Materials Literature
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Polystyrene-block-poly(4-vinylpyridine) with nominally one pentadecylphenol molecule hydrogen-bonded to each pyridine group has been electrospun, leading to fibers with a hierarchical, structure-within-structure morphology (see Figure). An internal structure on the nanometer length scale exists within a structure on t…
Low-temperature hydrothermal techniques were used to synthesize single crystals of Ag(4)V(2)O(6)F(2). This previously unreported oxide fluoride phase was characterized by single-crystal X-ray diffraction and IR spectroscopy and was also evaluated as a primary lithium battery cathode. Crystal data: monoclinic, space gr…
We have investigated the influence of nickel doping in a series of n-type CoSb3 skutterudite materials partially filled with Ca. The electrical resistivity, thermopower, and thermal conductivity have been measured in the 300–800 K temperature range on CayCo1−xNixSb12 compounds prepared by a powder metallurgy route. Th…
The oxidation reaction of M(tpfc) [M = Mn or Cr and tpfc = tris(pentafluorophenyl)corrole] with aryl azides under photolytic or thermal conditions gives the first examples of mononuclear imido complexes of manganese(V) and chromium(V). These complexes have been characterized by NMR, mass spectrometry, UV-vis, EPR, ele…
The relaxation dynamics of water-rich glycerol-water mixtures is studied by broadband dielectric spectroscopy (BDS) at 173-323 K and differential scanning calorimetry (DSC) at 138-313 K. These data indicate the existence of the critical concentration of 40 mol % glycerol. In the studied temperature range for water-ric…
Optomechanical actuation of polymer films doped with spiropyran photochromic molecules is demonstrated by the reversible bending of the films upon laser irradiation (see Figure). The photoactuators are fully wavelength controllable and capable of operating reversibly in a few seconds. The reversible macroscopic mechan…
1. Lyotropic systems: main experimental facts and techniques 2. Basic concepts of phase transitions 3. Phase diagrams of lyotropic mixtures 4. Phase transitions between periodically organized lyotropic phases 5. The isotropic micellar and bicontinuous phases 6. The nematic and cholesteric phases 7. The lyotropic one-,…
Bimetallic Ag/Au prisms (Figure, top) and corrugated core-shell nanoparticles (Figure, bottom) are synthesized using seed-mediated growth. The sizes and shapes of these core–shell nanoparticles are tailored by varying the stoichiometric Au3+/Ag+ ratio. Decreasing Au3+/Ag+ ratio results in nanoparticles with thicker go…
Novel silica tube/polyimide (ST/PI) composite films prepared via ultrasonic dispersion and in-situ polymerization using STs (see Figure) from self-assembly and a PI precursor with N,N-dimethylacetamide as a solvent are reported. Dielectric constants significantly lower than that of the matrix are obtained. Effective m…
Single-walled carbon nanotube/ polyethyleneimine (SWNT/PEI) composite fibers are fabricated by coagulation-based spinning of SWNTs dispersed in aqueous solution by various surfactants. The spun SWNT/PEI composite fibers are either solid or hollow (see Figure), and have useful mechanical properties and over a hundred t…
The bending mechanics of singly bonded colloidal aggregates are measured using laser tweezers. We find that the colloidal bonds are capable of supporting significant torques, providing a direct measurement of the tangential interactions between particles. A critical bending moment marks the limit of linear bending ela…
Ultrananocrystalline diamond (UNCD) may offer a solution to tribological failure of silicon-based micromachines because of its outstanding mechanical properties. The first measurements of nanometer-scale adhesion and friction on the tribologically relevant underside of UNCD films (see Figure) are reported, revealing t…
The dielectric behavior of ferroelectromagnetic Pb(Fe1∕2Nb1∕2)O3 ceramics obtained using the traditional ceramic method employing three different precursors was investigated by impedance spectroscopy in the temperature range of 200–300°C. This study was carried out by means of the simultaneous analysis of the complex…
Polarization-resolved hyper Rayleigh scattering experiments were performed on gold metallic nanoparticles. These results unambiguously indicate that the second harmonic generation process of a nanoparticle is of pure electric dipole origin for the smallest particles as opposed to pure electric quadrupole, and that ret…
In the present work efforts have been made to investigate the influence of ac aging on space-charge dynamics in low-density polyethylene (LDPE). LDPE films with 200 μm were aged under various electric stress levels at 50 Hz for various times at ambient temperature. Space-charge dynamics in the samples after aging were…
By using rattan palm as a biotemplate, highly porous, α-Al2O3 ceramics with uniaxially directed porosity are produced via aluminum-vapor infiltration and subsequent oxidation in air. The high-strength ceramics retain the microstructural features of the palm (see Figure), and could be used as structural supports in cat…
A study of crack patterns in laponite films of different thickness is presented. Two cracking regimes are observed. The earlier with a higher rate of desiccation and shrinking has predominantly four-fold vertices in the crack network, while the later regime has less volume shrinking and forms mainly three-fold vertice…
Our previously defined Sparkle model (Inorg. Chem. 2004, 43, 2346) has been reparameterized for Eu(III) as well as newly parameterized for Gd(III) and Tb(III). The parameterizations have been carried out in a much more extensive manner, aimed at producing a new, more accurate model called Sparkle/AM1, mainly for the v…
We report the growth of epitaxial molybdenum oxide (MoOx,2<x<2.75) films on c plane of sapphire substrate using pulsed laser deposition in oxygen environment. The structure was characterized using x-ray diffraction, high resolution transmission electron microscopy and x-ray photoelectron spectroscopy (XP…
We report on the phonon dynamics of LiYF4 obtained by direct method using first principle calculations. The agreement between experimental and calculated modes is satisfactory. An inversion between two Raman active modes is noticed compared to inelastic neutron scattering and Raman measurements. The atomic displacemen…