In this paper, new synthetic routes have been investigated for the preparation of Organic/inorganic nanocomposite polymer membranes consisting of SiO2 /PTMO(polytetramethylene oxide) hybrids and novel proton conducting materials. These materials have been synthesized through sol-gel processes in flexible, ductile, free-standing thin membrane form. The hybrid membrane has been found to be thermally stable up to 160 C and possesses proton conductivities of approximately 10−4 S/cm from a room temperature to 160 C.

Recently, there has been much interest in creating new layered transition metal oxides. Vanadium oxides may be used as sorbents, catalysts, and cathodes in lithium batteries. The modified sol-gel technique allows for some control towards the final structure of the compound. Using this technique, a new layered vanadium oxide compound - I, containing the surfactant dodecylphosphate, has been synthesized. After the removal of the organic ligand a new compound - II is formed which might be hexagonal. The compounds were analyzed using XRD, TGA, SEM, and NMR. VO2PO3(OH)C12H25(H2O)n is the general formula of the layered product I with a layer spacing of about 40 angstroms. II appears to be hexagonal with a = 43Å. The synthesis, composition, and structure of these compounds are discussed.

Diamine vanadium oxide nanotubes (DA-VOx-NTs) have been prepared in high yields applying two different synthesis routes, namely either a sol-gel reaction followed by a hydrothermal treatment or an exchange reaction. The first route is analogous to the well-known preparation of VOx-NTs containing monoamines: a vanadium(V) alkoxide is mixed with an α, ω- diamine (H2N[CH2]nNH2 with 12≤n≤20), the resulting adduct is hydrolyzed, and, after aging, a hydrothermal treatment leads to the nanotubes in pure form. The exchange of the monoamine template in VOx-NTs against diamines represents an alternative access to DA-VOx-NTs. This reaction occurs readily and is also applicable for diamines with short CH 2 chains like, e.g., in ethylene diamine. The TEM characterization of the DA-VOx-NTs confirms the tubular morphology which is widely preserved in the products of the exchange reactions. The characteristic feature of as-synthesized DA-VOx-NTs is a thick tube wall with many VO, layers while the exchange products are tubes comprising thin walls or bent packs of layers.

Poly(methyl methacrylate) (PMMA) based orthopaedic bone cements contain 1-3 Pim size radiopacifier particles. Incomplete dispersion of these particles leads to the presence of 50-200 μm size agglomerates. These large defects are sites of high-stress concentration that reduce the fracture toughness of PMMA. In this study, the micrometer-sized radiopacifying particles of a commercial bone cement were replaced by nanosized fillers. Both, commercial and nanocomposite PMMA bone cements were characterized using ultra-small angle x-ray scattering and low voltage scanning electron microscopy; mechanical properties were evaluated using ASTM standard tensile testing. The results showed a substantial reduction of particle agglomerate size and a significant increase in tensile properties of the nanocomposite over that of the standard microcomposite bone cement.

We have investigated the photophysical properties of surface capped CdS and CdS:Mn nanoparticles in the form of spin coated thin films of the pure nanoparticles and nanoparticle -polymer blends. The organic capping reagent was p-thiocresol. Electroluminescence (EL) devices were fabricated and characterized by their current/voltage characteristics and EL emission performance. This is to our knowledge the first report on Mn doped CdS nanoparticles applied in EL devices with a single layer device structure (ITO/CdS:Mn/Al). Photoluminescence (PL) and PL excitation measurements were performed on CdS:Mn nanoparticles in pyridine dispersion and on thin films. The PL excitation spectrum shows a narrow peak at 390nm. Excitation at this wavelength yields a broad PL spectrum spanning from about 450 to 700nm, which is dominated by a strong emission band at 585nm. This emission is attributed to transitions involving Mn levels in previous works. The EL emission peak is shifted to the red compared to the PL emission spectra. The characteristics and performance of these new types of EL devices will be presented and discussed.

Sol - gel technology is used to prepare sub-micron to micron size particles of Chromium (IV) doped materials. These materials show strong luminescence, as single crystals, in the 1-2 μm range. Such materials include; Cr (IV): (Ca2GeO4, Mg2SiO4, LiScGeO4). The optically active particles are dispersed into glassy matrixes to form optical composites. Ongoing research is aimed at, a) reducing the size and the size distribution of the optically active particles, and b) finding suitable matrix materials.

We report the synthesis of a nanocomposite materials consisting of gallium nitride (GaN) confined in the well ordered mesoporous transparent matrix MCM-41 with the help of the metalorganic single source precursor triazido(trimethylamine)gallium using solution impregnation technique. The loading of the pores of MCM-41 with GaN was confirmed by chemical analysis, XRD, TEM, BET, NMR and optical spectroscopy (PL and PL-excitation spectroscopy). The composites exhibit a blue shift of the bandgap of GaN due to quantum confinement.

