TiO2-SiO2 aerogel with various TiO2 contents was successfully deposited into a microchannel. SEM, XPS and liquid-phase photocatalytic oxidation reaction of phenol were used to examine the TiO2-SiO2 aerogel's microstructure and reactivity. The TiO2 content has a significant effect on the aerogel network and its adhesion on the microchannel. High open and cross-linking or ordered macroporous structure can be formed in TiO2-SiO2 aerogels with lower TiO2 content (5wt% or 10wt%). The conversion of phenol is around 36.6% during the reaction when this aerogel incorporated microchannel is used as microreactor.

Macroporous titania gels have been prepared by the sol-gel method starting from aqueous colloidal dispersion of titania. The use of titania sol instead of highly reactive titanium alkoxide allows us to control the rate of gelation. Macroporous morphology is formed when the transitional structure of phase separation is fixed as permanent structures by the sol-gel transition. The domain size can be controlled reproducibly by changing the starting composition. The crystal structure of the titania gel is transformed from anatase to rutile through the heat treatment at 900°C, while the macroporous morphology remains unchanged.

Aiming at the growth of step free surface on mesas, we tried to suppress the formation of two-dimensional nucleation on grown surface by decreasing the supersaturation. When the supersaturation was enough small at the growth temperature below 400 °C, flat facets were formed on some mesas after the LPE growth for 30 min. We considered that these facets are formed on mesas with dislocation-free surface, considering the dislocation density of Ge substrate. AFM observation indicated that some triangle hollows with monolayer step in depth were present on these facets, but that the region among the hollows was atomically flat. It was also found that the amount and the size of the hollows were related to the growth temperature. Our results show the possibility that atomically flat Ge area beyond 100 μm2 will be obtained by the control of the growth condition.

Corrosion usually takes place and degrades material surfaces based on environmental chemistry. There are several popular ways of decreasing corrosion rates to improve the lifetime of materials and devices. As recently determined, some methods may incorporate nanostructured materials processing approaches. These include surface treatment methods, nanocomposite thin film coatings, top layer coatings and thermal barrier coatings. Test results show that the corrosion performance of materials is significantly improved as compared to materials processed using conventional methods. In the present paper, some of these studies will be analyzed, and the obtained corrosion results will be evaluated in detail for the future of corrosion processes.

Nanoscaled Iron Oxide / Silica Nanocomposite particles are produced in a pyrogenic process. The iron oxide crystallites are separated from each other and covered with a silica layer. Their size can easily be controlled by adjusting the process parameters. The amount of iron oxide can also be controlled within certain limits. Due to their size these isolated magnetic particles show a superparamagnetic behaviour. The saturation magnetisation measured depends almost linearly on the size of the iron oxide crystallites showing an increase in the magnetisation with increasing particle size. Due to the composite structure the iron oxide is chemically stable. Furthermore it shows a thermal stability which is unusual for the given oxides.

This paper reports the development of porous carbon nanoturfs using alumina templating method. The nanoporous carbon has a pore size of 4 -5 Å. The length of the pillars in the carbon nanoturf was a function of temperature. It was shown that the pyrolysis of the polymer precursor reduces the dimensions of the polymer only in axial direction as compared to radial direction when it is formed inside the nanochannels.

We report on molecular dynamics calculation of few selected metal clusters by means of classical many-body potential. Despite simplicity of the approach, structural and thermodynamic properties have been achieved, such as an estimation of melting temperature lowering with size. As expected, coexistence ranges are observed instead of a single temperature transition. Phonon spectra have been also evaluated. Thermal atomic displacements at low temperature have been, in turn, estimated by means of Bose statistics.

This work is intended as a step toward computer aided interpretation of cluster characterization by X-ray's or electron beams. Therefore, X-rays diffraction patterns and near edge electron energy loss have been simulated for different model structures in order to provide insights on those characterization technique capabilities.

