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Gas-phase Fe nanoparticles with a diameter ~ 2nm, have been used in all the nanostructured material in this thesis. In pure Fe nanoparticle systems with different thicknesses, two important parameters the exchange interaction (Hex) and random anisotropy (Hr) were investigated using the Random Anisotropy Model (RAM). This reveals that for the same particle size Hex remains almost constant for varying Fe thicknesses; whereas Hr increases with the increase of Fe film thickness. This is ascribed to increasing strain imposed at the nanoparticle level. The observed high values of Hr are related to an oxide on the cluster surface in these films, whose effect is also observed in low temperature magnetometry data. This shows the appearance of exchange bias in the films. The RAM approach when applied to Fe clusters in Co matrices, reveals much lower values of Hr than found in pure Fe nanoparticles and both Hr and Hex show an increase with the Volume Fraction (VF) of Fe in Co. The increase in Hex is ascribed to the increasing spin moment with Fe volume fraction. The nature of Fe clusters in very thick layers produce a high frequency Ferromagnetic Resonance response in the radio frequency range, which is an important finding for many applications. The EXAFS study of Fe nanoparticles in Cr matrices show no structural modification relative to the bulk bcc structure of both elements. The magnetometry results suggest that in dilute Fe concentration films, the observed decrease in the overall magnetization is due to the development of a nonmagnetic shell at the interface between Fe and Cr at each cluster boundary. This is reinforced by the lack of any evidence of EB. With increasing VF at about 10% of Fe there is strong evidence of the formation of a super-spin-glass (SSG) that shows the characteristic memory effect. Increasing the Fe nanoparticles VF to 20% Fe in Cr, the magnetization exceeds that expected for Fe indicating that the interaction induces some of the Cr to order ferromagnetically. Core-shell nanoparticle systems have been synthesised by a method that allows a complete control over the morphology of these assemblies. Atomic investigations in Fe@Cu CS nanoparticles reveal that Fe nanoparticles adopt the fcc structure with a 20 monolayer Cu shell thickness and stay in the bcc structure for 1-2 monolayer thick Cu shells. No alteration in the Fe atomic structure has been reported for different Au shell thicknesses in Fe@Au. The magnetic data show a reduced magnetization of the FM-AFM Fe@Cr CS nanoparticles as compared to the bulk value which is also ascribed to the formation of a non-magnetic Fe shell at the interface.

The optical response of metallic structures has attracted significant interest for various applications in recent years. Of particular relevance to display applications is the ability to optimize the intensity and wavelength of the radiation which is scattered by the structure. In this thesis, original studies are presented across three main sections which investigate the optical response of a variety of composite structures formed from metal and dielectric elements.

The field of nanotoxicology has emerged as a discipline in parallel with the rapid expansion of nanotechnology and the use of nanomaterials in modern life. Assessing the potential impacts of manufactured nanoparticles (MNPs) on the environment and human health is critical to the sustainable development of the nano-industry. Current knowledge on the ecological implications of nanotoxicology has major uncertainties surrounding the fate and behaviour of nanomaterials in the exposure environment. Bioavailability, uptake and partitioning of nanomaterials to organisms are key determinates to toxicity, yet these foundations of basic data are only now just starting to emerge in any useful and coherent manner for aquatic animals. This thesis work set out to address this gap in knowledge and further our understanding of these important principles for fish. In an attempt to develop a high through-put screening system for toxicity of MNPs, studies assessing the utility of primary isolated rainbow trout (Oncorhynchus mykiss) hepatocytes found they showed very limited responses to a range of MNPs. There was a lack of any evidence for either lipid peroxidation or xenobiotic detoxification activity. In these studies isolated trout hepatocytes were found to be unresponsive to the induction of these biological responses after exposure to positive controls. The findings demonstrated that the MNPs tested showed low toxicity generally and that fish hepatocytes do not provide a useful system for the screening of potential toxic effects of MNPs. In this cell culture work, coherent anti-Stokes Raman scattering (CARS) microscopy was applied to demonstrate that the particles supplied in the culture medium did cross the cell membrane and enter into the exposed cells. In the second phase of