For more than a decade nanomaterials have attained huge attraction owing to the exceptionally different and excellent characteristics as compared to their bulk form. In the present research, we focus on understanding the properties and performance of nanocomposites in solid and liquid states. There are three major areas involved in this thesis research. Firstly, we will identify effective methods or techniques to evaluate nanomaterials. Conventional and non-conventional techniques will be implied. The second part is to study the interfacial reactions between nanoparticles (NPs) and fluid molecules. This is to obtain basic understanding of nanoparticles and their interactions with matrix materials. Thirdly, we will investigate the mechanical properties of nanocomposites. Experimental results showed that the mechanical properties of nanocomposites measured at macroscale exhibited differences when the shape and size of gold NPs were changed. The morphological characteristics of the material were shown effectively at the nanoscale based on the NPs' shape and size. The properties of NPs influenced the properties of gold colloid. Such changes were the result of the interfacial interaction of gold NPs and the host material.

The analytical utility of gold nanoparticles (AuNPs) for laser desorption/ionization mass spectrometry (LDI-MS) is examined here. An evaluation of the parameters that affect desorption/ionization show that careful treatments of AuNPs is needed, as subtle changes in the solution environment can result in subsequent changes in the mass spectra. A thorough evaluation of the parameters that affect desorption/ionization of peptides is presented here, and these parameters include: (i) AuNP-to-analyte ratio, (ii) AuNP size, (iii) solvent, (iv) AuNP surface composition, (v) pH and buffer effects, (vi) amino acid sequence, and (vii) additives such as fructose or glycerol. Specifically, controlling the AuNP-to-analyte ratio, pH, peptide composition, and AuNP size are important parameters for ionization. Additionally, effects of passivating the AuNP surface with halides or oxyanions was investigated. The presence of NaF, NaCl, NaBr, and NH4X (X = F, Cl, Br, I) were shown to not significantly affect analyte ion abundances, whereas addition of NaI strongly suppressed analyte ion yields. Further physical characterization of the NPs showed that etching had occurred, which suggests that the surface chemistry of the NPs is important for desorption/ionization. Throughout these investigations, questions remain as to what the internal energies of peptides are after the desorption/ionization event, and how energy is deposited. Peptide ion fragmentation is examined under different solution conditions to evaluate the relative internal energies of peptides, and the fragmentation pattern examined for insight into fragmentation mechanisms. The data suggest that radical species are important for fragmentation of peptides when using AuNPs. However, it is likely that multiple processes are actually directing the fragmentation. Finally, based on the data presented in this dissertation, a thermal desorption mechanism of pre-formed ions is proposed. This fundamental research is intended to lay foundations for optimizing the use of nanoparticles in routine LDI-MS analysis as well as giving insight into nanoparticle ionization mechanisms. Since very little work has been done in this area, this dissertation investigates, in detail, many of the subtle characteristics that affect desorption/ionization of biomolecules when using NPs.

The synthesis of solid state materials has traditionally been accomplished using rigorous heating treatments at high temperatures (1,000°C) to overcome the slow rate of diffusion between two reactants. Re-grinding and re-heating treatments improve the rate of reaction between two solids; however, the high temperatures required to overcome the diffusion barrier limit the products accessible to the most thermodynamically stable phases. In this work, nano-scale solids such as alloys and intermetallics were synthesized via solution techniques where metal compounds are reduced by NaBH4 or n-butyllithium at temperatures below 300°C. To form hollow particles, metal nanoparticles of Co, Ni, Pb were synthesized via reduction by NaBH4 in water and reacted with K2PtCl6, which resulted in the formation of alloys in the case of Co-Pt and Ni-Pt. PbPt intermetallic hollow particles were synthesized by heating a composite of PbO and hollow Pt nanoparticles in tetraethylene glycol (TEG) at 140 °C. With n-butyllithium as a reducing agent, Au3M (M= Fe, Co, Ni) nanoparticles could be synthesized as isolatable solids in the L12 structure. PtSn and AuCu3 intermetallics were synthesized using NaBH4 and TEG. The PtSn and AuCu3 nanoparticles were characterized by transmission electron microscopy in attempts to learn about the phase diagrams of nanoscale solids. The purpose of this work was to synthesize nanoparticles via solution-mediated routes at low temperatures in compositions and morphologies not observed in the bulk, and learn about the phase diagrams of nanoparticles to understand why it is possible to access solids at temperatures significantly below those used in traditional solid state chemistry.

