Transparent monolithic aerogels based on silica, the bioderived polymer chitosan, and coordinated ions have been employed to serve as a three-dimensional scaffold decorated with Au, Pt and Pd ions. The coordination states of metal ions and the initial gel in one or several of the ions are established in the thickness of the monolith that is produced by supercritical CO2 extraction to form the aerogels. Also in this work, it has been found that the Au(III) aerogels can be imaged photolytically in the two planar dimensions. The spatially controlled photolysis produces nanoparticles, (Au)n in the range of from 5 to 85 nm, for example, that constitute two dimensionally imaged arrays whose volumetric concentration also varies in the third dimension. These images microarrays of nanoparticles provide a basis for localization and detection of thiols, disulfides, amino acids and protein molecules. The formation of these arrays, including the dependence of their properties on light intensity, frequency and exposure, and distribution of target molecules and ions in the initial aerogel is presented.

This work presents the first results of synthesis of framework binary phosphates of zirconium and transition metal cations (Co, Cu, Ce) via nanocomposites of starting inorganic salts with citric acid and studies of their structure genesis. Nanoparticles of layered Zr phosphates with typical sizes in the range of 18–24 Å are formedat the mixing stage. Less basic Cu and Co cations are mainly octa-coordinated with both phosphate groups of those nanoparticles and citric acid molecules. At subsequent thermal treatment, Cu and Co cations are incorporated within Zr phosphate nanoparticles acquiring a low coordination approaching a tetrahedral one while rearranging the nuclei structure into that of a framework type. Removal of citric acid by heating under air at 200–300°C preserves the size of nanoparticles while their ordered stacking forms mesoporous structure with a narrow pore size distribution ∼ 50 Å and specific surface area up to 200 m2/g after calcination at 600°C. The binary phosphates promoted by a small amount of Pt were found to be effective catalysts of NOx selective reduction by decane in the oxygen excess not subjected to coking with a high and stable performance at high space velocities in the presence of steam.

Reactive metallic fragments that are formed by the decomposition of organometallic complexes, undergo a nucleation and growth process that gives rise to the formation of nanocrystals. In the absence of stabilizing molecules, the aggregation process is restricted mainly due to the decreasing mobility of the particles and their declining diffusional rates as a function of their increasing size. On the other hand, in the presence of a polymer in the reaction medium, the growing metallic particles are stabilized by the surface adsorption of the polymer chains, thus lowering their surface energy and creating a barrier to further aggregation. Studies of the nucleation and aggregation kinetics of metallic particles formed from the decomposition of organometallic precursors have been used to shed light on the mechanism of their formation. In these studies, the rate of decomposition of the precursor organometallic complexes used has been considered to represent the overall rate of the process. Moreover, it has been implicitly assumed that the formation kinetics of the metal nanoclusters directly coincides with the decomposition kinetics of their precursors. In this study, we attempt to decouple the kinetic characteristics of the various steps that comprise the overall nucleation and aggregation process cobalt oxide nanoclusters. A combination of infrared and x-ray photoelectron spectroscopies, and particle size determination by dynamic light scattering, are used to identify the individual contribution of each step to the overall mechanism of metal nanocluster formation.

In recent years, methods have been developed for the generation of complex ordered nanocomposite materials through organic templating of inorganic structures. One approach involves preparation of composite materials by an evaporation induced self-assembly process involving organization of organic surfactants and formation of inorganic silica from soluble precursors. Recently, we have shown that deep-UV light (185–254nm) is efficient at removing the surfactant microphase for a routine production of well-ordered mesoporous silica thin films. Here we probe the evolution of surfactant removal from nanocomposite thin film silica mesophases as a function of deep-UV exposure using a combined application of FTIR and single wavelength ellipsometry. Taken together, these data indicate that surfactant removal occurs in a step-wise fashion with the formation of oxidized intermediates prior to complete removal of the surfactant from the thin film.

