytic properties of the composites. The thesis ends with a summary and a list of references.

The growing incidences of orthopedic problems globally have created a huge demand for strong bioactive materials for bone tissue engineering. Over the years, studies have shown chemical, physical, and mechanical properties of biomaterials influence the cellular interactions at the material-tissue interface, which subsequently controls biological response to materials. Strong biomaterials with surface properties that actively direct cellular response hold the key for engineering the next generation orthopedic implants. With its unique properties graphene can be used to reinforce poly (ε-caprolactone) (PCL) to prepare strong and bioactive polymer nanocomposites for bone tissue regeneration. The thesis entitled ―Engineering bioactive and multifunctional graphene polymer composites for bone tissue regeneration” systematically studies the effect of different chemically functionalized and metal-graphene hybrid nanoparticles in PCL composites for bone tissue engineering. The thesis comprises of seven chapters. Chapter 1 is an outline review on the impact of graphene and graphene derived particles to prepare supporting substrates for tissue regeneration and the associated cell response to multifunctional graphene substrate. This chapter discusses how cells interact with different graphene based particles and the interplay between cells performance and multifunctional properties of graphene based substrates. Chapter 2 describes the role, if any, of the functionalization of graphene on mechanical properties, stem cell response and bacterial biofilm formation. PCL composites of graphene oxide (GO), reduced GO (RGO) and amine-functionalized GO (AGO) were prepared at different filler contents (1%, 3% and 5%). Although the addition of the nanoparticles to PCL markedly increased the storage modulus, this increase was higher for GO and AGO than with RGO. In vitro cell studies revealed that the AGO and GO particles significantly increased human mesenchymal stem cell (hMSC) proliferation. AGO was most effective in augmenting stem cell osteogenesis leading to mineralization. Bacterial studies revealed that interaction with functionalized GO induced bacterial cell death due to membrane damage which was further accentuated by amine groups in AGO. The synergistic effect of oxygen containing functional groups and amine groups on AGO-reinforced composites renders the optimal combination of improved modulus, favorable stem cell response and biofilm inhibition desired for orthopaedic applications. In Chapter 3, toward preparing strong multi-biofunctional materials, poly(ethylenimine) (PEI) conjugated graphene oxide (GO_PEI) was synthesized using poly(acrylic acid) (PAA) as spacer and incorporated in PCL at different fractions. GO_PEI significantly promoted proliferation and formation of focal adhesions in hMSCs on PCL. GO_PEI was highly potent in inducing stem cell osteogenesis leading to 90% increase in alkaline phosphatase activity and mineralization over neat PCL with 5% filler content and was 50% better than GO. Remarkably, 5% GO_PEI was as potent as soluble osteo-inductive factors. Increased adsorption of osteogenic factors due to the amine and oxygen containing functional groups on GO_PEI augment stem cell differentiation. GO_PEI was also highly efficient in imparting bactericidal activity with 85% reduction in counts of E. coli colonies compared to neat PCL at 5% filler content and was more than twice as efficient as GO. This may be attributed to the synergistic effect of the sharp edges of the particles along with the presence of the different chemical moieties. Thus, in contrast to using labile biomolecules, GO_PEI based polymer composites can be utilized to prepare bioactive resorbable biomaterials for fabricating orthopedic devices for fracture fixation and tissue engineering. Chapter 4 describes the preparation of hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and its advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) nanoparticles were synthesized by facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200 – 300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared incorporating RGO_Sr particles in PCL. The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare scaffolds with osteoinductive property. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Chapter 5 discusses the use of hybrid graphene-silver particles (RGO_Ag) to reinforce PCL and compared with PCL/RGO and PCL/Ag composites containing RGO and silver nanoparticles (AgNPs), respectively. RGO_Ag hybrid particles were well dispersed in the PCL matrix unlike the RGO and AgNPs due to enhanced exfoliation. RGO_Ag led to 77 % increase in the modulus of PCL and provided a conductive network for electron transfer. Electrical conductivity increased four orders of magnitude from 10-11 S/cm to 10-7 S/cm at 5 wt % filler that greatly exceeded the improvements with the use of RGO and AgNP in PCL. RGO_Ag particles reinforced in PCL showed sustained release of silver ions from the PCL matrix unlike the burst release from PCL/Ag. PCL/RGO_Ag and PCL/RGO composites were non-toxic to hMSCs and supported osteogenic differentiation unlike the PCL/Ag composites which were highly toxic at ≥3% filler content. The PCL/RGO_Ag composites exhibited good antibacterial effect due to a combination of silver ion release from the AgNPs and the mechanical rupture induced by the RGO in the hybrid nanoparticles. Thus, the synergistic effect of Ag and RGO in the PCL matrix uniquely yielded a multifunctional material for use in implantable biomedical devices and tissue engineering. Chapter 6 presents investigation of potential differences in the biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Results showed that osteoblast response to graphene in polymer nanocomposites is markedly altered between 2D substrates and 3D scaffold due to the roughness induced by the sharp edges of graphene at the surface in 3D but not in 2D. Osteoblast organized into aggregates in 3D scaffolds in contrast to more well spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D scaffolds compared to 2D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route. Chapter 7 summarizes the important results and future directions of the work. This chapter provides general conclusions arising from this study, and makes suggestions for future work designed to provide a greater understanding of the in vivo response in terms of bio-distribution of the released functionalized graphene from the scaffold or substrate must be assessed with special attention on their accumulation or excretion.

