Using a hybrid computational approach, we introduce A-like nanorods into a phaseseparating AB blend, which has 45/55 composition. In the absence of the rods, the minority A phase forms droplets in the matrix of B. With the addition of N = 670 rods that interact solely through a short range repulsive interaction (mimicking the steric stabilization provided by a coating of A ligands), the mixture retains this droplet morphology. When, however, we add an effective attraction between the sterically stabilized rods, the nanoparticles form extensive networks in the A phase, which can form a continuous phase. In addition to altering the morphology of the mixture, the attractive interaction influences the rate of domain growth. In particular, at early times, the mutually attractive rods increase the growth rate of the domains in the early stage. At late times, the domain growth crosses over to a slow growth regime. Our findings demonstrate that the morphology and coarsening of a rod-filled blend can be controlled by varying the rod-rod interaction and hence, provides guidelines for tailoring the electrical and mechanical properties of the nanocomposites.

1-3 BaTiO3-PVDF hybrid nanocomposites were prepared by combining electrospinning, sol-gel and spin-coating techniques. First, one-dimensional structures of barium titanate (BaTiO3) were obtained by electrospinning. An alcoholic solution consisting of Ba2+ and Ti4+ions (1:1 molar ratio) and poly(vinylpyrrolidone) was electrospun at 15 kV, with a tip-to-collector distance of 15 cm and a feed rate of 0.5 mL/h. Ceramic fibers were obtained after sintering the as-spun fibers at 900 °C for 2 hours. In a second step, poly(vinylidene fluoride) (PVDF) was incorporated to the oxide fibers by spin-coating a dimetilformamide solution, thus conforming 1-3 ceramic-polymeric hybrid nanocomposites on stainless steel substrates.

Scanning electron microscopy images showed that the as-spun fibers were smooth, long and continuous with an average diameter of 155 ± 40 nm, ranging from 60 to 240 nm, while sintered fibers presented a reduction in size, with an average diameter of 115 ± 16 nm, ranging from 96 to 120 nm. Sintered nanofibers were also long and continuous but with a rough surface. X-ray diffraction confirmed the perovskite-type structure of the BaTiO3. A structure refinement revealed a degree of tetragonality of 1.0046.

The polymer crystalline phases were identified by infrared spectroscopy on ATR mode. This study showed the presence of both β and γ polar phases, and absence of non-polar α phase, according to the characteristic bands for such crystalline phases.

The nanocomposites exhibited a ferroelectric behavior and electrical polarization according to their ceramic and polymeric components.

We present an investigation of the degree of oxidization of tungsten oxide (WOx ) thin films used as gate dielectric for metal-insulator-semiconductor field-effect transistors (MISFET). By means of X-ray photoelectron spectroscopy WOx thin films grown by pulsed-laser deposition at room temperature were investigated. The electrical and optical properties depend significantly on the oxygen pressure during deposition and are affected by the stoichiometric ratio of oxygen and tungsten.

The Lambertian limit represents a benchmark for the enhancement of the effective path length in solar cells, which is important as soon as the absorption length exceeds the absorber thickness. In previous publications it has been shown that either extremely thick or extremely thin solar cells can be driven close to this limit by exploiting up to date photon management. In this contribution we show that the Lambertian limit can also be achieved with thin-film solar cells based on amorphous silicon for practically relevant absorber thicknesses. Departing from superstrates, which are currently incorporated into state-of-the-art thin-film solar cells, we show that their topology has simply to be downscaled to typical feature sizes of about 100 nm in order to achieve this goal. By systematically studying the impact of the modulation height and the lateral feature sizes of the incorporated textures and of the absorber thickness we are able to deduce intuitive guidelines how to approach the Lambertian limit in randomly textured thin-film solar cells.

We report the growth of silicon nanowires by plasma assisted metal organic chemical vapor deposition. Silicon nanowires grew as three-dimensional networks in which electrical charges and heat can travel over the distance much longer than the mean length of the constituent nanowires. We studied the dependence of thermoelectric properties on two factors; nominal doping concentrations and geometrical factors within the silicon nanowire networks. The silicon nanowire networks show Seebeck coefficients comparable with that of bulk silicon for a given nominal doping concentration, allowing us to control Seebeck coefficients by tuning the doping concentrations. Rather than studying single nanowires, we chose networks of nanowires formed densely across large areas required for large scale production. We also studied the role played by intersections where multiple nanowires were fused to form the nanowire networks. Structural analysis, transport measurement, and modeling based on finite-element analysis were carried out to obtain insights of physical properties at the intersections. Understanding these physical properties of three-dimensional nanowire networks will advance the development of thermoelectric devices.