the work in this thesis CARS was investigated as an experimental technique for tracing a wide range of metal and metal oxide MNPs into cells and tissues. CARS was applied to evaluate initial detection of different MNPs and investigate the imaging capability on a range of cells, tissues and organisms. Finally, CARS was applied to assess localisation ability of MNPs within biological matrices. MNPs were shown to be taken into trout hepatocytes using a 3D reconstruction to determine the origin of the MNP signal within the cell. Uptake of MNPs was established into trout gill and kidney tissue, corophium and daphnia species and were shown to have different partitioning in zebrafish embryos. In summary CARS showed great potential for tracing particle uptake and bio-distribution both in vitro and in vivo. Particular benefits include imaging MNPs in living organisms, without the need for labelling or fixing the material. Limitations of the CARS technique are also discussed. In chapter 4, the consequences of the presence of natural organic matter (NOM) were investigated on the uptake of MNPs into fish. Carp (Cyprinus carpio) were exposed to cerium dioxide (CeO2) MNPs in combination with NOM over 28 days. Elevated levels of uptake of cerium were measured in the brain, gill and kidney tissue by induction coupled plasma mass spectroscopy (ICP-MS) for fish exposed to 50 μg/l CeO2 MNPs in combination with 250 μg/l of NOM. There were no such effects of the NOM enhancing uptake for the bulk CeO2 particles. Detailed studies on the behaviour of the CeO2 MNPs in the exposure medium demonstrated the highly complex and dynamic nature of the interactions with NOM. This study discusses some of the difficulties in the techniques, analysis and interpretation of data derived from studies of this nature. The finding that NOM may enhance MNP uptake presents a potential issue for current risk assessment criteria for MNPs that do not consider natural conditions. The final experimental chapter considered maternal transfer as a potentially important route for exposure of embryos and early life stage animals to MNPs in live bearing animals. In this work guppies (Poecilia reticulata) were exposed to 7 nm silver citrate stabilised particles and citrate stabilised bulk sized particles, dosed via the diet for a full gestation cycle. Maternal transfer of Ag to the larvae was significantly higher for the nanoparticulate treatment compared with the bulk and control treatments and larval burden was significantly higher compared with the maternal sires. However, there was no impact of Ag on larval survival, birth weights, or on indices of body condition in the exposed adults. The enhanced uptake of nano Ag compared to bulk Ag particles into the guppy offspring emphasises the potential for exposure to sensitive early life stages of organisms, which to date has not been widely considered and suggests greater research is needed in this area. Collectively, the studies conducted in this thesis contribute to the science base of nanotoxicology, specifically in areas where data are especially lacking and with a focus on bioavailability. These studies have identified that fish hepatocytes do not offer an effective screen for MNPs, and the data produced further suggests that the MNPs tested are not toxic in that form. Working with CARS I have helped advance the understanding on its utility for nanotoxicology studies, with regards to its application and limitation for uptake analyses. The study of MNPs in combination with NOM has identified the fundamental change that real life exposure scenarios may instigate for toxicity assessments of MNPs, with significant impact on risk assessment criteria. Finally, I’ve established that maternal transfer is an exposure route for MNPs that requires further study, with evidence of transfer to sensitive life stages in a non-mammalian system.

Nanotechnology is a diverse area of research that involves the creation of new materials and tools that are able to manipulate and make contact to objects at the nanoscale. One current area of research is into carbon nanotubes, which exhibit unique electrical properties. It is hoped that one-day these nanotubes will be utilised in a variety of applications including use as interconnects in electronic devices. As these new structures have been discovered and microelectronic circuits have decreased in size and increased in complexity, the need for new techniques, capable of fabricating and characterising structures with nanometre precision at specific locations has also increased. One such technique, which is attracting considerable attention, is electron beam induced deposition, because it is a direct-write or maskless procedure with a simple manufacturing process that can be used with a wide variety of materials. However, in order for it to be accepted as a mainstream technique it is necessary to first achieve a high degree of understanding and control of the process.