The growing incidences of orthopedic problems globally have created a huge demand for strong bioactive materials for bone tissue engineering. Over the years, studies have shown chemical, physical, and mechanical properties of biomaterials influence the cellular interactions at the material-tissue interface, which subsequently controls biological response to materials. Strong biomaterials with surface properties that actively direct cellular response hold the key for engineering the next generation orthopedic implants. With its unique properties graphene can be used to reinforce poly (ε-caprolactone) (PCL) to prepare strong and bioactive polymer nanocomposites for bone tissue regeneration. The thesis entitled ―Engineering bioactive and multifunctional graphene polymer composites for bone tissue regeneration” systematically studies the effect of different chemically functionalized and metal-graphene hybrid nanoparticles in PCL composites for bone tissue engineering. The thesis comprises of seven chapters. Chapter 1 is an outline review on the impact of graphene and graphene derived particles to prepare supporting substrates for tissue regeneration and the associated cell response to multifunctional graphene substrate. This chapter discusses how cells interact with different graphene based particles and the interplay between cells performance and multifunctional properties of graphene based substrates. Chapter 2 describes the role, if any, of the functionalization of graphene on mechanical properties, stem cell response and bacterial biofilm formation. PCL composites of graphene oxide (GO), reduced GO (RGO) and amine-functionalized GO (AGO) were prepared at different filler contents (1%, 3% and 5%). Although the addition of the nanoparticles to PCL markedly increased the storage modulus, this increase was higher for GO and AGO than with RGO. In vitro cell studies revealed that the AGO and GO particles significantly increased human mesenchymal stem cell (hMSC) proliferation. AGO was most effective in augmenting stem cell osteogenesis leading to mineralization. Bacterial studies revealed that interaction with functionalized GO induced bacterial cell death due to membrane damage which was further accentuated by amine groups in AGO. The synergistic effect of oxygen containing functional groups and amine groups on AGO-reinforced composites renders the optimal combination of improved modulus, favorable stem cell response and biofilm inhibition desired for orthopaedic applications. In Chapter 3, toward preparing strong multi-biofunctional materials, poly(ethylenimine) (PEI) conjugated graphene oxide (GO_PEI) was synthesized using poly(acrylic acid) (PAA) as spacer and incorporated in PCL at different fractions. GO_PEI significantly promoted proliferation and formation of focal adhesions in hMSCs on PCL. GO_PEI was highly potent in inducing stem cell osteogenesis leading to 90% increase in alkaline phosphatase activity and mineralization over neat PCL with 5% filler content and was 50% better than GO. Remarkably, 5% GO_PEI was as potent as soluble osteo-inductive factors. Increased adsorption of osteogenic factors due to the amine and oxygen containing functional groups on GO_PEI augment stem cell differentiation. GO_PEI was also highly efficient in imparting bactericidal activity with 85% reduction in counts of E. coli colonies compared to neat PCL at 5% filler content and was more than twice as efficient as GO. This may be attributed to the synergistic effect of the sharp edges of the particles along with the presence of the different chemical moieties. Thus, in contrast to using labile biomolecules, GO_PEI based polymer composites can be utilized to prepare bioactive resorbable biomaterials for fabricating orthopedic devices for fracture fixation and tissue engineering. Chapter 4 describes the preparation of hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and its advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) nanoparticles were synthesized by facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200 – 300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared incorporating RGO_Sr particles in PCL. The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare scaffolds with osteoinductive property. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration. Chapter 5 discusses the use of hybrid graphene-silver particles (RGO_Ag) to reinforce PCL and compared with PCL/RGO and PCL/Ag composites containing RGO and silver nanoparticles (AgNPs), respectively. RGO_Ag hybrid particles were well dispersed in the PCL matrix unlike the RGO and AgNPs due to enhanced exfoliation. RGO_Ag led to 77 % increase in the modulus of PCL and provided a conductive network for electron transfer. Electrical conductivity increased four orders of magnitude from 10-11 S/cm to 10-7 S/cm at 5 wt % filler that greatly exceeded the improvements with the use of RGO and AgNP in PCL. RGO_Ag particles reinforced in PCL showed sustained release of silver ions from the PCL matrix unlike the burst release from PCL/Ag. PCL/RGO_Ag and PCL/RGO composites were non-toxic to hMSCs and supported osteogenic differentiation unlike the PCL/Ag composites which were highly toxic at ≥3% filler content. The PCL/RGO_Ag composites exhibited good antibacterial effect due to a combination of silver ion release from the AgNPs and the mechanical rupture induced by the RGO in the hybrid nanoparticles. Thus, the synergistic effect of Ag and RGO in the PCL matrix uniquely yielded a multifunctional material for use in implantable biomedical devices and tissue engineering. Chapter 6 presents investigation of potential differences in the biological response to graphene in polymer composites in the form of 2D substrates and 3D scaffolds. Results showed that osteoblast response to graphene in polymer nanocomposites is markedly altered between 2D substrates and 3D scaffold due to the roughness induced by the sharp edges of graphene at the surface in 3D but not in 2D. Osteoblast organized into aggregates in 3D scaffolds in contrast to more well spread and randomly distributed cells on 2D discs due to the macro-porous architecture of the scaffolds. Increased cell-cell contact and altered cellular morphology led to significantly higher mineralization in 3D scaffolds compared to 2D. This study demonstrates that the cellular response to nanoparticles in composites can change markedly by varying the processing route. Chapter 7 summarizes the important results and future directions of the work. This chapter provides general conclusions arising from this study, and makes suggestions for future work designed to provide a greater understanding of the in vivo response in terms of bio-distribution of the released functionalized graphene from the scaffold or substrate must be assessed with special attention on their accumulation or excretion.

碩士
國立中央大學
化學研究所
98
To increase the solubility of graphene in water, we modified the graphene skeleton with sulfonyl groups. With hydrazine as the reducing agent, SB12 as the surfactant in the aqueous phase, platinum and palladium nanoparticles were produced on the graphene plane skeletons, separating the graphene layers. Sample 1 has 56 wt% Pt, with average of metal particle size of 83.2 nm; sample 2 has 14 wt% Pt, with particle size of 27.3 nm; sample 3 has 32 wt% Pd, with particle size of 2.4 nm, and sample 4 has 16 wt% Pd, with particle size of 8.9 nm. Towards hydrogen storage applications, sample 3 performs the best. Under 510 psi hydrogen pressure, the hydrogen uptake reaches 2.19 wt%. The samples 1~4, when used in catalytic hydrogenation of styrene, all gave better than results commercial catalysts. For samples 1、2, they are better than the commercial Pt / C; and for samples 3、4, they are better than the commercial Pd / C. Ionic liquid [HOCH2CH2NH3][HCO2] was used as a solvent, as a reducing agent, and also as a surfactant, converting Pt metal source to Pt nanoparticles under microwave heating conduction. Following are the characteristics of Pt nanoparticles formed on the plane of graphite oxide and graphene. Sample 5 is on the graphene substrate, with Pt 62 wt%, and the average metal particle size of 5.0 nm, sample 7 on the graphite oxide substrate, with Pt 40 wt%, and the average metal particle size of 18.8 nm, and sample 8 on the graphite oxide substrate, containing Pt 1 wt%, and the average metal particle size of 4.7 nm. Samples 5, 7~8 were seen to have a very special cubic shape. Pt nanoparticles in sample 6 on the graphene substrate, with Pt 13 wt%, and the average metal particle size of 14.6 nm were in multiply truncated cubic shape. The rationale is that the ratio between the concentration of reducing agent and that of metal source is too large under the reaction condition, and the formation and the stacking of metal become too fast to grow to crystals properly in a cubic shape. Sample 8 still formed a cubic shaped nanoparticles, presumably that graphite oxide is rich with the oxygen functionalities which regulate the seeding and growth of the Pt nanoparticles in proximity. Sample 5 and 6 were used in the catalytic hydrogenation of styrene. Better results were obtained for 5 and 6 when compared with that of commercial Pt / C.