The addition of carbon nanotubes (CNTs) to a polymer matrix is expected to yield improvements in both mechanical and electrical properties. The focus of this paper is to give a snapshot of our current work on CNT-filled thermoplastic polymer textile fibers and the enhancement of their electrical properties. The challenge is to determine the type and size of nanotubes that are most effective for a given application, and how they should be dispersed or modified to interact with the polymer. The objective of this work is to develop an understanding of how the processing methods and properties of nanotube polymer composites are related to the geometry of the nanotubes used, their orientation, and their loading fraction. It will then be possible to design desired composite properties by controlling the relevant process variables.

The research described in this paper primarily involves mesoscale simulations (dissipative particle dynamics) of packed assemblies of oriented CNTs suspended in a polymer matrix. Computer simulations have been carried out to study the effect of processing conditions, aspect ratio of CNTs and effect of electric field on electrical conductivity. The percolation threshold required to achieve an electrically conductive polymer-CNT fiber can be predicted for given set of process variables. The model predictions are compared with the predictions of classical percolation theory, and with experimental data from measurements of bulk resistivity from CNTs dispersed in thermoplastic polymers.

Magnetic nanoparticles embedded in polymer matrices have excellent potential for electromagnetic device applications like EMI noise reduction. We have synthesized polystyrene (PS) and polypyrrole (PPy) composites by controllably dispersing bare and PS-coated Fe nanoparticles. These nanocomposites were processed as spin-coated thin films as well as in bulk form. The processing conditions were optimized to achieve good uniform dispersion of the nanoparticles in the polymer matrix. SEM scans revealed clustering of nanoparticles which was particularly evident at the surface in the conducting polymer nanocomposites. Magnetic hysteresis loop measurements indicate large coercivities associated with the clusters and surface oxidation of the Fe particles. Overall, the excellent dispersion coupled with reasonable control over magnetic properties achieved in our experiments is promising for electromagnetic applications of these materials.

The understanding and prediction of complex nanostructured self-assemblies such as colloidal suspensions, micelles, immiscible mixtures, microemulsions, etc., represent a challenge for conventional methods of simulation due to the presence of different time scales in their dynamics.

We have recently successfully applied a novel computer simulations technique, Dissipative Particle Dynamics (DPD), to model the behavior of diblockcopolymers at the water/oil interface. With the use of a simple model we have performed simulations of polymer/water/oil systems at different concentrations.

We present the results of nanoscale “coarse-grained” simulations with DPD. DPD is a mesoscale simulation technique that has been introduced in order to simulate three-dimensional structures of organic polymer aggregates.

In DPD the polymer is modeled using particles which are interacting by conservative, dissipative and random forces. Particles are not regarded as molecules but rather as droplets or nanoclusters of molecules.

We have successfully applied this technique to simulate the three-dimensional structures of microemulsions, e.g. the bicontinuous phase of a surfactant in water and oil, in domains of less than 100 nm. The different structures of the polymer/water/oil system were effectively characterized with DPD and are in remarkable agreement with the experiment.

The DPD method proofed to be a reliable tool to get a better understanding of the nanostructure of self-assemblies and is therefore applicable to support the often complicated experiments or even to obtain experimentally unavai1able data.

Electrospinning derived from electro spraying is a process by which sub-micron polymer fibers can be produced using an electrostatically driven jet of polymer solution. The fibers are collected as non-woven mat and offer a high surface to volume ratio. Polyaniline is an organic conducting polymer and can be used to fabricate conducting nano fibers by blending with suitable polymers like poly methyl methacrylate. In this present work we have explored the effects of electrospinning parameters on the formation of PANI/PMMA fibers and the phase morphology of the electrospun fibers using advanced electron microscopy and scanning probe microscopy techniques.