Simulations of nanoscale systems where fluid mechanics plays an important role are required to help design and understand nano-devices and biological systems. A simulation method which hybridises molecular dynamics (MD) and continuum computational fluid dynamics (CFD) is demonstrated to be able to accurately represent the relevant physical phenomena and be computationally tractable. An MD code has been written to perform MD simulations in systems where the geometry is described by a mesh of unstructured arbitrary polyhedral cells that have been spatially decomposed into irregular portions for parallel processing. The MD code that has been developed may be used for simulations on its own, or may serve as the MD component of a hybrid method. The code has been implemented using OpenFOAM, an open source C++ CFD toolbox (www.openfoam.org) . Two key enabling components are described in detail. 1) Parallel generation of initial configurations of molecules in arbitrary geometries. 2) Calculation of intermolecular pair forces, including between molecules that lie on mesh portions assigned to different, and possibly non-neighbouring processors. To calculate intermolecular forces, the spatial relationship of mesh cells is calculated once at the start of the simulation and only the molecules contained in cells that have part of their surface closer than a cut-off distance are required to interact. Interprocessor force calculations are carried out by creating local copies of molecules from other processors in a layer around the processor in question. The process of creating these copied molecules is described in detail. A case study of flow in a realistic nanoscale mixing channel, where the geometry is drawn and meshed using engineering CAD tools, is simulated to demonstrate the capabilities of the code for complex simulations.

The assembly of mononuclear and polynuclear molecular building blocks has been investigated as a route to extended metal oxide structures. Various [MX[subscript(y)]]ⁿ⁻ (X = Cl, OMe, OH) and [(RO)M'M₅O₁₈]³⁻ (R = MeO, M' = Sn, M = W) building blocks have been synthesised. Controlled hydrolysis has been explored for transition and main group metal hexahalides [MCl₆]ⁿ⁻ M=Ti, Sn using ¹⁷O enriched water. An attempted synthesis of [Me₃NCH₂Ph] [Sn(OMe)₆] gave the dinuclear product [Me₃NCH₂Ph] [Sn₂(OMe)₉]. Variable temperature ¹H NMR studies revealed exchange between terminal and bridging alkoxides and the limiting spectrum is consistent with solid state structure. 2,6-lutidinium hydrochloride was synthesised and used to chlorinate the metal alkoxides {M(OR)[subscript(n)]} (M = Nb). A route to monochloro niobium alkoxide {NbCl(OMe)₄} was developed and variable temperature ¹H NMR spectroscopy studies of {NbCl(OMe)₄} in different solvents revealed exchange between bridging and terminal alkoxides and also suggested the presence of different structural isomers in solution. A novel heterometallic Lindqvist type of POM containing Sn has been successfully synthesised by using controlled hydrolytic aggregation. A mixture of (TBA)₂WO₄, WO(OMe)₄ and {Sn(O[superscript(t)] Bu)₄} was partially hydrolysed in a non-aqueous solvent to give (TBA)₃[(MeO)SnW₅O₁₈] (1). ¹¹⁹Sn NMR INEPT and selective tin decoupled proton NMR experiments have been carried out to determine the axial and equatorial ²J {¹¹⁹Sn*¹⁸³W} coupling constants and to estimate ³J{¹¹⁹Sn¹H} and ³J{¹¹⁷Sn¹H} coupling constants. The electrochemistry of (1) was studied by cyclic voltammetry (CV), and was shown to undergo a reversible one electron reduction close to the solvent limit. Hydrolysis of [(MeO)SnW₅O₁₈]³⁻ produced [(OH)SnW₅O₁₈]³⁻ (2) which is stable in the solid state but in solution undergoes a condensation reaction to give [(µ- O)(SnW₅O₁₈)₂]⁶⁻ (3). The chloro stannotungstate [ClSnW₅O₁₈]³⁻ (4) was also obtained during the synthesis of (1) and (2). Compounds (2) and (4) are crystallographically isostructural and Sn hetero site was disordered over all six metal positions in both anions. The redox properties of (4) were studied by CV and showed an irreversible reduction peak at -1.67 V. Compound (4) is stable in air and did not react with H₂O or PhOH but did react with MeOH or NaOMe to give (1). It also reacted with diisopropylamine (DIPA) to produce the H-bonded aggregate [(Prⁱ₂NH₂)₂(µ-O)(SnW₅O₁₈)₂]⁴⁻. The adduct structure is related to a recently characterised titanium analogue [(µ-O)(TiW₅O₁₈H)₂]⁴⁻ , which forms the H-bonded THF adduct [(µ-O)(TiW₅O₁₈H)₂(THF)]⁴⁻ . 2D-¹H EXSY NMR studies of the mixtures of (1) and MeOH did not show any exchange peaks between (1) and methanol which demonstrates that exchange is slow but reactivity studies of (1) have been carried out with various alcohols and phenols to give substituted products. Sterically smaller alkyl groups gave trans disordered structures, but no disorder is present in structures of anion with bulkier aliphatic alkoxide and aryloxide groups. Hydrogen bonding was observed between the POM cage and pendant phenolic OH groups All the alkyl and aryloxido derivatives have been characterised by single crystal X-Ray diffraction, ¹H and multinuclear NMR spectroscopy, infrared spectroscopy and CHN analysis. Preliminary studies to explore the immobilisation of metal alkoxides [Ti(OPrⁱ )₄] and (1) on ~30% OH functionalised Si(111) surfaces have been carried out. The attempted covalent immobilisation of (1) to Si(111) surfaces appeared to be successful from Atomic Force Microscopy (AFM) measurements.