The thesis consists of four parts of which part 1 presents a brief overview of nanomaterials. Parts 2, 3 and 4 contain results of investigations of graphene, nanofilms of noble metal nanoparticles and ZnO nanostructures respectively. Investigations of graphene are described in Part 2 which consists of six chapters. In Chapter 2.1, changes in the electronic structure and properties of graphene induced by molecular charge-transfer have been discussed. Chapter 2.2 deals with the results of a study of the interaction of metal and metal oxide nanoparticles with graphene. Electrical and dielectric properties of graphene-polymer composites are presented in Chapter 2.3. Chapter 2.4 presents photo-thermal effects observed in laser-induced chemical transformations in graphene and other nanocarbons system. Chapter 2.5 describes the mechanical properties of polymer matrix composites reinforced by fewlayer graphene investigated by nano-indentation. The extraordinary synergy found in the mechanical properties of polymer matrix composites reinforced with two nanocarbons of different dimensionalities constitute the subject matter of Chapter 2.6. Investigations of noble metal nanoparticles have been described in Part 3. In Chapter 3.1, ferromagnetism exhibited by nanoparticles of noble metals is discussed in detail while Chapter 3.2 deals with surface-enhanced Raman scattering (SERS) of molecules adsorbed on nanocrystalline Au and Ag films formed at the organic–aqueous interface. Factors affecting laser-excited photoluminescence from ZnO nanostructures are examined in great detail in Part 4.

The thesis consists of four parts of which part 1 presents a brief overview of nanomaterials. Parts 2, 3 and 4 contain results of investigations of graphene, nanofilms of noble metal nanoparticles and ZnO nanostructures respectively. Investigations of graphene are described in Part 2 which consists of six chapters. In Chapter 2.1, changes in the electronic structure and properties of graphene induced by molecular charge-transfer have been discussed. Chapter 2.2 deals with the results of a study of the interaction of metal and metal oxide nanoparticles with graphene. Electrical and dielectric properties of graphene-polymer composites are presented in Chapter 2.3. Chapter 2.4 presents photo-thermal effects observed in laser-induced chemical transformations in graphene and other nanocarbons system. Chapter 2.5 describes the mechanical properties of polymer matrix composites reinforced by fewlayer graphene investigated by nano-indentation. The extraordinary synergy found in the mechanical properties of polymer matrix composites reinforced with two nanocarbons of different dimensionalities constitute the subject matter of Chapter 2.6. Investigations of noble metal nanoparticles have been described in Part 3. In Chapter 3.1, ferromagnetism exhibited by nanoparticles of noble metals is discussed in detail while Chapter 3.2 deals with surface-enhanced Raman scattering (SERS) of molecules adsorbed on nanocrystalline Au and Ag films formed at the organic–aqueous interface. Factors affecting laser-excited photoluminescence from ZnO nanostructures are examined in great detail in Part 4.

碩士
國立臺北科技大學
化學工程研究所
104
In this work, we used metal nanoparticles with metalloporphyrins decorated reduced graphene oxide composite modified electrode for the electrocatalytic reaction. Considering the nanoparticles, we used that a single step electrochemical fabrication of a PtNPs decorated RGO (RGO-PtNPs) composite for enhanced electrochemical sensing of H2O2 .The fabricated composite modified electrode was further characterized by CV and amperometry methods (i-t) .The amperometric response of the RGO–PtNPs composite modified electrode for the reduction of H2O2 was linear over the concentration ranging from 0.05 μM to 750.6 μM with the limit of detection of 0.016 μM. The sensitivity of the sensor was calculated as 0.686 ±0.072 μM mM-1 cm-2. On the other hand, the metalloporphyrins decorated RGO for the application. RGO supported Mn-TPP nanocomposite was electrochemically synthesized and used for the highly selective and sensitive detection of DA. Besides, the prepared RGO/Mn-TPP nanocomposite modified electrode exhibited an enhanced electrochemical response to DA with less oxidation potential and enhanced response current. The working linear range of the electrode was observed from 0.3 μM - 188.8 μM, the limit of detection was 0.008 μM and the sensitivity was 2.606 μA μM-1 cm-2. In addition, we also reported the preparation and catalytic properties of RGO/Pd-TPP composite modified electrode. The ORR was studied by CV, and LSV. The modified nanocomposite was compared with the commercially purchased Pt/C electrode and shows that the current density was higher than that of the Pt/C electrode with less methanol hindrance. In addition, the prepared composite modified electrode was characterized by the SEM, EIS, NMR, UV, XRD, Infrared Spectroscopic and elemental analysis.

