Materials Literature
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We present experimental results on resonant spin tunnelling in a single crystal of Mn$_{12}$-2Cl benzoate with different concentration of dislocations. The time evolution of the magnetisation follows the stretched exponential over a few time decades. The values of parameters of stretched exponential deduced from exper…
Aromatic–aliphatic thermotropic liquid crystalline terpolyesters derived from 2,6-naphthalenedicarboxylic acid, hydroquinones, and 8-(3-hydroxyphenyl)octanoic acid (HPOA), a monomer with built-in kink and flexible moieties, were prepared by a melt polycondensation reaction. These polymers were characterized for their…
Polypyrrole (PPy) thin films were prepared electrochemically at a constant potential. Gas-sensing behaviors, including reproducibility, sensitivity, and response time to various benzene, toluene, ethylbenzene, and xylene (BTEX) compound concentrations, were investigated. BTEX compounds were found to be able to compens…
The solubilities of some ferrocenes (ferrocene, ferrocenylmethanol, and 1-ferrocenylethanol) in hexane, benzene, toluene, ethanol, 3-pentanone, and butyl methyl ether have been determined experimentally by a dynamic method at temperatures from (280 to 350) K. The results have been correlated by the Wilson and UNIQUAC…
Abstract The effect of different reaction conditions on the grafting of methyl methacrylate (MMA) onto guar gum (GG) has been studied in detail. The grafting efficiency was optimal under the following conditions: MMA at 1.13 mol/L; ceric ammonium sulfate at 6.32 × 10 −3 mol/L; dextrose monohydrate at 2.428 × 10 −3 mol…
Divergent synthesis methods have been used to prepare 2nd generation dendrimers based on polyhedral silsesquioxane cores with up to 72 terminal groups at their surface. Repetitive hydrosilation/allylation of vinyl-functionalised polyhedral silsesquioxanes produce chlorosilyl- and allyl-derivatised dendrimers respectiv…
Two types of multiporphyrin arrays, mediated by PdCl4(2-) complex ions at the air-water interface, were alternately transferred onto solid supports to form three-dimensional organized multilayers by a layer-by-layer method.
Abstract We report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the co…
Abstract Two series of novel phosphorus‐containing poly(alkylene) amines with or without aromatic groups were synthesized via reacting phosphoryl chloride derivatives with commercially available polyetheramines, ethylenediamine and N‐phenyl‐1,4‐phenylenediamine, respectively. Chemical structures of the amines were cha…
Dynamic secondary ion mass spectrometry was used to investigate the chain mobility of polystyrene (MW ranging from 4.3 to 957 kg/mol) at the free surface. The data show that the diffusion coefficient was reduced relative to the bulk value within a distance, d < or = 4R(g), from the surface and scaled as 1/N(2.5) at fi…
One of the simplest models describing the ion transport in disordered ionic conductors on a microscopic level is the random barrier model. Using Monte Carlo techniques, we simulate, for the first time, the low-temperature particle dynamics in random barrier model systems with long-range Coulomb interactions between th…
This paper deals with X-ray fluorescence (XRF), X-ray diffraction (XRD), and 29 Si nuclear magnetic resonance ( 29 Si NMR) measurements of rice husk silica treated under hydrothermal conditions in autoclave and steam-explosion processes. An understanding of the structural behavior of rice husk silica provides insight…
Abstract Poly(vinyl acetate) (PVAc) was added to the crystalline blends of poly(ethylene oxide) (PEO) and poly( L ‐lactide) (PLLA) (40/60) of higher molecular weights, whereas diblock and triblock poly(ethylene glycol)–poly( L ‐lactide) copolymers were added to the same blend of moderate molecular weights. The crystal…
The vibrational density of states (VDOS) of bulk nanocrystalline Ni and Cu (model) samples with grain diameters between 5 and 12 nm are derived from molecular-dynamics simulations. The results show an enhancement of the density of states at low and high energies. Because of large system sizes and a decomposition of th…
We show that adsorption of dye molecules control the light-induced alignment of dye-doped nematic liquid crystal (LC) on a nonphotosensitive polymer surface. The dependencies of light-induced twist structures on exposure, thermal baking, thickness, and aging before irradiation of the LC cells allowed us to propose the…
[structure--see text] As an attempt to rationally design organogelators, an amphiphilic porphyrin bearing four beta-D-galactopyranoside groups at its periphery was synthesized. This compound tends to aggregate in a one-dimensional direction, resulting in very robust gels in DMF/alcohol mixed solvents. Spectroscopic st…
Dynamics of thin films of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) have been investigated by dielectric relaxation spectroscopy in the frequency range from 0.1 Hz to 1 MHz at temperatures from 263 to 423 K. The alpha process, the key process of glass transition, is observed for thin films of PVA…
Abstract Polypropylene/clay (PP/clay) nanocomposites were synthesized via intercalative polymerization. The nanostructure of the composites was investigated by wide‐angle X‐ray diffractometry (WAXD) and transmission electron microscopy (TEM). The WAXD patterns of the PP/clay nanocomposites indicated that the character…
Raman spectra of the MgB2 ceramic samples were measured as a function of pressure up to 32 GPa at room temperature. The spectrum at normal conditions contains a very broad peak at ~590 cm-1 related to the E2g phonon mode. The frequency of this mode exhibits a strong linear dependence in the pressure region from 5 to 1…
The question addressed in this paper is that of the influence of the density of dislocations on the spin tunneling in Mn12 clusters. We have determined the variation in the mosaicity of the crystal structure of fresh and thermally treated single crystals of Mn12 by analyzing the widening of low angle X-ray diffraction…