Composite propellants are composed of a solid oxidizer that is mixed into a hydrocarbon binder that when polymerized results in a solid mass capable of self-sustained combustion after ignition. Plateau propellants exhibit burning rate curves that do not follow the typical linear relationship between burning rate and pressure when plotted on a log-log scale, and because of this deviation their burning behavior is classified as anomalous burning. It is not unusual for solid-particle additives to be added to propellants in order to enhance burning rate or other properties. However, the effect of nano-size solid additives in these propellants is not fully understood or agreed upon within the research community. The current project set out to explore what possible variables were creating this result and to explore new additives. This thesis contains a literature review chronicling the last half-century of research to better understand the mechanisms that govern anomalous burning and to shed light on current research into plateau and related propellants. In addition to the review, a series of experiments investigating the use of nanoscale TiO2-based additives in AP-HTPB composite propellants was performed. The baseline propellant consisted of either 70% or 80% monomodal AP (223 μm) and 30% or 20% binder composed of IPDI-cured HTPB with Tepanol. Propellants’ burning rates were tested using a strand bomb between 500 and 2500 psi (34.0-170.1 atm). Analysis of the burning rate data shows that the crystal phase and synthesis method of the TiO2 additive are influential to plateau tailoring and to the apparent effectiveness of the additive in altering the burning rate of the composite propellant. Some of the discrepancy in the literature regarding the effectiveness of TiO2 as a tailoring additive may be due to differences in how the additive was produced. Doping the TiO2 with small amounts of metallic elements (Al, Fe, or Gd) showed additional effects on the burning rate that depend on the doping material and the amount of the dopant.

The interaction of laser radiation with a material can excite coherent lattice vibration. The observation of such periodic motion of the atoms in the lattice provides information on the properties of the material. In the present work a femtosecond pump-probe technique was applied for studies of acoustic vibrations in nanoparticles and nanowires, and coherent optical phonons in thin films. The elastic properties of spherical Ag nanoparticles and Ag and Bi nanowires were studied in a dual-color femtosecond pump-probe experiment. The results of the period determinations of the acoustic vibrations, obtained from the time-domain measurements with low intensity pump pulses, together with the information about the size of the particles, were used to determine the elastic constants of the materials. Also changes in the measured acoustical response of the Ag nanowires under high intensity laser excitation were studied. In addition the coherent optical phonon excitation in a Bi film was studied in a femtosecond pump-probe experiment. A red-shift of the phonon frequency at the high photoexcitation density was observed. To separate the effect of the lattice softening and the lattice anharmonicity the excitation with two pump pulses was employed. Numerical simulations, which took into account the evolution of the spatial inhomogeneity of the excitation density, were carried out and compared to the experimental results.

Water-soluble fluorescent probes with emission in the 600-800 nm region have significant potential in biological applications such as cell imaging. Most fluorescent probes however suffer from limited fluorescence brightness in aqueous media due to aggregation and self-quenching. Their photostability in animal models for an extended period of time is also a concern. One way of improving their photophysical properties is to encapsulate them in a protective matrix to form fluorescent nanoparticles. We have synthesized a set of six through-bond energy transfer cassettes which emit in the 600-800 nm region with Fluorescein or BODIPY as donor and benzophenoxazine dye Nile Red or cyanine dye Cy5 as acceptor. Their photophysical properties in organic and aqueous media were evaluated. Some of these cassettes were encapsulated in silica or calcium phosphate nanoparticles (20 nm in diameter) to improve their solubility and photophysical properties in aqueous media. We also synthesized some water-soluble benzophenoxazine based fluorophores and the impact of different water-soluble groups on their emission characteristics in aqueous media was studied. Selected fluorophores were used for in vitro cellular imaging studies.

