Industrially viable blends having microstructures that can be converted into a nanostructured material by post chemical treatments, potentially should have a commercially viable solution to the development of nanostructured materials for practical applications. In this regard a polypropylene-boron oxide (PPBO) blend provides a model study here. In this paper we wish to report the synthesis of PPBO blends with different concentrations of boron oxide by melt grafting and through reactive extrusion. The tensile strengths of the ideal blend has been found to be 62% higher than polypropylene (PP). By chemically treating the blends for a period of 24 hours to 72 hours the tensile strength of the blends increased by 152%. The blends have been characterized by fourier transform infra red spectroscopy (FTIR) and scanning electron microscopy (SEM). An interesting characteristic of the PPBO blend has been the development of surface potential that changes upon visible light excitation. The increased tensile strength has been attributed to the conversion of micro structured blends to nanostructured blends. The improvement in thermal stability can be attributed to a good PP matrix-oxide interaction and also due to the thermal conductivity of the boron oxide. The good dispersion of the nanotubes in the polymer matrix allows the spreading of heat uniformly along the fiber.

Chemical Vapor Synthesis (CVS) is the conversion of molecular species into nanocrystalline particles by chemical reactions in a gas flow reactor. Pure anatase nanoparticles are generated in a hot wall reactor from titanium isopropoxide using different time-temperature-profiles. The time-temperature-profile (T(t)-profile) in the gas phase of the reactor has a profound influence on the particle characteristics such as particle microstructure and surface chemistry and, therefore, on the quality of the powder consisting of nanocrystalline particles. In this study a simple reaction-coagulation-sintering model (CVSSIN) was used to predict influence of the T(t)-profile on the powder characteristics. The as-synthesized anatase powders show a very high degree of crystallinity, primary particle of about 10 nm sizes and a low degree of agglomeration.

A new post-synthesis heat/ligand-exchange treatment on CdSe nanocrystal quantum dots that allows fine-tuning the quantum dots size without losing important properties (e.g. photoluminescence) is presented. The careful control of parameters such as the reaction temperature, the quantum dot to alkyl-amine ligand mole ratio and the solvent volume is shown to provide tunable size reduction of the nanocrystals. This size reduction phenomenon provides new insights into the surface chemistry and stability of nanocrystals and can serve as a platform for designing, controlling and processing nanomaterials with tailored properties.

The nature of the dispersion of a clay platelet in a resin composite will play an important role in the process of enhancement of the physical properties of that material. This paper describes studies of ultrasonically and mechanically mixed dispersion of various clays in methyl methacrylate (MMA) and reports the effects of organic surface modification on the rheology, suppression of settlement of filled systems, cure characteristics and final mechanical properties.

Colloidal crystal templating has been used to prepare three-dimensionally ordered macroporous (3DOM) films of La1-xSrxMnO3-d (LSM), yttria stabilized zirconia (YSZ) and porous composites of LSM and YSZ. These materials have direct applications as cathodes in solid oxide fuel cells (SOFCs). The 3DOM materials have been prepared by low temperature processing, which is a major step towards overcoming electrode sintering, interdiffusion and deleterious phase formation associated with conventional high temperature processing. The preparation of porous composites and the elimination of high temperature densification presents an opportunity to create SOFCs with a large number of triple phase boundaries which should be accompanied by an corresponding improvement in device performance. The microstructure of the 3DOM films was assessed using scanning electron microscopy and the crystal structure and phase purity assessed by x-ray diffraction.

Nanostructured materials and nanocomposites have inspired many structural and functional applications in recent time. In the last decade, energy-storage devices have employed electrode materials in form of nanomaterials/nanocomposites to yield promising electrochemical performance. The current paper throws light on the application of nanostructured pristine activated carbons as well as chemically modified carbon-halide nanocomposites in practical electrochemical supercapacitors. Pristine activated carbons have been mechanochemically modified via high-energy milling and iodine doping to produce carbon-halide nanocomposites. A significant change in existing physical and electrochemical properties has been marked by introduction of iodine into carbon and the subsequent formation of nanocomposites. The effect of halides and nanoscale morphology is discussed using X-ray, Raman spectroscopy, DSC, BET analysis and electrochemical testing.