碩士
國立臺北科技大學
化學工程與生物科技系化學工程碩士班
107
Part 1 Methyl paraoxon (MOX) is a highly toxic organophosphate pesticide. It is recently reported that, MOX can enter the human body through ingestion, inhalation, or by dermal penetration. Due to its high non-degradability, it can bind to the tissues of fruits and vegetables. When it is consumed, it can imposes sub-chronic and chronic diseases, by the inhibition of acetylcholinesterase in human metabolism. Therefore, for the first time, we reported a detection of non-enzymatic electrochemical sensor based on 3D porous phase graphene oxide sheets encapsulated chalcopyrite (GOS@CuFeS2) nanocomposite. Hence, the development of reliable sensors for the real-time detection of pesticides is imperative to overcome practical limitations encountered in conventional methodologies. As synthesized GOS@CuFeS2 nanocomposite film screen-printed carbon modified electrode (SPCE) displays excellent electrocatalytic ability towards MOX. Under optimized working conditions, the modified electrode provides linear response range from 0.073 to 801.5 μM. The detection limit was obtained as 4.5 nM. The sensor displayed outstanding sensitivity as 17.97 µA µM–1 cm–2. This composite could be a promising electrode modifier for electrocatalysis. Finally, the GOS@CuFeS2 nanocomposite modified electrode shows greater real-time practicality in vegetable real samples. The obtained moral parameters from the developed method were compared with the authenticated HPLC results. Part 2 At present, B/N co-doped mesoporous carbon (BNDC) have been synthesized in one-step and employed for high sensitive electrochemical detection of Isoniazid (INZ). The synthetic procedure was simple and produced homogenous doping of heteroatoms with high elemental purity, and mesoporous surface. Further, the surface and physiochemical properties of synthesized BNDC was analysis by Nitrogen (N2) adsorption-desorption analysis, and spectroscopic studies. A high sensitive amperometric sensor of BNDC film modified electrode, towards INZ, delivered superior analytical performance with a broad dynamic range 0.02–1783 µM and detection limit of 1.5 nM. Excellency of electrochemical sensor can be attributed to the large surface area, low pore size, abundant active sites, and enhanced electrical conductivity of synthesized BNDC electrocatalyst. Furthermore, the excellent chemical stability of BNDC advocate the long-term stability and reproducibility of the fabricated electrochemical assay. The practical applicability of the proposed sensor was assessed by detection of INZ in physiological fluids. Part 3 The world’s largest aluminium producer has publicized that will blockout aluminum production all over the country from November 2018 to March 2019, in order to minimize winter air pollution. Presumably, these sort of reports urge the chemists to perceive that recovery or recycle of aluminum is decisive. In this article, our group has recovered aluminium oxide nanoparticles (Al2O3 NPs) through a facile one-step sonochemical methodology. The morphological details of Al2O3 NPs were examined by FE-SEM and TEM; finally, the purity of as-recovered Al2O3 NPs were confirmed by XPS and XRD. The as-recovered Al2O3 NPs were employed for the specific and sensitive detection of omeprazole (OMZ), which comes under the class of proton-pump inhibitor. Under the well-optimized conditions, the graphically plotted calibration curve was attained at Al2O3 NPs/GCE towards the detection of OMZ, which possesses the wider linear range of 0.025-433.3 µM, with the minimal detection limit of 9.1 nM. Furthermore, the recovered material was employed as an active participant in supercapacitor application, which exhibited an appreciable specific capacitance value (688 F/g) at 1 A/g current density in 1 M KOH and maintained 86% capacitance retention even after 3000 GCD cycles.