This Thesis reveals the strategies for the construction and replication of mechanically interlocked molecules, particularly rotaxanes, which consist of a macrocyclic ring that encircles a linear component terminated with bulky groups. The work highlights our recent research activities in exploring the recognition-mediated synthesis of this class of interlocked molecule and its amplification by replication. Our starting point is the minimal model of self-replication. The introductory chapters (Chapter 1 and 2) provide some background and significance to the study, which presents comprehensive review of the published work carried out in the area of self-replication with existing examples from biomimetic and discrete synthetic assemblies. In Chapter 1, we mainly discuss the do and the donʼts in designing successful self-replicating systems based on our own experience in previous work. Our chief concerns in Chapter 2 are the understanding of the chemistry of the mechanical bond and the synthesis of rotaxanes by three means of approaches (clipping, threading and stoppering, and slippage). Attractive and useful examples are illustrated for each mechanism. Moreover, the definition and the roles of templated-synthesis of interlocked molecules are described. Recent advances in the understanding of the nature of the mechanical bond have also been introduced into molecular electronic devices. Emphasis is placed in Chapter 3 upon the essential requirements for the design of self-replicating rotaxanes, namely a recognition site, a reactive site and a binding site. These aspects are explained in the designed minimal model chosen in the past (Replication model 1) and the alternate proposed models (Replication model 2 and Replication model 3). The importance of high association constant to provide substantial amount of pseudorotaxane [L•M] precursors is exemplify in the simple kinetic model of rotaxane formation. The advantages and disadvantages of each independent minimal replication model are also summarized. In the self-replicating rotaxane frameworks, the principal strategy involves a selection of an efficient macrocycle to accommodate the guest unit. Thus, Chapter 4 exclusively describes the design, synthesis and binding properties of a series of macrocycle incorporating the hydrogen bond donors and/or hydrogen bond acceptors motif. In particular, the guests were designed and synthesised based on the mutual interactions with the macrocycle framework and the binding experiments is described in details. An account is provided of the problems faced in the synthetic attempts towards the formation of these macrocycles. The novel macrocycle MEU demonstrated a deficient binding performance with amide and urea compounds, and thus abandoned in later stages. The developed macrocycle MDG and MP have been selected as our workhorse macrocycles, which successfully increase the binding strength in the pseudorotaxanes formation. We have learnt that the association constant, Kₐ can be manipulated by the changing the binding site of the guest or redesign the framework of the macrocycle itself. An exhaustive investigation of the performance of self-replicating rotaxanes focuses on Replication model 1 is demonstrated in Chapter 5. It was evident now that as a consequence of low Kₐ, a substantial amount of thread is present over rotaxane. The implementation of the simple kinetic model of rotaxane formation is prevailed through out this chapter. The position of the central reversible equilibrium in this model effectively resulted in a different reactivity of thread and rotaxane. Therefore, it is concluded that the ratio of rotaxane and thread is sensitive to both the association constant for the [L•M] complex and to the ratio of k[subscript(rotaxane)]/k[subscript(thread)]. The key marker for the efficiency of the rotaxane-forming protocol is the ratio of rotaxane, R to thread, T. In previous chapter, the Kₐ for the [L•M] complex was around 100 M⁻¹ and k[subscript(T)] = 3 k[subscript(R)], which led to an unacceptably small [R]/[T] ratio. We demonstrated for the first time in Chapter 6, that it is possible to manipulate the Kₐ for the [L•M] complex by means of a change in temperature. Yields of a rotaxane can be improved by employing a two-step capture protocol. Cooling a solution of the linear and macrocyclic components required for the rotaxane increases the population of the target pseudorotaxane, which is then captured by a rapid capping reaction between an azide and PPh₃. The resulting iminophosphorane rotaxane can then be manipulated synthetically at elevated temperatures. Following this, these imines could be reduced readily to afford the stable amine rotaxane. Replication model 2 is subsequently proposed as alternate replication framework in Chapter 7, which realised significant advantages over the first model. A number of designs of a potential self-replicating rotaxane have been fabricated