We report on a fundamental morphology growth of gold-based nanoparticles by solution radiolysis. Radiolysis of pure gold-polymer solutions of different dose rates and aging time is examined. A detailed description will be presented of the experimentation, testing and analysis. In particular, we will present data on the formation of gold nano-octahedra and -prism particles. The γ-irradiations were carried out with a 60Co source of 1.345 × 105 Ci (Sandia National Laboratories Gamma Irradiation Facility (GIF). Nanoparticle characterization techniques included are UV-vis and TEM. Similar to what has been seen in earlier silver nanoparticle studies, dose rate dictates the size of nanoparticles formed. At high dose rate, all reducing species are produced and scavenged within a short time, and then coalesce into separate nanoparticles. At low dose rate, the coalescence process is faster than the production rate of the reducing radicals. The reduction of radicals occurs mainly on clusters already formed. The differences in the morphologies result from a combination of dose rate, aging and lack of radical scavengers (e.g. isopropyl alcohol), resulting in either gold nano-spheres, octahedral or prism nanoparticles. The progressive evolution with dose rate of the UV-visible absorption spectra of radiation-induced metal clusters is discussed.

The aim of this work was to synthesise nanopowders by laser pyrolysis in order to elaborate Si3N4-SiC nanocomposites exhibiting a high ductility at high temperature. The synthesis of SiCN and SiCNYAlO nanopowders with a good thermal stability has been developed from a liquid mixture based on hexamethyldisilazane with a gaseous precursor (silane, SiH4) and ammonia. Si3N4-SiC nanocomposites exhibiting almost theoretical density have been elaborated by hot pressing under 35 MPa at 1600°C either from SiCNYAlO nanopowders or from SiCN nanopowders mixed with commercial sintering aids nanopowders (6 wt% yttria and 3 wt% alumina) in ethanol and de-agglomerated by milling with Si3N4 balls. The densification behaviour is better for nanopowders containing in-situ additives. In addition, using prealloyed powders enables to simplify the elaboration process since the mixing step of the nanopowders is eliminated. The nanocomposites elaborated from the mixture (SiCN + commercial sintering aids) exhibit a different microstructure, depending on the drying process (under vacuum or in an oven) of the nanopowders after the mixing step: When drying was performed in a confined atmosphere, a noticeable amount of Si2N2O was detected in addition to β-Si3N4 and the average grain size was 60 nm, whereas the crystalline phases were α- and β-Si3N4, when the slurry was dried under vacuum and the average grain size was 200 nm. The creep behaviour of the two grades was assessed under compressive loading in air and the deformation appears strongly influenced by this change of the microstructure: A strong ductility was observed for the smallest grain size: a deformation as high as 45 % was measured under a compressive load of 180 MPa at 1350°C under air.

In this study a group of resorcinol-formaldehyde carbon cryogels (CC) have been processed chemically, via catalysis and activation, to obtain varied nanostructures and pore size distributions. To understand the relation between structure and electrochemical properties the capacitor can be studied as a dielectric system composed of a porous electrode and the electrolyte (Tetraethylammonium tetrafluoroborate in propylene carbonate). Using Electrochemical impedance spectroscopy (EIS) the complex capacitance and power are used to study the behavior of the system below the relaxation frequency fo (φ = −45°). Therefore, the relaxation of the capacitor system at the low frequency range, f < fo, may be used as a measure of pore/electrolyte interaction. The approach here proposed also allows for a direct experimental characterization of the capacitance and power at low frequencies where small pores are likely to affect the diffusion dynamics of the electrolyte molecules. The results suggest a correlation between the occurrence of small micropores and that of high power losses that are related to the resistive element produced at the low frequency range. Moreover, the impact of the micropore structure upon the supercapacitor's performance is apparent in its capacitance and energy as well. In addition to the complex power and capacitance other measurements including BET Nitrogen sorption, cyclic voltammetry, galvanic cycling and X-Ray Raman Scattering were used to characterize the samples and support these results.