Department of Ecology and Resource Management
PhDENV
Groundwater has traditionally been perceived to be low in chemical species toxicity and microbiologically 'pure'. However, depending on the geological chemistry, formations and anthropogenic activities creating the frequent occurrence of microbiological contamination and excess toxic chemical constituents, the high quality of groundwater as a drinking water source can easily be compromised rendering it unsafe, thus, leading to severe waterborne epidemics. The rapid increase in fluoride and microbial contamination of groundwater have become a global problem to human health. Fluoride in its acceptable concentration in drinking water (< 1.5 mg/L); is known to be beneficial for human growth and development but becomes detrimental at higher concentrations (> 1.5 mg/L) leading to the prevalence of dental and crippling skeletal fluorosis. On the other hand, consumption of microbiologically contaminated water has led to many types of diseases including diarrhea, cholera, typhoid, dysentery and other serious illnesses often leading to millions of deaths annually worldwide. South Africa had experienced water-borne diseases epidemic in the recent past due to failing water treatment facilities in many parts of the country including rural areas. Fluorosis, diarrhea, and cholera are among the chronic health hazards affecting a large population in South Africa. Continuous outbreaks of water-related diseases have been at an unimaginable high level with a reported increase in death rate. The inefficiency of conventional water treatment plants to remove fluoride and disinfect these pathogens from the contaminated domestic and rural community has led to the development of many techniques. These include membrane filtration, ion-exchange, coagulation-precipitation, adsorption among others of which adsorption process proves to be a more significant technology for fluoride removal. Equally, the emergence of nanomaterials has also proved to be the natural answer to solve problems associated with microbes in water since these are absolute barriers to pathogens whose size exceeds most sorbent pore sizes. Also, materials from natural biopolymers or biomass can be utilized at an affordable cost as effective sorbent material for toxic chemical ions and pathogens removal from contaminated water. Consequently, extensive research works have been channeled into the development of more advanced low cost sustainable functionalized sorbent materials and technologies with multifunctional properties for effective water purification. The present study focused on the development of a functionalized chitosan-cellulose hybrid nanocomposite decorated with metal-metal oxides nanoparticles for simultaneous fluoride and microbial removal from groundwater. This was to increase the selectivity and disruption of such pollutants for effective groundwater purification technology. The thesis is presented in nine chapters: (1) General introduction, problem statement, and motivation, research objectives, hypothesis and delimitations of the research are briefly discussed, (2) This chapter gives the literature review of occurrence and sources of fluoride, various fluoride removal techniques; sources, control measures and prevention of microbial pollution in groundwater; the importance of biosynthesis of nanomaterials as emerging novel water treatment adsorbents, the strength of Point-Of-Use as a means of water treatment, water treatment adsorbents synthesis and types of adsorbents with emphasis on hydroxyapatites and biopolymeric based sorbent materials, (3) Optimization of microwave-assisted synthesis of silver nanoparticle by Citrus paradisi peel extracts and its application against pathogenic water strain, (4) Biosynthesis of ultrasonically modified Ag-MgO nanocomposite and Its potential for antimicrobial activity, (5) Green synthesis of Ag/MgO nanoparticle modified nanohydroxyapatite and its potential for defluoridation and pathogen removal in groundwater (6) Green Synthesis of AgMgOnHaP nanoparticles supported on Chitosan matrix: defluoridation and antibacterial effects in groundwater, (7) Biosynthesis of nanofibrous cellulose decorated Ag-MgO-nanohydoxyapatite composite for fluoride and bacterial removal in groundwater, (8) Defluoridation and removal of pathogens from groundwater by hybrid vi cross-linked biopolymeric matrix impregnated Ag-MgOnHaP nanocomposite (9) Conclusions and Recommendations. It is important to point out that Chapters 3 to 8 contains a collection of the research deliverables produced in forms of paper publications and manuscripts and are summarized in a systemic order of experimental protocol. This first output (Chapter 3) of this study evaluated the optimization of a time-dependent microwave-assisted biosynthesis of silver nanoparticles using aqueous peel extracts of Citrus paradisi (Grapefruit red) as a reducing, stabilizing and capping agent with emphasis on its antibacterial property. Optical, structural and morphological properties of the synthesized Citrus paradisi peel extract silver nanoparticle (CPAgNp) were characterized using UV-visible spectrophotometer, transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Brunauer–Emmett–Teller (BET) and X-ray diffractometer (XRD). The antimicrobial activity was evaluated using the well- and disc-diffusion as well as microdilution methods. Characteristic surface plasmon resonance (SPR) wavelength in the range of 420-440 nm at an optimized intensity growth rate typical of silver nanoparticles was obtained. Microwave irradiation accelerates the reaction medium within seconds of nucleation compared to conventional heating methods of synthesis. The influence of the reaction mixtures affected the SPR patterns on the different nucleation, stability and nanoparticle growth. The mixing ratio of 2:3 (C. paradisi peel extracts: 1 mM AgNO3) was chosen as the optimum reaction mixing ratio relative to the bio-reduction intensity of SPR process contributing to the particle size growth of CPAgNps. The presence, interaction and shifting of the functional groups in the FT-IR spectra of biosynthesized CPAgNps indicated that bioactive compounds present in C. paradisi peel extract were responsible for the bio-reduction of the silver ion to silver nanoparticles. The electron micrographs of the synthesized CPAgNps showed a face-centered cubic (FCC) unit phase structure, spherically-shaped nanoparticles size of 14.84 ± 5 nm with a BET pore diameter of 14.31 nm. The use of biological material allowed the control of the size and stability of the nanoparticle but was obtained in low quantity. The Citrus paradisi peel extract mediated AgNp were found to possess a broad-spectrum antimicrobial activity against water-borne pathogenic microbes in the order: Escherichia coli > Staphylococcus aureus > Klebsiella pneumonia. In Chapter 4, a synergistic bi-layered Ag-MgO nanocomposite from Ag and MgO precursor salts using a natural source from the waste product (citrus fruits outer cover) as a reducing and capping agent was successfully synthesized by a simple rapid, integrated bio-mediated microwave and ultrasonic methods. This was carried out to investigate the interfacial interaction and the encapsulated growth rate behind their combination in obtaining an enhanced antibacterial activity against common water fecal pathogen (Escherichia coli). The growth sequence, structural and morphology interface as well as the composition of the nanocomposite were examined and evaluated by the different characterization techniques. The respective potential application as an antimicrobial agent was evaluated and compared against Escherichia coli. The bio-mediated core-shell Ag-MgO nanocomposite showed characteristic synergetic UV-visible absorption bands at 290 nm for MgO nanoparticle and at around 440 nm for Ag nanoparticle, which moved to a lower wavelength of 380 nm in the composite. The shifting to a lower wavelength confirmed the reduction in the particle size as influenced by the growth rate optical property of biomolecular capped Ag-MgO nanocomposite from the phytochemical constituents in the peel extract of the Citrus paradisi. FTIR analysis further elaborated the role of the organic moieties in the Citrus paradisi extracts acting as the capping and stabilizing agent in the formation of the core-shell Ag-MgO nanocomposite. SEM analysis revealed an agglomeration of layered clustered particles, which was poly-dispersed while XRD showed the cubical crystal lattice network phase structure of the Ag-MgO nanocomposite. The TEM micrograph vii showed a structurally uniform and spherical biosynthesized Ag-MgO nanocomposite with a diameter of about 20–100 nm with an average particle size of 11.92 nm. The bi-layered Ag-MgO nanocomposite exhibited a higher level broad-spectrum of antibacterial potential on E. coli with 22 mm zone of inhibition and MIC of 20 (μg/mL) in comparison with the Ag (9 mm; 40 μg/mL) and MgO (9 mm; 80 μg/mL) nanoparticles. The leaching and toxicity level of the time-dependent releases of metal ions indicates that the effluents contain a lower concentration of Ag and Mg ions as compared to World Health Organization permissible limit of < 100 ppb (Ag). The biosynthesized Ag-MgO nanocomposite exhibited an enhanced antibacterial activity synergistic effect against E. coli than Ag and MgO nanoparticles, thus, proving to be a potential disinfect material against common pathogens in water treatment. Chapter 5 presented the biosynthesis, characterization, and assessment of simultaneous fluoride and pathogen removal potential in aqueous solutions of a multi-layered Ag-MgO/nanohydroxyapatite (Ag-MgOnHaP) composite. The successful incorporation of Ag-MgO into nanohydroxyapatite (Ag-MgOnHaP) sorbent via an in-situ solution-gelation (sol-gel) method was ascertained from UV-visible absorption spectrum bands at 290 and 440-378 nm typical of MgO and Ag nanoparticles combination in Ag-MgOnHaP composite. FTIR analysis showed the main surface functional groups involved to be –OH, C=N, carbonate and phosphate species on the backbone of Mg-O-Mg vibrational mode. The hydroxyl and amine groups indicated the interaction of a variety of metabolites components present in citrus peel extract as bio-reductive compounds associated with the Ag-MgO and also in fluoride ion exchange. SEM, TEM images and XRD analysis showed a well-dispersed discretely embedded layered-spherical Ag-MgOnHaP nanocomposite without any form of agglomeration after ultrasound exposure ranging in size from 20 to 100 nm with an average mean particle size diameter of 16.44 nm. The high purity of the synthesized Ag-MgOnHaP nanocomposite was confirmed by the presence Ag, Mg and O impregnated on the nanohydroxyapatite template from EDS spectrum analysis. Batch sorption studies using the nanocomposite under different experimental parameters were conducted and optimized. Equilibrium fluoride adsorption capacity of 2.146 mg/g at 298 K was recorded with more than 90% fluoride removal at optimized conditions of 60 min, 10 mg/L initial F- concentration, 0.3 g/L dosage, and pH 6 at 250 rpm. pHpzc of Ag-MgOnHaP nanocomposite was established to be 8. The equilibrium data were best fitted to the Freundlich isotherm model and followed the pseudo-second-order kinetics model at room temperature. The presence of competing anions such as Cl−, NO3−, does not have an impact on percentage fluoride uptake efficiency, but SO42− and CO32− reduce the F- removal efficiency. Moreover, as the concentration of the co-anions increased, fluoride adsorption uptake decreases. The biosynthesized nanohydroxyapatite incorporated Ag/MgO nanoparticle adsorbent (Ag-MgOnHaP) showed strong antibacterial activity against Escherichia coli and Klebsiella pneumonia when compared to hydroxyapatite alone. The presence and interaction between the Ag, MgO nanoparticles with the respective bacterial genomes was suggested to have accounted for this bioactivity. The synthesized Ag-MgOnHaP sorbent was found to portray a better sorption capacity compared to other adsorbents of similar composition in the literature and could be successfully regenerated with 0.01 M NaOH with fluoride removal of 74.24% at the 4th cycle of re-use. The impregnation of metal-metal oxide nanoparticles on sustainable natural biopolymers from waste products was presented in Chapters 6, 7 and 8. The use of these sustainable natural biopolymers (chitosan and cellulose) was targeted with more emphasis on surface functionalization, improved structural diversity and improved specific surface area with the sole aim of increasing the adsorptive capacity of fluoride ions as well as antimicrobial properties. The selected polymers were chosen because of their biodegradability, viii non-toxicity, renewability, selectivity and abundance in nature, which makes them promising starting materials for the purpose of sustainable water treatment. Chapter 6 presents the successful sol-gel biosynthesis, characterization, potential application for fluoride and pathogens removal from aqueous solution using Ag-MgOnHaP embedded on a chitosan polymer backbone (AgMgOnHaP@CSn) sorbent material. The overall formation of the AgMgOnHaP@CSn nanocomposite from different surface functionalization precursors and phases were supported by the various characterization methods such as UV–vis spectroscopy, SEM-EDS, FTIR, TEM, and Brunauer–Emmett–Teller (BET) techniques. Batch fluoride sorption experiments were conducted to assess fluoride uptake efficiency through optimization of several operational parameters such as contact time, adsorbent dosage, initial pH and co-competing anions. The antimicrobial activity of the synthesized AgMgOnHaP@CSn nanocomposites was also determined. The presence and bio-reduction processes of both Ag and MgO chemical species due to the interaction and coordination of bonds within the bioactive functional species of the polymer matrix was confirmed by the emergence of a sharp peak appearing at around 290 nm to a broad plateau plasmon absorbance above 440 nm on the AgMgOnHaP@CSn nanocomposite. FTIR analysis further supported the presence of the main bioactive functional species to be –OH, –NH2 CO32−, PO43-, Mg–O-Mg amongst other groups on the material surface. SEM and TEM displayed homogeneously dispersed particles within the aggregated biopolymeric composite with a diameter ranging between 5-30 μm. Pore sizes were observed to be in the micro-mesoporous range with an average size of about 35.36 nm and a pore diameter of 33.67 nm. The optimized conditions were as follows: 30 mins contact time, a dose of 0.25 g/50 mL, adsorbate concentration of 10 mg/L F-, initial pH 7 while adsorption capacity decreases with increase in temperature. AgMgOnHaP@CSn composite has a pHpzc value of ≈ 10.6 and the maximum sorption capacity was established to be 6.86 mg/g for 100 mg/L F- concentration at 303 K. The effect of co-existing anions was observed to be of the following order: Cl- < NO3- < SO42- << CO32-. The fluoride sorption experimental data was well described by Langmuir adsorption isotherm while the sorption reaction mechanisms were diffusion-controlled and followed the pseudo-second-order sorption model. F- sorption process could best be described as a combination of ligand exchange, electrostatic attraction, and improved structural surface modification. The antimicrobial susceptibility analysis through the zone of inhibition (mean and standard deviation) showed the potency to pathogens of the following order: Staphylococcus aureus > Escherichia coli. Chapter 7 gives an insight into the development of cellulose nanofibrous matrix (isolated from saw-dust) decorated with Ag-MgO-nanohydroxyapatite (CNF-AgMgOnHaP) and its application in fluoride and pathogen removal from contaminated water. The synthesized CNF-AgMgOnHaP, unlike the cellulose nanofiber, showed characteristic absorption bands in UV–vis spectroscopy between 270-290 nm typical of MgO together with a broad band around 420 nm associated with the characteristic of silver nanoparticles. FTIR spectrometry suggested the presence of nanohydroxyapatite (nHaP) and MgO species impregnation within the CNF matrix. SEM, TEM, XRD, and EDS analysis showed a well-established structural and morphological modifications between cellulose nanofiber alone, biosynthesized CNF-AgMgOnHaP and fluoride sorbed CNF-AgMgOnHaP nanocomposite. A granulated aggregation of micro-mesoporous particles with an improved BET surface area of 160.17 m²/g was developed. Optimum fluoride sorption capacity was 8.71 mg/g for 100 mg/L F- solution at 303 K. F- sorption capacities decreased as the operating temperatures increases. Optimum F- removal of 93 % was achieved at optimum conditions established: pH 5, solid/liquid ratio of 0.25 g/ 50 mL, 10 mg/L F-, contact time 10 min, temperature 25 ± 3 °C and shaking speed of 250 rpm. Percent F- removal decreased with increasing initial adsorbate concentration. The pHpzc value of the CNF-AgMgOnHaP occurred at ≈ 4.7. Co-existing ions were observed to have an effect on the adsorption of F- in the following order: NO3- < Cl- < SO42- < S. aureus > K. pneumonia. The antibacterial potency increased with increasing sorbent concentration. In chapter 8, Defluoridation and antimicrobial activity of synthesized cross-linked cellulose-chitosan impregnated with the developed nanomaterial (AgMgOnHap) are presented. The before and after fluoride sorption by the synthesized CECS@nHapAgMgO nanocomposites were characterized using several physical and chemical techniques which include, BET, SEM-EDS, TEM, XPS, XRD, and FTIR. The overall batch fluoride sorption processes and adsorption capacity through optimization of different experimental sorption parameters, sorption isotherms, and kinetic mechanisms as well as antibacterial potency were studied and reported. SEM and TEM analysis showed densely irregular multiple-layered structures, homogeneous deposition of the AgMgOnHaP on the polymeric matrices. Equilibrium fluoride sorption capacity on CECS@nHapAgMgO sorbents showed an increased affinity of 26.11 mg/g for 150 mg/L F- solution at 313 K.at optimized conditions of 40 min contact time, dosage of 0.3 g and pH of 5. The pH point of zero charge was found to be 7.27. The reaction pathway model sequence of fitness follows the order Pseudo first order < Elovich < Pseudo-second order kinetic model while intra-particle diffusion model and mass transfer of fluoride molecules from the external surface onto the improved pores of the adsorbent were found to be involved in the rate-controlling step. Although both non-linear Langmuir and Freundlich isotherms showed appropriate trends in the F- sorption process, the adsorption isotherm data were better fitted to the non-linear Freundlich isotherms models, suggesting stronger heterogeneous adsorption onto the active binding sites of the CECS@nHapAgMgO surface. The fluoride sorption was observed to be a favorable process across the operating temperatures. Temkin heat of sorption (BT) and the mean free adsorption energy (E) of the D-R isotherm model was within the range of 0.68-3.39 J/mol and 1.58 -7.45 kJ/mol respectively. The fluoride sorption process was observed to be temperature-dependent; while adsorption capacities (Qm) and Temkin heat of sorption (BT) increased with increasing temperature, D-R Mean free sorption energy (E) decreased at higher temperatures. The thermodynamic analysis demonstrated that fluoride sorption on the CECS@nHapAgMgO surface was exothermic, feasible and spontaneously inclined with a decrease in the degree of randomness at the sorbate-sorbent interface. The influence of co-existing anions on fluoride removal exhibited the following trend Cl−< NO3− E. Coli > K. pneumonia where the MIC values of 20 μg/mL were recorded for S. aureus and E. Coli respectively and 10 μg/mL for K. pneumonia. Lastly, the applicability of the sorbents was tested with a field water sample collected from a high fluoride borehole water from a local village (Lephalale Municipality of Limpopo province, South Africa). The before and after analysis showed the excellent potential of CECS@nHapAgMgO sorbent in removing fluoride. In conclusion, the successful surface functionalization synthesis of these improved surface area hybrid nano-sorbents supported by the different morphological techniques was found to be effective in creating more surface-active binding sites for fluoride adsorption and disinfection of waterborne pathogens from aqueous solution. The originality of this developed sorbent lies firstly, in the ability to simultaneously remove both chemical and biological water pollutants; secondly, the use of biodegradable, eco-friendly and non-toxic abundance wastes raw materials to develop a water purification material and in solving waste management issues was a key factor towards environmental sustainability. Above all the developed materials were established to possess superior fluoride adsorption capacity when compared to other reported sorbent materials. Lastly, the project findings /innovation will contribute to Sustainable Development Goals (SDG) 3 and 6, aimed at improving clean water supply and health of the communities and the world at large. However, the following recommendations were made following the findings from this study: 1) In order to increase the surface area to volume ratio, greater selectivity, porosity, and mechanical stability of the polymers as well as size-exclusion mechanism without a large energy penalty of the microbes and fluoride ion for effective water treatment, a more effective and an enhanced multifunctional, multi-layer nanofibrous hybrid sorbent through electrospinning techniques should be considered for future work, 2) More studies on the mode of actions and morphological changes in the pathogens leading to the cell death through the influence of the nanocomposites should be further explored, 3) Application of this advanced technology vis-à-vis other biomaterials to generate filter membrane towards efficient microbial removal and deflouridation is a great challenge worth looking at, 4) Lastly, materials developed in the present study should be modeled, tested and fabricated at the point of use for fluoride and pathogen removal at household level.
NRF