Copper oxide (CuO) and zinc oxide (ZnO) nanostructures complement each other since CuO is unintentional p-type and ZnO unintentional n-type. Using the low temperature chemical growth approach, the effect on morphology of varying the pH of the grown ZnO nanostructures and CuO micro structures is monitored. For both materials the variation of the pH was found to lead to a large variation on the morphology achieved. The grown ZnO NRs and CuO micro flowers material were used to fabricate devices. We demonstrate results from ZnO nanorods (NRs)/polymer p-n hybrid heterojunctions chemically grown on paper and using a process on paper for light emitting diodes (LEDs) applications as well as some large area light emitting diodes LEDs. The growth of CuO micro flowers indicated good quality material for sensing applications. The grown CuO micro flowers were employed as pH sensors. The results indicated a superior performance as expect due to the catalytic properties of this material.

Aluminum-doped zinc oxide (ZnOx:Al) films have been deposited on a moving glass substrate by a high throughput metalorganic chemical vapor deposition process at atmospheric pressure. Thin (< 250 nm) ZnOx:Al films have a poor crystalline quality, due to a small grain size and the presence of different crystallographic orientations. The crystalline quality improves with increasing film thickness (from 50 nm to 1000 nm), resulting in a lower value of resistivity (from 100 Ohm cm to 1·10-3 Ohm cm, respectively). We have investigated the variation in the films’ conductivity and transparency induced by a post-deposition exposure to a He/H2 atmospheric plasma. The resistivity of thin (< 250 nm) films is found to decreased sharply from 100 Ohm cm to about 4·10-3 Ohm cm by a short (∼ seconds) plasma exposure, while the resistivity of thicker films remains unaffected.

Two types of porous materials derived from emulsion templates are described as potential scaffolds for tissue engineering. Novel oil-in-water particle stabilised, Pickering High Internal Phase Emulsions (HIPE) stabilised with hydroxyapatite (HAp) nanoparticles were prepared and polymerised to form stable polyHIPEs. By adding a water soluble glycidyl methacrylate (GMA) derivatised dextran as monomer to the continuous aqueous phase of the HIPEs, these Pickering-HIPEs stabilised by nontoxic biocompatible HAp nanoparticles, can be used as templates to manufacture interconnected high porosity macroporous hydrogels. A second type of emulsion templated “poly”HIPE was prepared without the need for covalent crosslinking chemistry which was replaced by a thermally-induced non-covalent scaffold forming process (thermoHIPE). These scaffolds form close to body temperature and potentially offer a new approach to the formation of injectable scaffolds for tissue engineering.

In this work TiO2/Si multilayer structures have been grown by sputtering. After rapid thermal annealing in pure inert gas or inert gas with oxygen atmosphere the multilayers have been investigated by high resolution transmission electron microscopy, μ-Raman and dynamic secondary ion mass spectrometry for their structure and anatase/rutile phase composition. It has been found that the photocatalytically more active anatase TiO2 is stabilized and that interdiffusion and chemical reaction processes were strongly hindered up to 1100°C annealing temperature in oxygen containing atmosphere. These findings are of particular importance since only at this high temperature simultaneous formation of embedded Si nanocrystallites can be achieved.

The experimental investigation of actinide materials like nuclear fuels is difficult and usually very costly. Therefore a reliable multi-scale modeling of these often hazardous materials starting at the atomistic level is inevitable to gain further insight into this type of materials. The development of new, more advanced simulation methods accompanied by the rapid growth of the available computational resources provided by high-performance computing facilities, allows the modeling of such materials at a new quality level. Also the recent development of the CP2K program package (http://www.cp2k.org) has been partially focused on enabling state-of-the-art simulations of actinide materials using classical potential as well as electronic structure methods. The long-term goal is to perform reliable molecular dynamics simulations for actinide materials including advanced simulation techniques like nudged elastic band or metadynamics simulations. In this work, the CP2K program package and its application to the simulation of defect migration in uranium dioxide (UO2) using the nudged elastic band method is presented.

The goal of this research was to investigate the ability of lubricin to prevent bio-fouling of intraocular lenses after surgery, through surface coating trials with lubricin and analogues of the two major sub-units of the lubricin molecule (mucin and vitronectin). Yearly, there are over 6 million surgeries worldwide that involve intraocular lenses (IOLs) 1. However, preventing post-operative biofouling and bacterial infection of these implants remains a challenge 2. Surface modification of IOLs may provide a solution. This study proposes the use of the anti-adhesive protein lubricin (LUB), a glycoprotein found in the synovial fluid, as a means to make polymer surfaces less prone to bacterial adhesion and proliferation; thus, reducing the opportunity for post-operative infection 3. This study used extended bacteria growth trials on tissue cultures polystyrene coated with either lubricin, vitronectin, or mucin to investigate how lubricin and protein sub-regions of lubricin may reduce bacterial adhesion and proliferation.

The trend to manufacture components reduced in size at the micro- and nano-scale is obvious and is becoming more and more the state of art in designing actuators, sensors and chips. In recent years, nanoscale fabrication has developed considerably, but the fabrication of freestanding nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer to get specific geometries such as discs and more complex components such as gears and wheels in the near future. The almost cubic particles are essentially defect-free, therefore, provide very high strength (σ>2500MPa) in combination with excellent formability (|ϕ|>1,6). There are two approaches for forming these small particles. Upset forging is used to forge small discs (height<100nm) and to shape the nanoparticle in specific areas. Press forging into nano-dies is used to forge more complex structures. In this way free-standing, high-strength, metallic nanoobjects may be shaped into components with dimensions in the 100 nm range. By assembling such nano-components, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).

