Thiol-coated gold nanoparticles with a diameter of approximately 7.5 nanometers and a narrow particle distribution were prepared from sodium tetrachloroaurate under phase transfer conditions. The thiols used were 1-mercaptododecane (1) and 1-mercapto-9,11-heptadecadiyne (4). The particles were cast onto thin films of polyaniline and poly (3,4-ethylenedioxythiophene), as well as onto thiol-coated versions of the same polymer. Surface modification of the polymers with long chain thiols encourages the spontaneous self-assembly of the particles into twodimensional arrays and may offer a unique method for stabilization of nanoparticle assemblies on polymer substrates.

Nanowires and nanotubes have attracted significant interest during recent years due to their novel electrical, magnetic, and photonic properties. Quantum confinement, proximity interaction, and surface plasmon enhancement effects are among a few unique phenomena associated with these materials. A convenient procedure to prepare these materials is through anodized aluminum oxide (AAO) template synthesis. Nanoporous AAO membranes with pore diameters ranging from 10 to 200 nm can be prepared with anodization in oxalic, sulfuric and phosphoric acids under various reaction conditions. With repeated anodization-etching cycles, highly ordered straight channels can be prepared through self-organization. With electro- and electroless deposition, a variety of nanowires and nanotubes such as Ni, Co, Au, Pb, Bi, etc. have been prepared. The synthesis, characterization, and physical properties of these materials are presented.

Evaporation induced self assembly (EISA) within microdroplets produced by a vibrating orifice aerosol generator (VOAG) has been used to produce monodisperse mesoporous silica particles. This process exploits the concentration of evaporating droplets to induce the organization of various amphiphilic molecules, effectively partitioning the silica precursor (TEOS) to the hydrophilic regions of the structure. Promotion of silica condensation, followed by removal of the surfactant, provides ordered spherical mesoporous particles. Using the VOAG we have produced highly monodisperse particles in the 5 to 10 μm diameter range. The cationic surfactant CTAB typically leads to hexagonal mesostructure with mean pore size of about 2 nm and specific surface area around 900 m2/g. We have also shown that the pore size in CTABtemplated particles can be increased to 3.8 nm by incorporating trimethylbenzene as a swelling agent. The TMB prefentially locates inside and swells the hydrophobic regions of the surfactant mesostructure. Pore size can also be varied by the choice of amphiphile. Hexagonally ordered particles have been produced using the nonionic surfactant Brij-58 and block copolymer F127. These powders possessed mean pore size 2.8 nm and 6.9 nm, respectively. The uptake of alkyl pyridinium chloride molecules have recently been measured, revealing an uptake capacity that is explained by surface adsorption (as opposed to simple pore infiltration). Kinetics of the uptake process are still be analyzed.

Immobilized polymerized electroactive vesicles (IPEVs) are submicron biocapsules capable of storing charge in confined environments and chemisorbing on surfaces. Methods to immobilize stable submicron sized electroactive vesicles and the means to measure electroactivity of IPEVs at nanolevels have been demonstrated. IPEVs can withstand steep potential gradients applied across their membrane, maintain their structural integrity against surfaces poised at high/low electrical potentials, retain electroactive material over several days, and reversibly mediate (within the membrane) electron flow between the electrode surface and vesicle interior. IPEVs have strong potential to be used for charge storage and electron coupling applications that operate on the submicron scale and smaller.

Si/SiO2 multilayers (MLs) have been prepared under different deposition temperatures (TS) by ion beam sputtering. The annealing at 1200°C leads to the formation of Si nanocrystals in the Si layer of MLs. The high resolution transmission electron microscopy images clearly demonstrate the existence of Si nanocrystals, which exhibit photoluminescence (PL) in the visible range when TS is ≥ 300°C. This is attributed to well-separation of nanocrystals in the higher-TS samples, which is thought to be a major cause for reducing non-radiative recombination in the interface between Si nanocrystal and surface oxide. The visible PL spectra are enhanced in its intensity and are shifted to higher energy by increasing TS. These PL behaviours are consistent with the quantum confinement effect of Si nanocrystals.

Organic-inorganic hybrid mesoporous materials containing homogeneously distributed ethane group in silica framework were prepared using 1,2 bis(trimethoxysilyl) ethane (BTME) as a precursor and alkyltrimethylammonium chloride/bromide surfactant as a template. Characterization of the materials was performed using XRD, TEM/SEM, 29Si– / 13C– NMR, and N2-adsorption. Hydrothermal synthesis assisted by microwave heating produced a 1-3 micronsized hybrid material with spherical morphology in substantially reduced time. Bifunctional materials containing BTME and either aminopropyl- or mercaptopropy- group within the same silica framework were also prepared with or without the presence of a swelling agent, mesitylene. Mn-salen complex tethering on the hybrid material produced a catalyst with a somewhat enhanced performance in cyclohexene etherification using TBHP as an oxidant. Testing of the hybrid material as a reverse phase HPLC column material after C18 surface-functionalization demonstrated a promising result, which warrants further optimization of synthesis parameters.