博士
國立臺北科技大學
能源與光電材料外籍生專班研究所
102
Highly sensitive and selective novel electrochemical sensors and biosensors were fabricated using various composite modified electrodes, such as carbon nanomaterials/metal oxide and or metal nanoparticles. The reduced graphene oxide (RGO) and a zinc oxide (ZnO) composite modified electrode has been used for the enzyme free detection of hydrogen peroxide (H2O2). Moreover, it also has been used as an immobilization matrix of glucose oxidase to construct the glucose biosensor. The model enzymes such as hemoglobin (HB) and GOx were immobilized at multiwalled carbon nanotubes (MWCNTs) and ZnO composite surface and used for the selective detection of H2O2 and glucose, respectively. Another glucose biosensor and H2O2 has been developed using a hydrothermally synthesized graphene/cobalt oxide nanoparticles (GN/Co3O4-NPs) composite. The electrochemically fabricated RGO/silver nanoparticles (Ag) composite has also been used as an immobilization matrix for GOx. An electrochemical sensor for the selective and simultaneous detection of dihydroxy benzene isomers (hydroquinone (HQ), catachol (CC) and resorcinol (RC) has been fabricated using RGO/copper nanoparticles (RGO/Cu-NPs) composite modified electrode. The direct electrochemistry and electrochemical, electrocatalytic behavior of immobilized GOx and Hb at composite modified electrodes have also been studied in detail. The surface morphology of fabricated composites has been investigated by scanning electron microscopy (SEM) or field emission scanning electron microscopy (FESEM). The selectivity, stability and the practical applications of the developed electrochemical sensors and biosensors have also been studied. The electroanalytical parameters such as sensitivity, linear detection range and detection limit have also been evaluated for the fabricated sensors. In addition, surface coverage concentration (Г) and electron transfer rate constant (Ks) have also been calculated for enzymatic biosensors.