The effects of surface treatment, particle size, and concentration of titanium dioxide (TiO2) and its dispersion on the photodegradation of two resin systems, epoxy and acrylic urethane, were examined. A suite of techniques, including laser scanning confocal microscopy (LSCM) and attenuated total reflectance -Fourier transform infrared spectroscopy (ATR-FTIR), was used to follow the degradation process of TiO2/polymer films as a function UV exposure. LSCM was used to show that both pigment dispersion and durability of the polymer matrix influenced the generation of pits/holes in pigmented polymer film. The type of pigment had a greater influence on the more durable polymer matrix, the acrylic urethane system. The epoxy system showed the greatest extent of degradation regardless of the TiO2 choice. The LCSM results were supported by the ATR-FTIR data.

We investigated electric and chemical properties of metal/Y2O3 interfaces. The Pt/Y2O3 interface can be chemically activated by bias voltage, resulting in a microscopic oxidation-reduction center at interface. The oxidation-reduction of the center alternatively changed resistance of the Pt/Y2O3 system, and the alternation yield hysteresis with respect to the bias voltage, i.e. a memory effect. On the other hand, in Au/Y2O3 system, non-oxidization of Au induced ejection of O2 gas from the interface, so that there was no memory effect. Possible reactions of these metal/Y2O3 systems were proposed, and the balance between oxidation and reduction at microscopic center was concluded to be essential for the memory effect.

A new method of fabricating nanocomposite films made up of multiwall carbon nanotube and nanocrystalline copper was developed by using an electrochemical deposition. The electroplated CNT/Cu nanocomposites have the microstructure that CNTs are well dispersed in both the planar and depth directions without any voids in the matrix. The conditions were successfully achieved by using some amphiphilic polymers, organic additives and a pulse electrodeposition method. The microstructure and CNT composition of nanocomposite films were strongly affected by the concentration of CNT in the electrolyte. The mechanical and electrical properties of CNT/Cu nanocomposite films were investigated with the variation of CNT content in the nanocomposite films.

We propose the new process for fabricating Al-rich Al2O3 thin film, which is used as a charge storage layer for non-volatile Al2O3 memory. Nanoscale Al-rich thin film is deposited using RF magnetron co-sputtering by setting an Al metal plate on an Al2O3 target. Al-rich Al2O3 shows a larger conduction current in I-V characteristics and larger optical absorption than stoichiometric Al2O3 due to the increased electron trap sites. The C-V characteristics of the Al-rich Al2O3 thin film show a large hysteresis window due to the charge trapping effect in the Al-rich structure.

Sintering of silicon nanoparticle chain aggregates composed of unequal sized primary particles are investigated using molecular dynamics (MD) simulations at 1500 K. We consider straight chain aggregates consisting of up to 40 2.5 and 5.4 nm primary particles. The sintering time increases with increase in the total volume of the chain aggregate or with increase in the exposed initial surface area of the chain. A mathematical model was developed to describe the dynamics of sintering of such chain aggregates. The model is a power law modification of the Frenkel sintering equation with the Koch-Friedlander model to include primary particle size dependence. We found that the particle size effect is a local process, and important only at the initial stage of the sintering. Thus, the effect is not significant when the aggregate becomes large. The model is amenable for use in aerosol models that might include sintering effects.

Nanoparticles that fluoresce or absorb light in the visible and near-IR wavelengths are desirable for a variety of applications including biological tagging for medical imaging purposes and for solar control glazing in the automobile industry. Semiconductor quantum dots are commercially available and dyed polymer nanoparticles as well as organic dye/silica core shell nanoparticles have also been demonstrated. We report the synthesis, characterization, and optical properties of another luminescent nanoparticle: doped zirconia. The zirconia nanoparticles reported in this study are doped with up to 10% of the lanthanide dopants Er, Gd, Nd and Eu. These materials emit in the visible and near-IR wavelengths depending on the dopant and are refractory, making them useful for high temperature applications. These cations were found to stabilize the cubic phase over the monoclinic phase of zirconia, at approximately 10% dopant, as characterized by X-ray diffraction. We report the luminescence spectra of these nanoparticles at various wavelengths which reveal emissions from the matrix as well as from the dopants.