In this work a plasma torch system has been setup. Using the methane as gas source, carbon atoms were ionized and diamond nanoparticles were synthesized. Argon or nitrogen gas was applied as carrying gas for dilution methane. By means of Field-emission scanning electron microscopy (FE-SEM), X-ray Diffraction (XRD), Raman Scattering, Transmission Electron Microscopy (TEM) and Transmission Electron Diffraction (TED) diamond nanoparticles were characterized. The system is characteristic structured with a MP system interior with an antenna. The microwave was guided in chamber and to the antenna tip, and induced the microwave energy gather on the tip then induces plasma under higher pressure. Expect sample N01 that used nitrogen carrying gas and gas flow rate was 0.6 L/min, the particles all have the size between 25-50nm from the analysis of the morphology of the particles by SEM. The particles size increased along with the carrying gas flow rate as well as the pressure increased. The materials structure has been analyzed by Raman, XRD. The natural diamond structure has been found synthesizing the nanoparticles under the high pressure or the higher catalyst gas flow rate. And as carrying gas effect, nitrogen is better than Argon. The electron beam energy would destroy the structure of diamond nanoparticles during TEM analysis and diamond nanoparticles changed from single crystal to amorphous has been observed by TED analysis.

The study of this project includes nomenclature, methodologies for risk assessment, and the exchange of information on human and ecological toxicology studies in nanotechnology research. The goals are: (1) collecting domestic and international nanotechnology relevant to toxicity information, (2) establishing the flow chart of nanotechnology risk assessment, (3) making suggestions of methodologies for risk assessment on nanotechnology, and (4) establishing the structure of nanoparticles risk management for reference to future nanotechnology risk management. Nanopartilces, quantum dots, fullerenes and carbon nanotubes has been collected in Toxicological information of nanomaterials. This study has established the Precautionary Principle and the preliminary framework for health risk assessment, which could prevent or reduce risks before the completed development of the potential danger, and reply the appeal for developing a standard methodology for risk assessment which is made by European Commission during the Brussels Conference of 2004. Exchange of informations of nanotoxicology allows contact between domestic and international researchers. The methodologies for risk assessment establishes framework for health assessment of risks which could be used to be the direction to develop the internal risks assessment, and is advantageous to the government in management of the risks of nanotechnology.

We prepare a series of gold-silver alloy nanoparticles with different Au/Ag mole ratio. The UV/Vis absorption spectra of nanoparticle solutions exhibited one surface plasmon resonance absorption band and the surface plasmon absorption band of the gold-silver alloy nanoparticles is blue-shifted with increase the Ag content. Finally, we produced the nanoparticles capping with alkanethiolate and alkanecarboxylate via place-exchange reaction. The nanoparticles have been characterized by ICP-MS, TEM, 13C-NMR, FT-IR, UV-Vis absorption spectroscopy. We suggest that the carboxylate group is coordinated to the Ag ion as a bridging bidentate.

Abstract This research is focused on the condensation and phase transformation of NiO-TiO2, Co1-XO-NiO, and Co1-XO-MgO solid solution via dynamic laser ablation condensation and high temperature annealing. TiO2 rutile nanospheres with enhanced solid solution of NiO were synthesized via very energetic pulse laser ablation on clamped Ni/Ti target in oxygen for a very rapid heating/cooling, and hence pressure effect. Upon electron irradiation, the NiO-dissolved rutile (r) were partially transformed into 2(01 ) commensurate superstructure and Ni2(1+x)Ti1-xO4 spinel (s) following the crystallographic relationship [111]r//[012]s; (10 )r//(200)s. Alternatively, random NiTiO3 nanodomains were formed from amorphous regions in such a rapid decomposition process. In addition, the dense fluorite-type (f) derived TiO2 condensates dissolved up to 5 at% Ni2+ of the cations were synthesized via the same route. The nanocondensates less than 20 nm in size are nearly cubo-octahedral in shape and tended to transform martensitically to monoclinic (m) baddeleyite-type following the crystallographic relationship (100)f//(110)m; [001]f//[001]m. The condensates twice larger in size, with considerable matrix constraint, are nearly spherical in shape and consist of mosaic m-twin variants following complicated crystallographic relationships with each other and with the relic f-phase: (010)f//( 20)m; [001]f//[001]m. The charge and volume compensating oxygen vacancies due to NiO dissolution in the dense TiO2 condensates could facilitate the relaxation and amorphization process. Further more, pulse laser irradiation of Ni, Co, and Co-Ni (or Ni-Co) targets in an oxygen background gas produced nanocondensates with rock-salt type structure. Analytical electron microscopic observations indicated that such nanocrystals are cubic in shape for NiO and cubo-octahedral for Co1-xO and Ni1-xCoxO. The nanocrystals coalesced predominantly with {100} or {111} facets to form nano chain aggregates or closer packed manner. The Co1-xO was more or less oxidized as Co3-