Large monoliths with periodic mesopores in a macroporous web-like network structure are prepared using a diol-modified silane as silica precursor and lyotropic liquid crystalline phases of surfactants in water as structure-directing agents. The surfactant concentration is varied from 5 to 40wt%. Highly porous materials are synthesized applying two different drying procedures: supercritical drying with CO2 or ethanol, in addition to ambient pressure drying including surfactant expulsion via silanisation treatments with trimethylchlorosilane or hexamethyl disilazane. The monolithic materials show a very unique macro- and mesostructure which is characterized by N2-sorption measurements, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

Organically functionalized mesoporous silica films were prepared by a novel synthesis procedure. The synthesis procedure involves a vapor infiltration technique for mesostructured silica films prepared through a spin-coating process. Organic-functional groups were incorporated into the mesochannel wall by the vapor infiltration treatment using organosiloxanes. The structural stability of spin-on mesostructured silica films is generally low, resulting in a structural shrinkage or a collapse of the mesostructure under calcination process. On the other hand, the treated films did not contract during calcination, indicating high structural stability. A contact angle of water on the treated film was large, showing high hydrophobicity. FTIR analysis suggested that the residual silanol groups were replaced with the organosilyl groups after vapor infiltration treatment. The increase in the film thickness was hardly observed under vapor infiltration, suggesting no deposition of organosiloxanes vapor on the surface of the film.

Magnetic nanocomposite thin films formed by cobalt ferrite dispersed in silica matrix were prepared by sol-gel process using tetraethylorthosilicate (TEOS) as a precursor of silica, and metallic nitrates as precursors of the ferrite. The films were prepared with 5–50 wt. % ferrite contents and deposited on substrate using the dip-coating process. The films obtained were adherent, transparent, homogeneous and free of microcracks, with thickness between 30 and 500 nm. The films obtained presented crystalline CoFe2O4 phases dispersed in SiO2 amorphous matrix and saturation magnetization of approximately 9 emu/g considering the composite mass and 30 emu/g considering the ferrite mass.

A Magic Angle Spinning (MAS) NMR probe has been designed allowing the in-situ measurements of NMR spectra of working catalyst. The probe was built following the original design of M. Hunger [Hunger, 1995 #2]. It allows the magic angle spinning of powder samples up to 3.5 kHz, under gas flowing conditions, and at temperatures up to 573K.

The development, operation and applications of a novel continuous chemical reactor system are described. The system, known as a Multiple Stream Mixer/Reactor (or MMR), produces nanoparticles by direct precipitation from two or more reactant solution streams in an extreme energy density, ultraturbulent, collision reaction region. Sensors and a control system are employed to assure constant mixing conditions and desired stoichiometry in the reaction region. The interaction chamber is designed to allow macro-, meso- and micromixing during processing. This allows control of product purity, yield, size, size distribution, and phase purity. Typical nanoparticle diameters in the one to ten nanometer range are often achievable, with tight size distribution. The MMR can be scaled from development quantities to tons/hour for production applications.

By using Krätschmer-Huffman synthesis and HPLC separation method we have isolated a series of novel fullerenes and endohedral fullerenes. Various spectroscopic techniques, e.g., MS, NMR, UV-vis-NIR, TEM, X-ray diffraction spectrometry etc., were adopted to characterize the isolated fullerenes. Several fullerenes were revealed to hold novel structures and electronic properties. For examples, C80(D5d) was isolated and characterized to have an ellipsoidal structure which is in fact one of the shortest SW-nanotubes; The isolation of Sc2@C66 breaks the well-known isolated-pentagon-rule (IPR) for the first time, which shows that the unconventional fullerenes may be dramatically stabilized through encaging metal atoms; Sc2C2@C84 is a novel molecular endohedral fullerene in which the Sc2C2 cluster rotates rapidly along the main C2 axis of C84(D2d). This fullerene is predicted to be a molecular magnet and may be used as nano-switcher in electronics.

Highly ordered mesoporous silica particles with sizes in the micron to sub-micron range are of great interest due to their applications as catalysts and filler materials. Currently, mesoporous silica particles are synthesized using large amounts of solvent, which is impractical for large scale-up in industry. This paper reports on a high-energy ball milling process that has been employed to create micron to sub-micron sized mesoporous silica particles starting from a silica xerogel prepared by a surfactant self-assembly sol-gel process. We have studied the effect of parameters such as milling media (e.g., zirconia, stainless steel, and steel centered nylon balls), milling time, the presence of surfactants during milling, particle size, and pore structure. Results from transmission electron microscopy (TEM), scanning electron microscopy (SEM), Xray diffraction (XRD), and nitrogen adsorption demonstrate the feasibility of producing large quantities of mesostructured particles by a simple milling process.