in order to integrate self-replication with the formation of rotaxanes. An account is provided of the problems faced with the unanticipated larger cavity of the newly prepared acid recognition macrocycles, and hence, force us to search for a new scaffold of the nitrone structures. Pleasingly, a substantial amount of rotaxane was present, mostly as trans diastereoisomer. It is concluded that the resulting rotaxane structures may be self-replicating through the recognition-mediated pathways from the preliminary kinetic experiments. Nonetheless, the remainder of the full kinetic analysis are prevented given a small quantity of the necessary building block. Chapter 8 reveals our recent efforts to demonstrate the notions behind the final replication scheme, Replication model 3. We have become aware that the reactive site must be placed sufficiently far away from the binding site to inhibit the remote steric effect through the proximity of the macrocyclic component. The design of novel nitrone structures is described in details. We bring together conclusions that can be drawn from three designated replication models in Chapter 9. Experimental and synthetic procedures of the target compounds and appropriate spectroscopic analysis of the products are elaborated in Chapter 10.

A holistic approach to replacing chromium bright plate and the associated wastes from that electroplating industry is taken. The ideas and strategies associated with integrating nanotechology coating production with green chemistries are explored in new horizons for metallic coatings. Thus a literature review of metal coating technology, exploring the best and commonly accepted technology along with new and emerging plating technology is presented. This places emphasis on selection of metal alloy replacements (Mo, Fe, Co, Sn) for Cr and Cr alloys. Selection of final metals for trial in experimental alloys related to their considered contribution towards bright finish and their physical and corrosion properties. Based on the concept of using a large organic delivery molecule to produce nano-metallic plate structures, two ligands were employed, Gluconate (G) and Dithizone (D). Co/Fe and Co/Fe/Sn experimental alloys were produced (using these ligand metal complexes) via four plating technology systems (galvanic batch process, dynamic flow process, sonochemical process and brush sono technique). Electroplate coating thicknesses are reported via calculations employing density, mass and volume considerations. Chemical and structural analysis i.e. (XRD, AAS, SEM, AFM), hardness via the phase tool within the AFM system are reported. Decisions about future work are reported, based on fmdings and progress to date. These findings indicate coating thickness in the range 3.58 IlID to 69.45 urn and relate them to plating conditions and methodology. They also illustrate that nano-coatings are being produced but there is inconsistency of the surface structures i.e. individual nano-particles (of the order 140 nm diameter) are seen, but also conglomerates as large as 4000 nm diameter are observed. Reassessment of the whole research obtainable goals, for this area of advancement, within a 3-year time frame is made. The plating processes and production of test specimens is concluded to be far too labour intensive and a step limiting factor in this research. To this end, a major final conclusion relating to the use of robotics and automation of experimental plating processes is presented as an aid to future research.

This thesis presents the results of several physical and magneto-optical experiments using nanostructured silicon fabricated by an electrochemical etching method. Quantum confinement causes the efficient visible light emission of nanocrystalline silicon. Long lived excitons confined in silicon nanocrystals are applied as an energy storage medium for energy transfer to oxygen. Nanocrystalline silicon-silica aerogel composites are synthesised and examined the sensitivity with adsorbed oxygen molecules. Efficient energy transfer from photo-excited excitons to molecular oxygen to create singlet oxygen is presented in the experimental results. Spin exchange interactions are a key aspect controlling the energy transfer between silicon nanoparticles and molecular oxygens. Hence, modifications of the spins alter the dynamics of the energy transfer process. Spin distributions of the participating states are changed by applying magnetic fields or by changing excitation powers. Therefore, the dependences of the transfer process on magnetic field, excitation power and oxygen concentration were studied. The energy transfer model is constructed based on a rate equation approach. The model produces simulations that are in good agreement with the overall data. The dynamic parameters are provided and indicate the characteristics of the silicon nanostructures. Possibilities for future work in this research area are included.