Polycrystalline Y2O3 is the material of choice for IR windows since it has excellent optical properties in the visible, and near infra-red band. However, current processing methods yield polycrystalline Y2O3 with large grain size (> 100 μm), which limits the hardness and erosion resistance attainable. One way to improve strength is to develop an ultra-fine grained material with acceptable optical transmission properties. To realize a fine-grained ceramic, one approach is to develop a composite structure, in which one phase inhibits the growth of the other phase during processing. In this study, Y2O3-MgO nanocomposite with various MgO content (20, 50 and 80 mol%) were synthesized using plasma spray method. Extensive characterization techniques including x-ray diffraction, scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and Energy Dispersive spectrometry (EDS) were employed to study the synthesized powder as well as the consolidated sample. Transmission Electron Microscopy, as well as EDS chemical mapping, revealed that the consolidated sample have bi-continuous MgO-Y2O3 nanostructure with an average grain size of 200 nm.

The electrical resistivities of nanostructured films of indium tin oxide were measured. The films were prepared using glancing angle deposition, a physical vapour deposition technique. This technique was used to prepare nanostructured indium tin oxide thin films of various morphologies. Films consisting of vertical posts were electrically characterized using a probing station. Compared to a normally evaporated planar film, the nanostructured films were found to exhibit resistivities approximately two orders of magnitude greater. Development of the measurement technique is ongoing, and several ideas for improvement are described.

Citrate-capped gold nanoparticles with narrow diameter distribution were prepared by the reduction of chloroauric acid with borohydride. After the gold nanoparticles were transferred to toluene solution through ligand conformation change, close-packed two-dimensional nanocrystal lattices were obtained on transmission electron microscopy (TEM) copper grids by evaporating approximately 10 μL of concentrated particle dispersion. The formation of the thiolate gold nanoparticles was investigated by UV-visible absorption spectroscopy and FTIR spectra. The 2D Fourier transform power spectra of the monolayer confirmed the supperlattices' hexagonal symmetry. Furthermore, long-range-ordered bilayer superlattices, of which the nanoparticles in the top layer piled on the ones in the bottom layer, could also be observed by transmission electron microscopy.

Synthesis of surface passivated Zr-Al mixed metal-hydride nanoparticles was accomplished via a multi-step process. The initial reaction to produce the zirconium aluminum hydride was via decomposition of zirconium tetrahydroaluminate (Zr(AlH4)4) while exposed to ultrasound produced by a benchtop ultrasonic bath. The particles were surface passivated using carbohydrates and were shown to be stable in air and partially stable in water. TEM imaging suggests the existence of smaller particles made of a Zr-Al alloy that range in size from 1.8 nm to 7.9 nm in diameter and are interspersed with larger particles that range from tens to hundreds of nanometers in diameter. It was also shown that the carbohydrate-derived coating of the nanoparticles is present as an aluminum alkoxide gel surrounding the core particles.

A reduced layered tungstic acid with a double-octahedral structure was prepared by acid treatment of an Aurivillius-type Bi2W2O9 in the presence of Sn2+ ions. While the color of the product formed by acid treatment with no Sn2+ ions present, H2W2O7, was yellow, a blue powder was obtained after the acid treatment in the presence of Sn2+ ions. No notable change in the morphology was observed after acid treatment. The X-ray diffraction pattern of the product acid-treated in the presence of Sn2+ ions was very similar to that of H2W2O7. Essentially all the Bi3+ ions were lost upon acid treatment, indicating the occurrence of selective leaching of bismuth oxide sheets in Bi2W2O9. A UV-visible absorption spectrum and XPS analysis demonstrated that the W6+ ions were partially reduced to W5+ ions, and the number of protons in the product was correspondingly 2.4 per [W2O7]. These results suggest the successful formation of a reduced layered tungstic acid, H2.4W2O7.