Si/SiO2, RE2O3/Si/SiO2 and RE2O3/Si/Al2O3 films were sputtered. Si/SiO2 films were annealed to 1100°C for 30 min in Ar. RE2O3/Si/SiO2 films were annealed to 700°C, 1000°C, or 1100°C for 30 min in Ar. RE2O3/Si/Al2O3 films were annealed to 700°C for 30 min in Ar. Raman spectra and photoluminescence (PL) obtained for the Si/SiO2 films show relation between Si nanocrystal (nc) presence, Si nanoparticle (np) PL and Si target area. Nd2O3 co-sputtered films presented PL for the (4F5/2, 2H9/2) → 4I9/2, 4F3/2 → 4I9/2, 4F3/2 → 4I11/2, and 4F3/2 → 4I13/2 transitions. Er2O3 co-sputtered films presented PL for the 4I11/2 → 4I15/2, and 4I13/2 → 4I15/2 transitions. Tm2O3 co-sputtered films presented PL for the 3H4 → 3H6 transition. Different spectral shapes were observed for the infrared (IR) PL of the Er3+ ions and of the Nd3+ ions for the RE2O3/Si/Al2O3 films with respect to the RE2O3/Si/SiO2 films.

Metallic copper nanostructured particles were synthesised by thermal decomposition of a CuC2O4 precursor obtained via the precipitation reaction between Cu(NO3)2·6H2O and Na2C2O4 in the present of hydroxyl propyl methyl cellulose (HPMC). X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM) and thermogravimetric analysis (TG) were used to characterise the particles and their evolution during the transformation to metallic copper. We highlight the nanostructured nature of the oxalate precursor, which is made up of anisotropic nanosized buildings blocks (25nm by 40nm). These produce an anisotropy in the oxalate particle and influence the decomposition pathway. The results show the evolution of the nanostructure as a function of degree of reaction and a possible kinetic model is discussed.

UV curable polymers are prevalent in microelectronic applications. Several advantages are associated with UV curing such as rapid cure, solvent free systems, application versatility, low energy requirements, and low temperature operation. To be used in electronics the films must posses the following attributes: high glass transition, barrier properties, low shrinkage, flexibility, and enhanced mechanical properties. The area of polymer-clay nanocomposites have been widely investigated by researchers and improved mechanical, thermal, and barrier properties were reported. Most researchers have attempted nanocomposite formation by melt mixing or in situ polymerization. Little is understood on UV curable nanocomposites. This paper seeks to examine nanoclay-containing polymers using organomodified montmorillonites in UV curable systems and the effects of such clay inclusions on the properties of UV cured films. By x-ray diffraction it appeared that intercalated structures were formed. In the case of an epoxy acrylate formulation an increase in glass transition temperature was observed for formulations containing clay.

The development of new materials for organic/plastic electronics allows us to fabricate novel devices through unconventional approaches. The ‘soft lithography technique’ has been widely used in replicating and fabricating small features. This technique is a low cost alternative to photolithography by generating structures from masters to substrates, which employ ‘elastomeric materials’, such as highly stretchable silicon elastomer, polydimethylsiloxane (PDMS) to replicate or transfer the original features to a variety of substrates by molding and printing processes. Since the resolution of pattern transfer significantly relies on the performance of polydimethylsiloxane (PDMS) stamp materials, commercial PDMS materials have shown limitations in high fidelity pattern transfer due to their low physical toughness and high thermal expansion coefficients. For those reasons, pattern fabrications using conventional PDMS materials are unable to satisfy our set of diverse demands, especially in the area of nano-scale replication. To achieve high performance in molding and printing, here we introduce a new strategy, design and synthesis of a modified PDMS silicon elastomer that is a stiffer and photocurable element to achieve our specific task of nano-scale resolution soft lithography. We then demonstrated its unique capabilities for the case of nano-features (300 nm wide) with narrow and tall heights (600 nm height) of photoresist, which is one of the most challenging ‘nano-patterning’ tasks in advanced soft lithography, which is often limited in its use at the nano-scale with other commercially available elastomers.