碩士
國立中央大學
材料科學與工程研究所
101
Lithium aluminum hydride (LiAlH4)has high hydrogen density so it’s a potential hydrogen storage materials. In this study, we tried to improve the hydrogen storage properties of LiAlH4 by ball milling process. We introduced different carbon materials, metal/carbon composites, other catalysts. According to Temperature-Programmed Desorption (TPD)analysis, We found that by Supercritical carbon dioxide (scCO2)process synthesized Fe/Graphene composites obviously decreased the dehydrogenation temperature of LiAlH4. It’s catalytic effect better than VCl3, TiO2. By the materials analysis, between air process and scCO2 process, the later is more monodisperse than air process. So size effect and distribution play the most important role to improve catalytic properties. At 100 oC isothermal dehydrogenation dynamics analysis, LiAlH4 (BM30 min)release 4 wt% hydrogen after 10.8 hr while LiAlH4 + 10 wt% Fe/Graphene only need 10 minute. The results of experimental indicate that the Fe/Graphene is the best catalyst for LiAlH4.

An electronic nose is a man-made implementation of an olfactory system that is comprised of an array of broadly cross-reactive sensors. Electronic noses are used in the food industry, environmental monitoring, explosive detection and medical diagnosis. Our laboratory has focused in the development and implementation of arrays of low power, inexpensive chemiresistive thin films, that are able to identify and quantify a diverse collection of vapors and mixtures of vapors. Novel bioinspired sensors, and array chamber architectures are constantly been developed and improved to fulfill the desired performance of such arrays in different applications. This work details the development and the sensing performance of novel sensor materials based on composites of carbon black and metalloporphyrins, and organically-functionalized gold (Au) and titanium (IV) dioxide (TiO₂) nanoparticles.

Composites of carbon black and metalloporphyrin complexes were developed and optimized to sensitively detect and classify a series of organic vapors. Such sensors films also exhibited a high sensitivity towards trace levels of ammonia (NH₃(g)) and 2,4,6-trinitrotoluene (TNT) in air. Such composites broaden the types of materials that can be used for this type of low-power chemiresistive vapor sensing, and broaden the types of analytes that can be sensitively detected to include inorganic gases and explosives, as well as organic vapors.

Au and TiO₂ nanoparticles were synthesized and functionalized with a variety of ligands. These materials allowed for molecular control of the interparticle physicochemical properties such as electron transfer. Details about the performance of each unique functionalized Au or TiO₂ nanoparticle film upon exposure to a variety of organic vapors was described as a function of ligand length, structure and other physicochemical properties. The discrimination performance for arrays of such sensors was also evaluated.

