Using a combination of x-ray diffraction, volumetric adsorption and inelastic neutron scattering (INS) the adsorption properties of methane within the channels of L-Isoleucyl-L-Valine (IV) and L-Valyl-L-Alanine (VA) dipeptides have been investigated. These biomaterials have quasi one-dimensional channels of tunable diameters in the range of 3-6 Å and offer possibilities for selective adsorption, as well as, water and gas transport properties. High-resolution volumetric methane adsorption measurements performed near 100K for IV find that this biomaterial exhibits an adsorption capacity of ∼100 m2/g. High-resolution Inelastic Neutron Scattering (INS) measurements were performed at the Spallation Neutron Source using the BASIS spectrometer with ∼ 3.5 μeV resolution. The data clearly indicate that at least two spectral features at energy transfers near 100 and 200 μeV are present, which suggests a lowering of the hindering potential for methane reorientation primarily about the three-fold axis within the IV channels. Such features play a key role in understanding details concerning the potential energy surface. These thermodynamic and INS studies suggest that the flexibility and dynamical motion within the dipeptide channels may play a significant role in the adsorption properties.

Silicon nanoparticles are synthesized by very high frequency Plasma Enhanced Chemical Vapor Deposition (vhf-PECVD) in the gas phase. Pulsed plasmas are used to obtain particles with a narrow size distribution. The role of plasma OFF times is studied to tailor the size of the silicon nanoparticles. Various plasma OFF times are chosen, both longer- and shorter -than the residence time of the gases in the discharge. Time resolved optical emission spectroscopy (TROES) studies provide additional information about the growth precursor dynamics during plasma modulation. The size and the size distribution studies of the particles are done with transmission electron microscopy (TEM). These studies reveal that a plasma OFF time longer than the residence time is favorable for the formation of quantum sized silicon particles.

This paper introduces a fabrication method to achieve sub-15 nm line-and-space (L/S) patterns by combining grapho- and chemo-epitaxy using poly(styrene-block-methyl methacrylate) copolymer (PS-b-PMMA). The fabrication method is simple, since it eliminates photoresist stripping and also does not require any special materials to form pinning patterns. In this process, the ridges formed on spin-on-glass (SOG) surface work as physical guides and the photoresists on them are utilized as a pinning layer. Fine PS-b-PMMA L/S patterns were obtained in sufficient critical dimension (CD) range of the guide patterns that corresponded to the 15% dose margin using ArF immersion lithography. 3-dimensional grid defects were found to be the origin of the short defects. The half-pitch (hp) 15 nm L/S patterns were transferred successfully to SOG/spin-on-carbon (SOC) stacked substrate.

We also describe fabrication of sub-10 nm L/S patterns using a high-chi block copolymer (BCP).

The demand for a stable and compatible redox shuttles for use in lithium-ion batteries has prompted us to explore strategies to tune and improve the properties of redox shuttles. We have studied over 50 new diarylamine derivatives synthesized in our laboratory including one compound in which we introduced trifluoromethyl groups (–CF3) at the positions para to the nitrogen atom in N-ethylphenothiazine (EPT). The high electronegativity of the CF3 group raises the oxidation potential, and its incorporation also significantly increases solubility in battery electrolyte. Here we report 3,7-bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) as a new redox shuttle, which we have observed to have the highest reported solubility in battery electrolyte of all redox shuttles that maintain extended overcharge performance. We have compared its performance with 1,3-di-tert-butyl-2,5-dimethoxybenzene (DBB), EPT, and other robust redox shuttles. In our hands, overcharge cycling of BCF3EPT far surpasses any reported redox shuttle, and – because it can be dissolved at higher concentrations – it tolerates faster charging rates than both DBB and EPT.

The addition of nanoparticles into polymeric materials has changed dramatically the properties of the host polymers, promising a novel class of composite materials with different properties and added functionalities. This research focuses on the influence of inorganic nanospheres particles such as SiO2, Al2O3, Fe2O3, TiO2 and nanoplatelets, such as Bentonite nanoclay, on the thermo-mechanical properties of a polyacrylic latex (utilized in commercial coatings). The analysis of the thermal and mechanical properties showed a decrease of Young's modulus and glass transition temperature T g in the presence of spherical nanoparticles. However, there was an increase of these properties in the presence of nanoplatelets (Bentonite), as demonstrated by the dynamic mechanical analysis and uniaxial tensile analysis. Moreover, water contact angle measurements demonstrated significant increase in hydrophobic behavior when incorporating nanosphere particles as compared to nanoplatelets. These results showed that the metallic oxides nanoparticles greatly influenced the physical and mechanical properties of the neat polyacrylic matrix.

Here we present a novel silicon nanopore planar patch clamp chip for single ion channel screening. We fabricate our devices using a combination of KOH and metal-assisted etching. Electrical characterization shows that the shunt capacitance and access resistance are within the accepted ranges for single channel recordings. In order to test our devices, we cultured and differentiated human neuroblastoma SH-SY5Y cells on chip. We reliably obtained a high resistance seal to the cell membrane and report single ion channel activity recordings.

