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In this paper, we report on a high‐throughput (gram quantities) solvothermal method for the synthesis of copper terephthalate metal–organic frameworks in dmf. While the structure of MOF‐2 and some of the associated polymorphs are well known, we know of no equivalent structural studies for the isostructural copper terephthalate (Cu–tpa). The material we have made crystallizes in the C2/m space group. Cu–tpa also exhibits reversible solvent‐exchange properties. These properties make this material useful for potential applications in gas storage and catalysis applications. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

The "grain-boundary effect," which leads to a greatly reduced dc ionic conductivity due to the presence of a blocking layer in the vicinity of the grain boundaries, is studied in detail for ceria ceramics doped with various trivalent dopants (particularly Y3+, Gd3+, and La3+). The effects of porosity, of sintering time, and of dopant size and dopant concentration are investigated. Finally, it is shown that the grain-boundary effect virtually disappears when nearly silicon-free starting materials are used.

Poly(methyl methacrylate) (PMMA)/carbon black (CB) composites were fabricated using two different mixing methods: (1) mechanical mixing and (2) solution mixing of the precursors, followed by compression molding. The microstructures obtained were examined by optical and scanning electron microscopy. Electrical properties were measured using impedance spectroscopy over a wide frequency range (10(-3) to +10(9) Hz). With the mechanical mixing method, a segregated structure is produced with PMMA particles forming faceted grains with carbon black particles aligning to form a network of 3D-interconnected nanowires. This microstructure allows percolation to occur at a low volume fraction of 0.26 vol % CB. In contrast, specimens made by the solution method have a microstructure where carbon black is distributed more randomly throughout the bulk, and thus, the percolation threshold is higher (2.7 vol % CB). The electrical properties of the PMMA/CB composites fabricated by the mechanical mixing method are comparable to those obtained with single-wall nanotubes as fillers.

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Poly (vinylidene fluoride) (PVDF) matrix hybrid nanocomposites, featuring ferroelectric barium titanate (BT) nanoparticles and multi-walled carbon nanotubes (MWCNT) embedded in the polymer, were fabricated by a miscible-immiscible coagulation method followed by hot pressing. SEM images showed good distribution of the ceramic nanoparticles with very little particle agglomeration. The conductive MWCNT increased the charge storage ability of the matrix polymer by serving as a polarized charge transport phase for the ferroelectric nanoparticles, while the small MWNT amounts used prevented the formation of conductive networks. The simple processing method utilized resulted in composites with high real permittivity and low dielectric loss over a wide range of frequency (10 Hz to 1 MHz). The dielectric properties of the polymer matrix nanocomposites with hybrid fillers (BT with and without MWNT) were improved by optimizing the synergistic effects between the charge storage behavior of the ferroelectric phase and the charge transport behavior of the conductive phase. The best combination of real permittivity and dielectric loss properties (71.7 and 0.045 respectively) were obtained for the nanocomposites containing 37.1 vol % of BaTiO 3 and 3 vol % of MWCNT. In addition to achieving reliable dielectric properties, the nanocomposites also displayed flexibility making these composites potentially useful for many flexible electronic devices and electrostatic energy storage devices.

In the synthesis of the microporous metal-organic framework copper 1,4-benzenedicarboxylate [Cu(BDC)], solvent exchange with methanol prior to recrystallization lowers the desolvation temperature to 160°C and produces more crystalline Cu(BDC). The solution to the crystal structure of Cu(BDC) has been determined by using ab initio quantum molecular calculations and refinement with synchrotron Xray powder diffraction data. This solution is in the P1 space group with a = 5.25 Å, b = 9.67 Å, c = 10.77 Å, α = 90.29°, β = 91.06°, γ = 92.413°, and V = 546.04 Å 3 . The Brunauer-

Poly(methyl methacrylate) (PMMA)/indium tin oxide (ITO) nanocomposites were prepared by mechanical mixing and compression molding in order to study the properties and microstructure of the composites. The composites were examined by optical and scanning electron microscopy, impedance spectroscopy, and UV‐VIS spectrophotometry. It was observed that upon compaction of the powders above the glass‐transition temperature of the matrix, the PMMA transforms from spherical to polyhedral‐shaped, and develops sharp edges and flat faces. The ITO nanoparticles do not penetrate the polymer particles, resulting in a novel segregated network microstructure. Excellent correlation between the electrical, optical, and microscopy data also provide good insight about the behavior of the filler as the content is increased in the nanocomposites. There is strong evidence that the ITO nanoparticles are extensively displaced during compaction as the PMMA powders become polyhedral‐shaped. Our results indicate that percolation occurs due to the ITO forming a continuous network along the edges of the faceted PMMA particles. The ITO nanoparticles do not appear on the faces of the PMMA particles until after a percolation path has formed and a marked increase in electrical conductivity has occurred. This behavior significantly diverges from previous models for segregated network microstructures which proposed that percolation occurred as the result of limited displacement of the filler during compaction of the mixed powders.