We compare the adsorption of 1,1'-biphenyl-4,4'-dimethanethiol (BPDMT) on gold and cobalt surfaces. The molecular orbitals, identified from combined photoemission and inverse photoemission studies, exhibit shifts in binding energies with different deposition methods and substrates. These shifts indicate that this potential molecular dielectric exhibits stronger bonding to cobalt surfaces than gold surfaces.

In this study, a series of FexPtyCu100-x-y nanoparticles were chemically synthesized by solution-phase reduction of platinum and copper reagents and thermal decomposition of iron pentacarbonyl in the presence of stabilizers oleic acid and oleyl amine. As-prepared particles had a chemically disordered face-centered cubic (fcc) lattice with an average diameter of 3.5 nm. The particle size, and the corresponding size distribution were controlled by varying the organic surfactant (oleic acids, etc.), its concentration, and the reaction temperature. These particles were well dispersed in hydrocarbon solvents and self-assembled into two or three dimensions particles arrays with a variety of closepacking arrangements. Domain of monolayers, bilayers and multilayers of particles arrays were frequently detected in TEM specimens. Both cubic close-packed (ccp) and honeycomb arrays were also uniquely observed. It was also demonstrated that the controlled organic surfactant layer (organic capping) play a crucial role in determining assembly dimensions and symmetry as well as particle packing arrays.

Micellar solutions of polystyrene-poly(acrylic acid) block copolymers are studied in the jammed regime. Increasing attraction between soft spheres, both the rheology and dynamic light scattering show a re-entrant liquid to glass transition. The dynamics was also investigated at an attraction strength above the re-entrant transition line. Increasing concentration of sticky soft spheres in this region, the particle dynamics shows a remarkable extended logarithmic decay. The theoretical predictions of mode coupling theory agree well with our results.

In this presentation, we report the self-assembly of monolayer and multilayer nanorings of PbSe nanoparticles. PbSe nanoparticles were synthesized by using a high temperature precipitation method. The nanoparticles are about 5 nm and appeared as truncated octahedral enclosed by the {100} and {111} crystal facets of fcc structure. The large area monodisperse self-assembly nanoarrays were obtained by dropping the high concentration solution of PbSe nanoparticles on the carbon grid. The nanoparticles are hexagonal close packed and oriented randomly in the nanoarrays. By diluting the solution for large area self-assembly, self-assembly of monolayer and multilayer nanorings can be achieved. The nanoring formation is determined by hydrodynamics, surface effects, and interaction between the nanoparticles and carbon grid.

Electrochemical activity of differently pretreated single-wall subnanometer-diameter molybdenum disulfide tubes (nMoS2) was tested and compared with layered MoS2 material. In as prepared and de-iodized nMoS2 samples a significant increase in the charge capacity has been found compared to the one measured in dispersed nMoS2 or layered MoS2. Enhanced electrochemical activity has been attributed to a particular one-dimensional topology of nanotubes bundles. Electrochemically doped samples were then studied with X-band ESR. While undoped nMoS2 show no X-band ESR signal between room temperature and 4 K we found in heavily doped nMoS2 samples two distinct ESR components: a narrow component with a linewidth of few Guass and a broad component with a linewidth of more than 800 G. The broad ESR component is characteristic of Mo d-orbital-derived band. The temperature dependence of the ESR spin susceptibility and the linewidth of the broad ESR component can be discussed either in terms of conducting electrons coupled to defects or in terms of random-exchange Mo Heisenberg chain model.

The synthesis of reflective silvered polyimide films by a single-stage auto-metallization process entailing the (hexafluoroacetylacetonato)silver(I) complex dissolved in solutions of poly(amic acid)s and polyimides formed from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropanedianhydride (6FDA) and 2,2-bis(4-(4-aminophenoxy)hexafluoropropane (4-BDAF) is described. Heating cast silver(I)-poly(amic acid)/polyimide films effects silver(I) reduction and nanoaggregation giving reflective films for Ag concentrations from 6-10 wt %. A6% silver film gives specular reflectivies greater than 80%. Films prepared from the soluble fully imidized form of 6FDA/4-BDAF were less reflective.

In B2-type FeAl, supersaturated vacancies retained upon rapidly quenching are absorbed near surface during an aging treatment, being agglomerated into nano- to meso-clusters through the absorption process. Eventually, surface morphology is self-patterned in nano-order by the vacancy clustering. If FeAl was not quenched from high temperature or plastic strain remained near surface, the surface self-patterning never occurs, indicating that the change in surface morphology is caused by the clustering of supersaturated vacancies. The clusters have specific shape with cluster surfaces faceted toward {100} planes. Thus, the shape of the clusters formed near surface is controllable by changing surface orientation. Vacancy cluster size and its distribution density can be also controlled by varying the concentration of supersaturated vacancies and/or the clustering condition. These indicate that the vacancy clustering is a unique process to efficiently pattern the surfaces of metals, alloys and intermetallics in nano-scale.