It was established that at selective laser sintering of Al2O3 - Al compacted mixtures oxidation of the Al particles took place due to diffusion of oxygen into the volume of the workpieces. Depending on the content of aluminum, composite ceramics of various types were formed.

We developed a new soft-lithographic fabrication technique which enables the realization of high aspect-ratio PDMS micropillars. The key enabling factor is the adoption of the direct drawing technique incorporated with the in situ heating for simultaneous hardening and solidification of the PDMS micropillars. In addition, our technique allows self-aligned installation of highly reflective microspheres at the tips of the micropillars. Using the transparent PDMS micropillar as a flexible waveguide and the microsphere as a self-aligned reflector, we transformed the microsphere-tipped PDMS micropillars into all optically interrogated acoustic sensors inspired by the cricket’s filiform hairs and successfully demonstrated the sensing capability.

The Laser Intensity Modulation Method, LIMM, has been used to investigate the poling state of ceramic piezoelectric thin films. The frequency of the system has been extended to 70MHz to enable films of thicknesses down to 100nm to be measured. A unique development has been to sweep the DC bias applied to the sample whilst performing the LIMM measurement, thus giving pseudo PE loops. These PE loops are unique in that they represent the polarization state within a distinct depth of the film, whereas normally PE loops are a result of the complete film. This allows us to investigate processes occurring within different regions of the film.

Synthesis and understanding of metal oxide nanomaterials with improved electrochemical properties can play a big role in the development of high capacity electrochemical cells for application in lithium-ion batteries (LIBs). Metal oxide nanostructured materials have shown exceptional storage capabilities through conversion reaction. But, excess reversible capacity is usually observed in these systems. To understand the origin of the excess capacity, we have prepared nanostructured ruthenium oxide (RuO2) directly on stainless steel current collectors using low pressure chemical vapor deposition. The crystal structure of the as-prepared materials were examined by powder X-ray diffraction and indexed to the rutile structure. Field emission scanning electron microscopy revealed 3D pyramidal shape architectures that self-assembled into columns creating high surface area. Galvanostatic charge-discharge measurements were performed versus Li/Li+ in the range of 4.0 to 0.1 V. We have observed a reversible capacity of 1150 mAh/g which is equivalent to 5.70 Li per mol of RuO2. The expected capacity of RuO2 is 806 mAh/g which is approximately 4 Li per mol of RuO2 based on this equation: RuO2 + Li + 4e- ↔ Ru0 + 2Li2O. The excess capacity is approximately 435 mAh/g. The origin of the excess capacity was investigated using cyclic voltammetry, which was performed at two different range of voltage.

The vertical TiO2 nanotube arrays constituting the core of 3-D nanoscale electrode architecture were synthesized over Ti sheet by anodization. Such formed TiO2 nanotubes are electrically conducting and amorphous as confirmed by XRD studies. Nanotube morphology is affected by water content and in the present study, close-packed 3-4 μm long TiO2 nanotube arrays of 45-50 nm diameter are formed with 2% water as revealed by the transmission and scanning electron microscopy. The redox active polypyrrole sheath is created by ultra-short pulsed current electropolymerization. Electrochemical properties of the 3-D nanoscaled TiO2 nanotube core-polypyrrole sheath electrodes relevant to the energy storage were investigated using cyclic voltammetry (CV) plots, electrochemical impedance spectroscopy (EIS), Charge discharge (CD) tests. High areal capacitance density of 48 mF cm-2 and low charge transfer resistance 12 Ω cm-2 with least ion diffusion limitation are realized at optimized polypyrrole sheath thickness. The Raman spectra studies reveal anion at specific chain locations involve in the redox process.

This paper describes the characteristics of damage, introduced under different conditions of diamond wire sawing, on the Si wafer surfaces. The damage occurs in the form of frozen-in dislocations, phase changes, and microcracks. The in-depth damage was determined by conventional ways such as TEM, SEM and angle-polishing/defect-etching, which only provide local information. We have also applied a new technique based on sequential measurement of the minority carrier lifetime after etching thin layers from the surfaces to determine average damage depth and its in-depth distribution. The lateral spatial damage variations, which seem to be mainly related to wire reciprocation process, were observed by photoluminescence and lifetime mapping. Our results show a strong correlation of damage depth on the diamond grit size and wire usage.