The necessity of studying cultural heritage through non-invasive and non-destructive techniques has led to significant advances in the last decade. One of the most recent advancements in this theme in Mexico is the portable X-ray system SANDRA, which was used to study three manuscripts directly related to the history of “San Nicolás Coatepec”, Mexico. X-ray fluorescence was chosen as the suitable technique because it can provide a fast qualitative and quantitative multielemental high sensitivity analysis. The documents were examined globally, using imaging techniques with UV and IR lighting. This research evinced a change in the composition and evolution of writing materials (inks and pigments) and provided information concerning historical use of the documents and its actual legal value as a property document. It also stressed the need of spanning these results to an extensive research attaining other regions of Mexico, in order to fully understand the Mexican documents particularities, aging and deterioration. This, in turn, will provide not only historical material information but also an invaluable scoop to understand deterioration and conservation issues.

Oxidation dynamics of three different sizes (26, 36 and 46 nm) of single aluminum nanoparticle (ANP) in oxygen environment are studied using multimillion-atom reactive molecular dynamics simulations. In the simulation, each aluminum nanoparticle is coated with an amorphous alumina shell of the same thickness (3 nm), and is ignited by heating the nanoparticle to 1100 K. The metallic aluminum and ceramic alumina are modeled by the Voter- Chen embedded atom model and the interatomic potential by Vashishta et al., respectively. Energy release rate and atomistic-level details of combustion of these single aluminum nanoparticles are investigated, along with the effect of nanoparticle size. The onset temperature of shell Al ejection is found to be independent of the ANP size, whereas the onset time of ejection and the time delay to the highest temperature change rate dT/dt depend on the size.

Thorium phosphate diphosphate Th4(PO4)4P2O7 (β-TPD) was already proposed for plutonium and minor actinides immobilization. Synthesis of Th4-xPux(PO4)4P2O7 with x∼1.5 corresponding to roughly 26 wt % of Pu was achieved demonstrating the thermodynamic stability of this phosphate-based material even for high plutonium mole loadings. We established reliable inter-atomic potentials in the shell-model approach for the β-TPD in order to calculate the Frenkel defects formation energies as well as the threshold displacement energies. Furthermore we carried out a detailed analysis of the energetic pathways for the corresponding Frenkel defects annealing. We deduced that the diphosphate sub-lattices may be easily displaced while the annealing mechanisms are revealed to be complex requiring highly energetic pathways, thus constituting the main defects configurations that may lead to the amorphous state.

Boron Phosphide (BP) is a promising material for use as a room temperature semiconductor detector of thermal neutrons. The absorption of a thermal neutron by a 10B nucleus in BP can yield 2.3MeV of energy which in solid state BP can yield ∼0.5 million electron-hole pairs that would be detectable with minimal amplification in a device. BP thin films are grown according to the net reaction below in a cold wall chemical vapor deposition (CVD) reactor: Thin film depositions are performed using diborane and phosphine with a balance of hydrogen gas at near atmospheric pressure with RF induction heating. The resultant BP films are characterized by Raman, XRD, SEM, TEM and TEM-EELS for chemical composition, surface and bulk morphology. BP growths on Si and SiC substrates are compared. SiC provides reduced lattice mismatch for growth of BP and growth of heteroepitaxial BP on SiC will be discussed.

In the ancient city of Cantona (600 B.C a 1050 A.D.) in the region of Puebla, Mexico, a great number of awls made of animal bones were found inside several offerings and burials. The present paper presents the identification of species used to elaborate these awls, along with the formal characteristics of the objects and their manufacturing techniques. The last was studied through experimental archaeology and the analysis of modified traces by Scanning Electron Microscopy (SEM).

A 60 GHz tandem coupler using offset broadside coupled lines is proposed in a WLP (Wafer Level Packaging) technology. The fabricated coupler has a core chip area of 750 μm × 385 μm (0.288 mm2). The measured results show an insertion loss of 0.44 dB, an amplitude imbalance of 0.03 dB and a phase difference of 87.6° at 60 GHz. Also the measurement shows an insertion loss of less than 0.67 dB, an amplitude imbalance of less than 0.31 dB, a phase error of less than 3.7°, an isolation of more than 29.7 dB and a return loss of more than 27.9 dB at the input ant coupled ports and more than 14.3 dB at the direct and isolated ports over the frequency band of 57-66 GHz, covering 60 GHz band both in Japan and US. To the best of our knowledge the proposed coupler achieves the lowest ever reported insertion loss and amplitude imbalance for a 3-dB coupler on a silicon substrate. With its superior performance and lower cost compared to the CMOS counterparts, the proposed coupler is a suitable candidate for low-cost high-performance millimeter-wave systems.