We synthesized the highly ordered mesoporous thin films with alkyltrimethyl-ammonium (CnTMA+). The arrangement of mesopores was depend on the Si/surfactant ratio. The hexagonal(P6mm) arrangement was observed, when Surfactant/Si ratio was 1/10. Increasing the Surfactant/Si ratio to 1.6/10, the cubic (Pm3n) arrangements were observed. A steel vessel for the measurement of the nitrogen adsorption isotherms of thin film on the substrate was designed. It was found that mesopore arrangements in the film is more regular than that in the powder samples prepared by the same acidic synthesis conditions.

The mesostructured vanadia/surfactant composites are synthesized by self assembled processes and phase transition has been investigated. The lamellar mesostructure of the vanadia/surfactant has been shifted to monoclinic and hexagonal mesophase by low temperature annealing, possibly due to the change of the inorganic/surfactant ratio.

Thermally stable alumina and zirconia pillared clays loaded with copper and cobalt cations and silver nanoparticles were synthesized. The structural and surface features of these nanosystems were studied and compared with those of bulk analogs -partially stabilized zirconias and γ-alumina loaded with the same active components. Specificity of the catalytic properties of nanocomposites in the reactions of nitrogen oxides reduction by propane, propylene and decane in the excess of oxygen appears to be determined both by the degree of interaction between pillars and active components and the type of reducing agent.

Room-temperature synthesis of transition metal ( TM = Co, Ni and Mn ) oxide intercalated clays has been developed, which extends the potentiality of clay based materials for the design of electroactive nanophase. The structure was examined by using powder XRD - one-dimensional Fourier analysis, magnetic susceptibility measurement as well as conventional analytical methods. From the results, it was revealed that the oxidation by using NaClO as the oxidative reagent affords a new expanded layer structure with a basal spacing of about 1.96 nm wherein a conductive TM oxide sheetadjacent to two hydrated sodium ion layers resides in the gallery of the clay. The resultant sodium cobaltate interlayered smectite bears multi-functionality; an apparent bulk conductivity in the order of 10−5 Scm−1 and a cation exchange ability.

The catalytic activity of polycrystalline and nanocrystalline CeO2-supported Pd (Pd/pCeO2 and Pd/nCeO2) has been determined as a function of temperature and Pd loading. While the untreated nCeO2 support gives 50% methane conversion at 420°C, the untreated pCeO2 support exhibits little activity under the conditions examined due to its low surface area. A Pd loading of 5 wt% increases the activity of pCeO2 to 50% conversion at 260°C, while a 40 wt% Pd loading on nCeO2 exhibits a relatively smaller activity increase, yielding 50% conversion at 240°C. On a mass basis the 40 wt% Pd/nCeO2 catalyst is the most active tested in this study, but it is less active than the 5 wt% Pd/pCeO2 catalyst on a surface-area basis. Furthermore, the activity of the 40 wt% Pd/nCeO2 catalyst does not decrease during 100 hrs of exposure to CH4 and O2 at 250°C.

X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) have been used to characterize the surfaces of both bare supports and Pd-containing catalysts before and after exposure to reactor conditions. The XPS results reveal that the Pd surface concentration is more than an order of magnitude higher for 5 wt% Pd/pCeO2 than for 5 wt% Pd/nCeO2 due to the larger surface area of nCeO2 and that the 40 wt% Pd/nCeO2 catalyst has a lower Pd loading on a surface-area basis than the 5 wt% Pd/pCeO2 catalyst. Most of the supported Pd is in the form of PdO, but higher PdO2/PdO ratios are observed for both CeO2 supports compared to Pd supported on ZrO2 or CO3O4. Furthermore, a significant amount of metallic Pd forms on Pd/nCeO2 but not on Pd/pCeO2 during reaction. The nanocrystalline and polycrystalline CeO2 behave differently chemically which is consistent with the fact that the nanocrystalline catalysts are less active on a surface-area basis. Accumulation of H20 on the Pd/pCeO2 surface during reaction is significant but not on the Pd/nCeO2 surface. This suggests that the rate limiting step may be H2O desorption on Pd/pCeO2 while for Pd on nCeO2 adsorption of methane appears to be the slow step. The ISS data indicate that the outermost atomic layer of Pd/nCeO2 consists mostly of O and C, which is not the case for Pd/pCeO2. Site blockage by these species may also contribute to the lower activity on a surface-area basis of Pd/nCeO2 compared to Pd/pCeO2.