Here we report the synthesis and investigation of iron and iron oxide nanowire arrays using mesoporous silica as a host material. In the present work a novel variant of synthesis of ordered magnetic nanowires in the mesoporous silica matrix was suggested. The method is based on the incorporation of a hydrophobic metal compound into the hydrophobic part of silica-surfactant composite. The amount of iron intercalated into the mesoporous matrix was measured by chemical analysis. In all samples it corresponds well to with the molar ratio SiO2: Fe = 9:1. To provide crystallinity of nanowires additional thermal treatment was performed. Thus prepared nanocomposites were characterized by TEM, ED, SAXS, SANS, BET and magnetic measurements. The anisotropy parameters of nanowires were determined using two non-correlated methods: temperature dependence of magnetic susceptibility and small angle polarized neutron scattering. It was found that the particle length increases with the increasing of the decomposition temperature of the metal complex. Obviously it deals with crystallization and growth of metal particles inside the pores at a constant diameter of a single particle. For iron containing sample annealed at 375 °C (form factor of nanowire is about 40), the coercive force at room temperature was found to be 145 Oe at saturation magnetization of 1.2 emu/g, which is not far from modern information storage. It was shown that particles shape and size are in good agreement with that of the pores. Particles are uniform and well ordered in the silica matrix. Thus, the suggested method leads to one-dimensional anisotropic nanostructures which could find an application as high-density data storage magnetic media.

A systematic study on the Si inter-dot distance after nucleation on silicon oxide substrates is presented. The process has been followed from the very early stages of the dot formation up to 25% of coverages. Structural characterization has been performed by means of energy filtered transmission electron microscopy, which allowed us to observe dot sizes down to 0.5 nm in radius. Silicon nanodots are shown to be surrounded by a depleted zone, where no new Si dots are observed to nucleate. The average size of such a zone ranges between 4 and 9 nm, depending on the deposition conditions. The dot radius is shown to be proportional to the depleted region size, thus indicating the scaling behaviour of the process.

A comprehensive understanding of nanotube materials requires the ability to link different carbon nanotube models, which were developed to work at different length scales. Here we describe the mapping of a molecular dynamics (MD) model for single-wall carbon nanotubes onto a wormlike chain. This mapping employs a mode analysis of the bending fluctuations of the nanotube, similar to those used in experiments [1]. The essence of this mapping is to find an appropriate bending stiffness for the wormlike cha in in order to represent the nanotube on a coarsened scale. We find that this mapping will only work well, if the wavelength probing the nanotube stiffness is sufficiently large. For single-wall (9,9) armchair nanotubes vibration modes with node distances of 3 nm underestimate the long wavelength limit of the bending constant by about 50%. This mismatch tends to increase for tubes with larger radii.

Both carbon nanotubes and carbon nanofibers were grown on a thick nickel substrate by means of microwave plasma enhanced chemical vapor deposition (MPECVD) process using 20% CH4 and 80% H2 at a temperature of 750°C and a pressure of 50 Torr. The substrate was pre-abraded with 1.0μm diamond powder and 15.0 μm diamond paste to increase the rate of nucleation. When the substrate is taken out of the reactor the film detaches itself completely from the nickel. Unusual outgrowth structures appear jutted on one section of the substrate in a symmetrical manner. These structures were very hard and, when analyzed using environmental scanning electron microscope (ESEM), Raman microscopy and transmission electron microscope (TEM), micro-trees and an abundance of multi wall carbon nanotubes (MWCNTs) and nanofibers were observed. An attempt to measure the hardness of the film using a nano-indenter was inconclusive due to the extreme hardness of the material produced.

This contribution reviews the structure formation processes that are observed in binary diblock copolymer/particle and ternary diblock copolymer/particle1/particle2 mixtures. The particle core size, the polymer domain spacing as well as the particle surface chemistry are shown to determine three distinct morphological types in particle/block copolymer composites, which is the preferential layer homogeneous distribution, the interfacial segregation and center alignment of the nanocrystals within one polymer domain. The different microstructural environments of the sequestered component that are implied by the respective particle distribution result in distinctively different optical properties of the composite and have important consequences for the prospects of metal nanocrystal/block copolymer composites as a platform for photonic crystal engineering. A detailed comparison between morphological studies and theoretical predictions will be presented that aims to better understand and control morphologies of structured cluster matter and its relation to the respective optical and mechanical properties of new microstructured composite materials.