A novel approach for the synthesis of carbon nanotubes strengthened nanostructured tungsten carbide was investigated, in which nanophase tungsten powders are carburized by C2H2 instead of CO and a fraction of decomposed carbons were in situ converted to nanotubes. In this way, the composite powders of nanocrystal WC-Co and carbon nanotubes have been in situ prepared. The composite WC-Co powders were then hot pressed into bulk alloy which shows a exceptionally high microhardness up to 3307 kg/mm2. It is proposed that carbon nanotubes with extra high Young's modulus (1.8 Tpa) play both roles on strengthening the composite matrix and prohibiting growth of WC grains, which results in the great improvement of the mechanical properties of the samples. The average grain size of the prepared WC-Co hard alloys was estimated to be less than 100 nm. The effect of hot press temperature on the mechanical properties of the prepared alloys was also studied in detail.

Based on the microscopic observations and measurements, the mechanics behaviors of the nanostructured material (the surface-nanocrystallized Al-alloy material) at microscale are investigated experimentally and theoretically. In the experimental research, the hardness-indent depth curves or relations are measured by using both the method of randomly selecting loading points on the specimen surface and the continuous stiffness method. In the theoretical simulation, based on both the material microstructure characteristics and the experimental features of the nanoindentation, the microstructure cell model is developed and the strain gradient plasticity theory is adopted. The material hardness-indent depth curves are predicted and simulated. Through comparison of the experimental results with the simulation results, the material parameters and the model parameters are determined.

In this paper, we report the synthesis and characterization of three novel water-based nanocomposite coatings. Throughout the paper, these coatings will be referred to as coatings 1, 2 and 3. The coatings are silica-based and are sol-gel derived using surfactant assemblies, with aluminum perchlorate as a catalyst. After synthesis, curing causes cross-link polymerization of silica, forming Si-O-Si network. The formation of this 3-Dimensional network can be verified using Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). Incorporating metal oxide nanoparticles gives the material unique properties.

Due to the non-equilibrium nature of deposition techniques, thin films can exhibit an energetic state far from thermodynamic equilibrium. Energy supply can stimulate a transition into other metastable states. Examples of metastable phase formation presented in this work are thermally stimulated solid state reactions in metallic nanometer Al/Co/Ni multilayers and phase formation and transition in metallic alloy films of the elemental materials system Fe-Cr. An interesting application illustrates the technical potential of metastable nanometer films.

In situ observation of the genesis and growth of silica-alumina structures during the sol-gel process has been carried out. Although the gross structure of the gel network is kinetically stabilized, in situ AFM study reveals that at nanometer scale, the internal structure of the gel is dynamic as shown by the rich and complex morphological transformations.

Protein thin film (mainly silk fibroin) was prepared by pulsed laser deposition (PLD) with 1064nm IR-beam and via colloid chemical routes. Thickness, surface roughness, and microstructures of the deposited film were examined by quartz crystal microbalance sensor, field emission scanning electron microscope (FE-SEM), and atomic force microscope (AFM). The laser power density was varied systematically for PLD to control the microstructures of the film and the secondary structure (β-sheet, α-helix, or random coil) of the protein. Secondary structure of the target and film was examined by FT-IR. Films prepared by PLD comprise by agglomerated particles with their primary particle size around 30nm. The size of the primary particles was uniform, especially for the film prepared at low laser power density. At low laser power density, proportion of β-sheet increased and that of random coil decreased. Proportion of random coil was also increased by the wet colloidal process. PLD with low power density is most suitable to preserve the secondary structure in the protein thin film.

We a pplied ellipsometric porosimetry and variable-energy positron annihilation spectroscopy to the pore characterization of spin-on-glass silicon-oxide-backboned porous thin films with different relative dielectric constants between 2.3 and 3.2. It was found that the relative dielectric constant decreases linearly with increasing open porosity deduced by ellipsometric porosimetry. Comparison of the open porosity with the average pore size deduced by positron annihilation lifetime spectroscopy suggested that mesopores less contribute to open porosity and are not so effective in decreasing film relative dielectric constant in comparison with micropores.