碩士
國立臺灣科技大學
化學工程系
104
In this study, we have developed a facile and effective wet-chemistry-based oxidative process for producing GNRs by lengthwise cutting and unraveling of CNT side walls with a very low usage of concentrated sulfuric acid. By introducing KNO3 in the starting CNT pretreatment, the yield of GNRs can reach nearly 100%. In addition, it is possible to reduce 90% usage of the concentrated H2SO4. The experimental findings presented in this study show that engineering of the inter- and intratube intercalation of CNTs by suitable intercalation molecules is a key factor to achieve not only high-yield GNR synthesis but also low usage of concentrated H2SO4. In addition, we also present a controllable synthesis of Ag/GNR composites with two topics: (i) different functionality of Ag/MWGNRs (ii) different width of Ag/GNRs at the same oxidation degrees. These two syntheses of topics were by a two-step reaction route. First, we synthesized and functionalized GNRs by a facile carbon nanotube chemical unzipping. The functionalization of GNRs could be controlled, confirming by XPS characterizations. Second, Ag NPs can be decorated onto the GNRs surface through a wet-chemical-based redox reaction. Detailed hybrid materials characterizations including UV-Vis spectroscopy show that Ag/GNR composites were successfully synthesized in our experiment. We further systematic studied the Raman response of the Ag/GNR composites using Rhodamine 6G (R6G) as the Raman probe. The result indicates that the Ag/GNR composites show superior SERS performance with low detection concentration of 10-9 M of R6G and high enhance factor (EF) of 3.62×107.

碩士
國立成功大學
機械工程學系
106
Hydroxypropyl methylcellulose (HPMC) is a kind of biopolymer with the character-istics of biodegradability, environment friendly, great mechanical properties and tribological properties. Therefore, it is suitable to develop as substituted materials of plastic. However, HPMC deforms easily when it bears the loading, causing real con-tact area and the adhesive force between HPMC and counter(AISI52100) increase, so that the HPMC film is easily damaged due to adhesive wear, and leading to lose efficacy on wear resistance. Hence, nanoparticles(NPs) Al, Cu, Al2O3, CuO have been used as fillers, by means of procedure, nano- suspension with dispersant (Span80) were prepared, and mixed with HPMC solution to prepare composite solu-tions and composite films. The study examined the basic properties (quality analysis, thickness, surface roughness, morphology), load capacity and macro-scale tribologi-cal behaviors. Results showed that Span80 could provide steric stabilization, and dispersed the NPs effectively in suspension. After suspension mixed with HPMC so-lution, HPMC made composite solution more stable. The load capacity of composite film remarkably enhanced, especially Cu/HPMC composite film. In terms of tribo-logical behaviors, the NPs Al and Cu occur deformation after wear test of low load-ing, the wear resistances had rose. Spherical CuO and sphere-like Al2O3 occurred rolling effect as third-body at interface during the test, so that the coefficient of fric-tion and wear rate decreased significantly. Since HPMC is soluble in water and or-ganic solvents (ethanol, and so on), the composite solution could be separated into additive and solution easily by appropriate pore size of filters, preventing pollution and recycling limited resources.

碩士
國立臺北科技大學
化學工程與生物科技系化學工程碩士班
107
Part 1 Herein, the synthesis of novel non-aggregated spinel nickel ferrite, NiFe2O4 nanosheets (NiFe2O4 NSs) and its application towards the selective electrocatalytic reduction of hydrogen peroxide are described. Initially, NiFe2O4 NSs is synthesized by one-step hydrothermal approach, and numerous characterizations deliberately explain the compound's composition and structure. Finally, the NiFe2O4 NSs underwent direct non-enzymatic electrochemistry and succeeded, it as mimicking Horseradish Peroxidase properties. The significance of non-aggregated NiFe2O4 NSs together with good electrocatalytic properties leads the material to the platform for electrochemical sensors. Moreover, NiFe2O4 NSs is fabricated and validated as an enzyme-free biosensor for the sensitive detection of H2O2. The demonstrated sensor revealed excellent detection of H2O2 with the pico-molar detection limit (12.4 pM), and also it offered good analytical parameters with more extensive linear range and higher sensitivity. Likewise, the non-enzymatic biosensor annexes good durability, reproducibility, and selectivity towards the determination of H2O2. Due to the nourishing capacity of the prepared NiFe2O4 NSs, it is employed for the enzyme-free detection of H2O2 in human blood and rat brain serum samples. Part 2 The diabetes mellitus was reported as one of the leading reasons for death around the world. Consequently, most of the researches were ardent to the detection of blood sugar level. Therefore, the morphology, as well as the sensing properties of renowned materials, should have optimized and engineered for higher sensitivity towards glucose. For the first time, an extensively utilized active component of a glucose sensor, Cuprous oxide (Cu2O) is synthesized and dealt with various annealing temperatures at 400, 600, and 800 ˚C. The impacts of annealing temperatures on morphology, electro-active surface area, and the glucose sensing properties of cuprous oxides are investigated and spotted that, 600 ˚C is an effective annealing temperature. Then, we developed an electrochemical biosensor through the economic SPCE modification method. As a result, the modified electrode showed exceptional electrocatalytic ability towards glucose and the anodic peak current is correlated with the concentrations of glucose. It obtained more extensive working range between 31 nM and 1423 μM and with very low detection limit and appreciable sensitivity. This method is successfully applied to the recognition of glucose level in the samples of human blood serum and whole blood. Part 3 After a long-term toxicity study on Bisphenol A (BPA), the European Union and U.S food and drug administration updating the rules regarding the usage of BPA by extending the prohibition of BPA to include in the production of papers, on February 2018. Therefore, it is essential to establish the trace level BPA detectors in paper samples. In this report, the synthesis of novel ZnO nanoclusters wrapped with reduced graphene oxide (ZnO NCs/rGO) and its application towards the selective electrocatalytic detection of BPA are described. Initially, ZnO NCs/rGO is synthesized by the one-step hydrothermal approach, and various characterizations explains the compound's compositions and structure. The significance of ZnO NCs/rGO together with good electrocatalytic properties leads this material to the platform for electrochemical sensor. Finally, ZnO NCs/rGO was fabricated and validated as an effective sensor for the sensitive detection of BPA. The demonstrated sensor revealed excellent detection of BPA with the very low detection limit (2.1 nM), and also it offered good analytical parameters with more extensive linear range and higher sensitivity. Likewise, the sensor annexes good durability, reproducibility, and selectivity towards the determination of BPA. Due to the nourishing capacity of the prepared ZnO NCs/rGO, it is employed for the detection of BPA in tissue paper samples.