Hexagonally mesostructured 12-phosphotungstic acid (PWA) thin films with both large pore size and hierarchical structures have been successfully prepared by using triblock copolymer templates for the first time. The films is composed by three kind of structures; PWA Keggin anion, monoclinic crystal structure consisting of PWA Keggin anion and organic part (hydrophilic component) of block copolymers, and the hexagonal mesostructure of self-arrayed PWA and block copolymers. The calcined PWA films show better electrochemical properties such as a faster faradic processes and larger specific capacity than normal P WA clusters.

An ab-initio study of the electronic structures and optical absorption spectrum of the guest Cs and Na atoms absorbed in the pure silica ITQ-4 zeolite channels was carried out using density functional theory (DFT) and plane wave basis. Completely different geometries were found for doped Cs and Na in the channels. For Cs doping, a zig-zag chain was formed along the channel and a metallic band structure was obtained. However, a dimer structure around the channel center was found for Na doping and a narrow band gap semiconductor was observed for this system. Correspondingly, the calculated optical absorption spectrum also showed distinctive characters for Cs and Na dopings. Our theoretical results for Cs doping are compared with experimental measurements and previous DFT calculation with local orbital basis; better agreement with experiments has been reached than the previous calculation. For the Na doping, our theoretical predictions need to be confirmed by future experiments.

A process of self-assembly induced by electro-chemical etching was used to produce nano and micrometer scale pyramid-structures on (100) surfaces of gold. The pyramids grew in a self-similar fashion with the facets aligned in (114) plane. Using the unique characteristics of the self-similar pyramid structure, plastic compression of the pyramids by a flat-surface platen was performed to study length scale effects in the plastic deformation. A continuum limit analysis and a finite element simulation as well as molecular dynamics simulations were carried out to predict the deformation and load-displacement behavior of the pyramid compression. The limit analysis predicts that the load of compression is proportional to the square of the contact-compression displacement. The continuum analysis provides estimation on the asymptotic behavior of the elastic-plastic load-deflection response of the pyramid under compression for a large value of displacement. The three dimensional molecular dynamics simulation was utilized to study the dislocation activities during the early stage of the pyramid compression. Experiments were also carried out by pressing the pyramids with an atomically flat mica surface. The deformation of the compressed pyramid was measured using an Atomic Force Microscope (AFM). The continuum analyses predict size independent values of the slope change of the pyramid facets near the contact edge, caused by plastic deformation. However, atomistic simulation predicts an opposite value of the slope change to the prediction of the continuum analyses. The AFM measurements of the slope change show size dependent transition from the prediction of the continuum analyses to that of the atomistic simulations. The transition data provide an apparent characteristic length of the size dependence of plastic deformation in a small volume. Molecular dynamics show that at very small length scale the size effect is strongly influenced by surface adhesion effects.

Flexible and temperature tolerant nano-hybrid membranes consisting of zirconium (titanium) oxides and polydimethysiloxane (PDMS) with the different molecular mass of 4500 and 600 have been synthesized by sol-gel processes. The membrane of zirconium/PDMS=2 (in molar) showed enhanced thermal stability and flexibility up to 300 °C due to the presence of cross-linkable inorganic nano-phase in the hybrid macromolecular matrix. The membrane becomes proton conducting polymer electrolyte when doped with 12-phosphotungstic acid (PWA). The proton conducting properties of the hybrid membranes with various PWA concentration were measured in the temperature range from room temperature to 150°C under saturated humidity conditions. A maximum conductivity of 2×10-2 S/cm was obtained at 150°C when the PDMS/zirconium oxides hybrid matrix was changed to gel state due to the higher water activity at elevated temperatures.