Changes in the crystallographic phase stability of individual layers in a multilayered thin film stack are expected to have a significant influence upon the functional properties of the structure. The ability to predict and tune these phase stability states is of relevant importance in order to maximize the functional properties of the multilayer. A classical thermodynamic methodology, based upon competitive volumetric and interfacial free energies, has been used in the prediction and subsequent confirmation of the hcp to bcc phase stability in a Ti/Nb multilayer. An outcome of this model is a new type of phase stability diagram that can be used to predict the hcp Ti and bcc Ti phase stability as a function of length scale and volume fraction. The Ti layers were subsequently alloyed with a bcc-stabilizing element. The alloyed sputtered deposited Ti layers were able to stabilize the bcc Ti phase to a larger layer thickness as compared to the unalloyed Ti/Nb multilayers. The percentage of alloying element added to the Ti layer in controlling the critical transition thickness between the two phase states had good agreement with the predictions proposed by the thermodynamic model.

We report the creation of single crystal tungsten nanorods with unusual simple cubic β-phase. These novel nano-structures were grown by oblique angle sputter deposition with substrate rotation through a shadowing effect. Transmission electron microscopy (TEM) diffraction patterns from individual nanorods clearly show the single crystal structure. It is evident from TEM diffraction measurements, during the oblique angle deposition, both β-phase W(100) and α-phase W(110) islands exist at the initial stages of growth. However, at later stages of the growth the β-phase structure dominates. This is in contrast to the sputter deposition at normal incidence where only the thermodynamically stable bcc α-phase W(110) polycrystalline films were formed when the film grew to a certain thickness. We explain our results by using the shadowing and adatom mobility mechanisms: At the initial stages of growth, the β-phase W(100) islands grow taller due to the lower adatom mobility on these islands. The taller β-phase W(100) islands survive in the competition during oblique angle growth and form isolated nanorods in the later stages, while the shorter α-phase W(110) islands stop growing due to the shadowing effect. In addition, our Monte Carlo simulation results agree well with the experimental measurements.

Pulsed laser deposition (PLD) technique was used to grow alumina (Al2O3) thin films on (100) silicon substrate under different deposition conditions. The relationship between Al2O3 thin film thickness, hardness, elastic modulus, surface morphology and PLD parameters such as laser energy and substrate temperature was investigated. The Film thickness was found to increase with an increase in laser energy and to decrease with an increase in substrate temperature. The film hardness and elastic modulus increases as substrate temperature increases. We have also shown that films are amorphous at lower substrate temperatures and transform to mixture of amorphous and crystalline phases. The ratio of amorphous to crystalline phases decreases with increase in temperature. The surfaces of Al2O3 film grown using PLD was found very smooth with least root square roughness less than 2 nm.

Antidot arrays were formed in thin films of bismuth by the e-beam evaporation of the metal on the porous surface of porous anodic alumina templates. The magnetoresistance of the antidot array films was measured and compared to that of films deposited on glass slides. A significant difference in magnetoresistance behavior was observed, and this difference was attributed to the enhancement of the two dimensional weak antilocalization effect in the antidot arrays. Scattering rates were obtained by fitting the experimental results to the theoretical expression. The results indicate that the antidot morphology enhances the elastic scattering rate over the inelastic scattering rate.

With an average diameter of 80–200 nm, nylon fibers embedded with ferrite nanoparticles were electrospun using a point to plate geometry. The nickel-ferrite particles with a diameter range of 20–30 nm were used to prepare the composite electrospun nanofibers. The ferrite nanoparticles were dispersed in the polymer solution using a surfactant dodecyl benzene sulfonic acid (DBSA). Ultrasonication was used to dissolve nylon-6 into the formic acid/particle dispersion. Electrospinning of virgin polymer solution and particle filled polymer system was carried out with polymer concentration of 15% w/v. The particle loading was 3%w/w. SEM of the particle filled fibers show some bead formations and a diameter distribution of about 80–200 nm. The DSC analyses of the neat nylon polymer fibers and ferrite filled nanofibers show an increase in glass transition temperature from 55°C to 72°C. The melting temperature showed a decrease from 226°C to 201°C. The TEM images show the presence and some alignment of particles in the polymer. The electron diffraction pattern of ferrite nanoparticles confirms its crystalline nature.