Physicochemical effect on the corrosion process of AISI 1018 steel exposed to five type of soils from South of México at different moisture content using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves was studied. Two soils were collected in the state of Veracruz (clay of high plasticity and silt) and three soils from the state of Campeche (sand, clay and clay-silt). Moisture values were determined by addition of 0, 20, 40 and 60 ml of deionized water in a volume of 125 cm3 of each soil. The corrosion behavior of uncoated and coated steel with a viscoelastic polymer was analyzed. Effect of damage on the coating when the steel is exposed to corrosive soils was studied. EIS evaluations indicate that 1018 steel without coating is more susceptible to corrosion in the clay at the maximum moisture content (39.7 wt. %). However, for sand the more corrosive moisture belong to 12.8 wt. %, which is not the maximum moisture, which is agree with the lower polarization resistance (52.21 Ω.cm2). Potentiodynamic polarization curves suggested that uncoated steel exposed to clay-silt from state of Campeche exhibited the higher corrosion rate (0.698 mm/year) at 53.1 wt. % moisture. Meanwhile, in the coated steel with induced damage, the higher corrosion rate was obtained in the clay (0.0018 mm/year) at 34.2 wt. % moisture. 1018 steel coated with induced damage exposed to clay displayed the higher Ecorr values, which means that clay is more susceptible to overprotection as consequence of any change in the voltages originated by moisture content.

Materials with different allotropes can undergo one or more phase transformations based on the changes in the thermodynamic states. Each phase is stable in a certain temperature/pressure range and can possess different physical and mechanical properties compared to the other phases. The majority of material characterizations have been carried out for materials under equilibrium conditions where the material is stabilized in a certain phase and a lesser portion is devoted for onset of transformation. Alternatively, in situ measurements can be utilized to characterize materials while undergoing phase transformation. However, most of the in situ methods are aimed at measuring the physical properties such as dielectric constant, thermal/electrical conductivity and optical properties. Changes in material dimensions associated with phase transformation, makes direct measurement of the mechanical properties very challenging if not impossible. In this study a novel non-isothermal nanoindentation technique is introduced to directly measure the mechanical properties such as stiffness and creep compliance of a material at the phase transformation point. Single crystal ferroelectric triglycine sulfate (TGS) was synthetized and tested with this method using a temperature controlled nanoindentation instrument. The results reveal that the material, at the transformation point, exhibits structural instabilities such as negative stiffness and negative creep compliance which is in agreement with the findings of published works on the composites with ferroelectric inclusions.

We have demonstrated the synthesis of highly reactive boron nanomaterials by alkali metal reduction of BCl3 under sonication, followed by annealing. Unlike ordinary boron powders, these materials combust completely and release close to their theoretical energy content (based on elemental analysis) in polymer protected bomb calorimetry experiments. We have scaled up the synthesis using a commercial (Columbia International CIT-UHiPR-U1000V600) ultrasonic hi-pressure reactor. The synthesis reactions exhibit a scale problem, where they yield diminishes considerably on scale up, probably a result of alkali metals becoming trapped inside a mass of salts and rendered unable to react. We measured the combustion properties of the materials by bomb calorimetry, and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and report elemental analyses on selected samples.

The ternary system Fe - 25 at% Co - 9 at% Mo shows an age hardening behavior similar to aluminum alloys. After solution annealing followed by rapid quenching, the Fe-Co-matrix is hardened during subsequent aging through precipitation of the intermetallic µ-phase (Fe,Co)7Mo6. In aged condition the entire Mo content is present in coarse primary and fine µ-phase particles and, therefore, the matrix consists exclusively of 71 at% Fe and 29 at% Co. The binary system Fe-Co shows a transformation from the disordered bcc structure to the ordered B2 structure between 25 and 72 at% Co at a critical ordering temperature ranging from room temperature to 723°C. As a consequence, the remaining overaged matrix in the Fe - 25 at% Co - 9 at% Mo system should also show such a transition. However, an ordered phase is brittle and, thus, not wanted for many applications. Better mechanical properties in terms of ductility can be achieved with a partially or fully disordered phase. Such a state can be obtained by rapid quenching from temperatures above the critical ordering temperature. In this study such an approach was implemented on the ternary Fe - 25 at% Co - 9 at% Mo alloy. The effect of different cooling rates on the mechanical properties was investigated by means of hardness testing. The actual ordering transition of the Fe - 29 at% Co matrix was determined with differential scanning calorimetry and neutron diffraction.

We here present electronic structures and chiroptical responses of gold-based bimetallic nanoclusters protected by chiral thiolate ligand, glutathione (GSH), and compare them with those of monometallic counterparts. The nanoclusters examined are AuPd and AuAg bimetallic systems. The effect of Pd or Ag doping on the chiroptical responses of optically active Au nanoclusters as well as the importance of the bimetallic core configurations are discussed. Briefly, we find that GS-protected AuPd or AuAg nanoclusters exhibit quite different Cotton effects from those of the monometallic nanoclusters in metal-based electronic transition regions. In the AuPd system, all bimetallic nanoclusters exhibit featureless absorption profiles, but their circular dichroism (CD) signals are structured, offering a greater advantage in detecting a foreign atom doping in the nanocluster system. In the AuAg system, the nanocluster compounds exhibit relatively weaker CD responses than those of the corresponding Au compounds. This CD decrease can be explained in terms of the increased geometrical isomers that are formed by statistical distribution of Ag heteroatoms in the nanocluster, since an increased number of possible configurations gives an average in the CD response with positive and negative bands of different optical isomers.