The electrical resistivity as a function of temperature (4K to 673K) of several electrodeposited nanocrystalline materials (Ni, Ni-Fe, Co) has been examined. The contribution of the grain boundaries to the electrical resistivity was quantified in terms of a specific grain boundary resistivity, which was found to be similar to previously reported values of specific grain boundary resistivity for copper and aluminum obtained from studies involving polycrystalline materials. In the high temperature range, the resistivity of the nanocrystalline samples was monitored as a function of time. The observed time dependence of the resistivity at elevated temperatures was correlated to microstructural changes in the material. The study has shown that electrical resistivity is an excellent characterization tool for nanocrystalline materials giving useful information regarding grain size and degree of thermal stability, as well as some insight into the grain growth kinetics at various temperatures.

Rutile nanoparticles containing voids or cavities have been characterized using transmission electron microscopy. The general morphology of the voids has been determined from images of nanoparticles in different orientations. In general, the longest dimension is along the c axis of rutile. Many of the voids show a prismatic morphology with dipyramid terminations. The prism consists of primarily four {110} faces with rounded or faceted comers between the primary faces. The pyramidal terminations can appear ovoid or faceted. A major facet plane of the pyramids is (101). A model consistent with the morphology of many voids in rutile nanoparticles is proposed.

An Ultrasonic Force Microscope capable of imaging elastic modulus variations with nanometer resolution has been developed by modifying a Scanning Probe Microscope. Images of ultrasonic properties have been simultaneously obtained with the topography images. The technique has been utilized to characterize nanoscale copper droplets and grains deposited on a quartz substrate by ionized cluster beam deposition. Images of the same region obtained with atomic force microscope, lateral force microscope, and ultrasonic force microscope are compared. The origin of image contrast in ultrasonic force microscopy and its utilization for quantitative elastic property measurement of nanometer particles are discussed.

A mass spectrometry method (Electrospray Mass Spectrometry [ESMS]) for analyzing organometallic precursors of nano-materials is described. We show that application of low-cone voltage ESMS is a useful technique for the rapid analysis of intact organometallic precursor molecules when both positive and negative ionic modes are analyzed. This method shows promise for extrapolation to analysis of the dynamics of growth in nano-scale materials.

With the help of a spectral formalism recently formulated, we study the effects in the optical response of the material properties of a nanoparticle lying over a substrate. A spectral representation was formulated to calculate the optical response of spheroidal nanoparticles including multipolar effects. We present our results in terms of Differential Reflectance spectra that can be compared directly with measurements. We have found that multipolar contributions depend in the shape of the particle and type of substrate.

In recent years there has been a growing interest in cheap and easy production techniques for transparent conducting thin films. One way of making these uses a nanoparticle dispersion. We prepared thin films of tin doped indium oxide by spin-coating of a solution of nanoparticles. The sintering behavior of these ceramic particles was studied by dielectric spectroscopy and by grazing incidence X-ray diffraction. The grain growth was found to start at 1000°C and to be prominent at 1250°C. However, the electrical conductivity reached a maximum below these temperatures.

Our research on new cathode nano-materials for advanced lithium batteries has focused on the hydrothermal method for synthesis. We have synthesized two novel manganese vanadium oxides using the hydrothermal reactions of vanadium (V) pentoxide, [N(CH3)4]MnO4, and MnSO4 with an organic templating cation at 165°C. The 6-type [N(CH3)4]zMnyV2O5*nH2O has a monoclinic structure, a= 11.66(2)Å, b=3.610(9)Å, c= 13.91(4)Å, β= 108.8(2)°. It has a disordered V2O5 double layer and the Mn and N(CH3)4 ions reside between the layers. The γ-type MnV2O5 is orthorhombic, belongs to the space group Pnma, a=9.7585(2) Å, b=3.5825(l)Å, c= 11.2653(2) Å. These compounds were also characterized by electron microprobe, FTIR and TGA. They reacted readily with lithium, and their electrochemical behavior in lithium cells was determined.

We have applied Atomic Number Contrast Scanning Transmission Electron Microscopy (Z-Contrast STEM) and STEMIEELS (Electron Energy Loss Spectroscopy) towards the study of colloidal CdSe semiconductor nanocrystals embedded in MEH-PPV polymer films. Z-Contrast images are direct projections of the atomic structure. Hence they can be interpreted without the need for sophisticated image simulation and the image intensity is a direct measure of the thickness of a nanocrystal. Our thickness measurements are in agreement with the predicted faceted shape of these nanocrystals.

Our unique 1.3Å resolution STEM has successfully resolved the sublattice structure of these CdSe nanocrystals. In [010] projection (the polar axis in the image plane) we can distinguish Se atom columns from Cd columns.

EELS measurements on individual nanocrystals indicate a significant amount (equivalent to 0.5-1 surface monolayers) of oxygen on the nanocrystals, despite processing in an inert atmosphere. Spatially resolved measurements at 7Å resolution suggest a surface oxide layer.