Intercalation of Poly(bis-(methoxyethoxyethoxy)phosphazene) into Lithium Hectorite

Poly(bis-(methoxyethoxyethoxy)phosphazene) (MEEP) intercalated into lithium hectorite was investigated for its potential application as a solid polymer electrolyte in lithium-ion polymer batteries. Varying amounts of MEEP were intercalated into lithium hectorite, and the physical properties of the nanocomposites were monitored using powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and attenuated total reflectance spectroscopy. Alternating current (AC) impedance spectroscopy was used to determine the ionic conductivity of the nanocomposites when complexed with lithium triflate salt

Intercalation of Poly[Oligo(Ethylene Glycol) Oxalate] into Vanadium Pentoxide Xerogel: Preparation, Characterization and Conductivity Properties

We report, for the first time, the intercalation of poly[oligo(ethylene glycol) oxalate] (POEGO) and POEGO lithium salt (LiCF3SO3) complex (POEGO-LiCF3SO3) into vanadium pentoxide xerogel (V2O5nH2O). The effect of changing the polymer concentration on the interlayer expansion of the layered host was studied, and the optimal intercalation ratio was determined to be 1:2. The intercalates were characterized by powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, and AC impedance spectroscopy

Scanning Tunneling Microscopy Studies of Chloroplasts in Solution

Previous work has shown that it is possible to image whole uncoated chloroplasts using scanning tunneling microscopy (STM), provided this is done in solution using tunnelling currents below about 100 pA. More recent images include some which suggest that the STM is sensitive to dynamic processes occurring on chloroplast surfaces. Current-versus-distance curves and dI/ds measurements are consistent with tunnelling between the tip and sample surface, and relatively small deformations of the sample surface due to tip-sample forces. Attempts to use the same imaging conditions on bacteria were unsuccessful

Exfoliated Nanocomposites Based on Polyaniline and Tungsten Disulfide

Nanocomposite materials consisting of polyaniline (PANI) and exfoliated WS2 were synthesized. The WS2 was prepared by reacting tungstic acid with thiourea at 500°C under nitrogen flow. Samples were prepared with a WS2 content of 1, 5, 7.5, 10, 12.5, 15, 20, 37, and 64% by mass. An improvement in the electronic conductivity value of the PANI was observed through the incorporation of exfoliated WS2. The electronic conductivity of PANI-15%WS2 was 24.5 S/cm, an eightfold increase when compared to pure PANI. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) provided evidence that the nanocomposites are in an exfoliated state. XRD and TEM showed that the nanocomposites were completely amorphous, suggesting lack of structural order in these materials, while their EPR signals were considerably narrower compared to pure PANI, indicating the formation of genuine exfoliated systems. Furthermore, our research showed that WS2 can be used as a filler to improve activation energy of decomposition of the polymer. By using the Ozawa method, we studied the decomposition kinetics for the nanocomposites, as well as for the pure polymer. The activation energy for the decomposition of pure PANI was found to be 131.2 kJ/mol. Increasing the amount of WS2 to 12.5% in the PANI increases the activation energy of decomposition to 165.4 kJ/mol, an enhancement of 34.2 kJ/mol over the pure polymer

The substellar mass function in sigma Orionis. II. Optical, near-infrared and IRAC/Spitzer photometry of young cluster brown dwarfs and planetary-mass objects

We investigate the mass function in the substellar domain down to a few Jupiter masses in the young sigma Orionis open cluster (3+/-2 Ma, d = 360^+70_-60 pc). We have performed a deep IJ-band search, covering an area of 790 arcmin^2 close to the cluster centre. This survey was complemented with an infrared follow-up in the HKs- and Spitzer 3.6-8.0 mum-bands. Using colour-magnitude diagrams, we have selected 49 candidate cluster members in the magnitude interval 16.1 mag < I < 23.0 mag. Accounting for flux excesses at 8.0 mum and previously known spectral features of youth, 30 objects are bona fide cluster members. Four are first identified from our optical-near infrared data. Eleven have most probable masses below the deuterium burning limit and are classified as planetary-mass object candidates. The slope of the substellar mass spectrum (Delta N / Delta M = a M^-alpha) in the mass interval 0.11 Msol M < 0.006 Msol is alpha = +0.6+/-0.2. Any opacity mass-limit, if these objects form via fragmentation, may lie below 0.006 Msol. The frequency of sigma Orionis brown dwarfs with circumsubstellar discs is 47+/-15 %. The continuity in the mass function and in the frequency of discs suggests that very low-mass stars and substellar objects, even below the deuterium-burning mass limit, may share the same formation mechanism.Comment: Accepted for publication in A&A (12/04/2007). It has not been edited for language ye

07/222,623 1,298,416 H01J 37/00 (2006.01) H01L 41/09 (2006.01) Canada

A novel scanning tunneling microscope (STM) is described which is constructed almost entirely of one metal e.g. aluminum and uses bimorph piezoelectric disks as the x, y, z drive elements. The design uses a simple, rugged tripod configuration for the fine motion drive arms. Coarse motion of the sample, which is mounted on an aluminum holder, is achieved by pushing, or pulling, with a piezoelectric louse. Differential thermal expansion effects are avoided by design, to first order,and the resulting drift is ? 0.5 .ANG. per minute after only a short warm-up period. It is easy to build and operate, and has good immunity to mechanical vibration

222,623 4,894,537 Ho1J 37/00 H01L 41/09 (20060101) United States

A novel scanning tunneling microscope (STM) is described which is constructed almost entirely of one metal e.g. aluminum and uses bimorph piezoelectric disks as the x, y, z drive elements. The design uses a simple, rugged tirpod configuration for the fine motion drive arms. Coarse motion of the sample, which is mounted on an aluminum holder, is achieved by pushing, or pulling, with a piezoelectric louse. Differential thermal expansion effects are avoided by design, to first order, and the resulting drift is .ltoreq.0.5 .ANG. per minute after only a short warm-up period. It is easy to build and operate, and has good immunity to mechanical vibrations

Synthesis and characterization of poly(ethylene glycol amine) electrolytes and nanocomposites based on graphite

Poly(ethylene glycol) functionalized with an amino group (PEG-amine) was synthesized and characterized by proton NMR and FTIR spectroscopy. The polymer was complexed with lithium triflate (LiOTf) in varying ratios, and it was found that the composition (PEG-amine)8.0LiOTf exhibited a maximum ionic conductivity of 10−5 S/cm at a temperature of 320 K. Graphite platelets were also dispersed into the polymer matrix, and the resulting nanomaterials were shown to be electrically conductive, with a maximum value of 1 × 103 S/cm when the graphite is present at 50% by mass

A bilayer insertion of poly(oxymethylene-oxyethylene) into vanadium pentoxide xerogel

We report a method for inserting poly(oxymethylene-oxyethylene) (POMOE) and LiCF3SO3-POMOE (Li-POMOE) complex into V2O5nH2O xerogel at room temperature leading to a bilayer arrangement of the POMOE-chains within the gallery spaces. This could be a significant step towards developing improved electrolyte/cathode materials for lithium/Li-ion batteries. A series of intercalates were prepared to study the effect of changing the polymer concentration on the interlayer expansion of the layered host, and to determine the optimal insertion ratio. An insertion reaction mechanism is proposed. A hydrogen-bonding network between the polymer and the V2O5 framework contributes significantly to the formation of the nanocomposites. The nanocomposites showed reversible color change from red to green when subjected to electrical stimuli, thus making them good candidates for electrochromic devices. The materials were characterized by powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, and impedance spectroscopy