Materials Literature
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New A-B type π-conjugated copolymers of N-alkylpyrroles and squaric acid have zwitterionic structure, analogous to squaraine dyes. These polymers are soluble in organic solvents, show solvent and pH-induced optical spectral changes, and are semiconducting.
A novel optical compensator with a negative birefringence structure is proposed to widen the viewing angle of twisted-nematic liquid-crystal displays (TN-LCDs). We describes the design concept and the simulation results to give a theoretical basis for the development of this new class of material. Computer simulation…
ESR spectra of oxochromium(V) porphyrins were obtained to investigate the electronic structure of the Cr(V)=O moiety. At room temperature, the chlorooxochromium(V) meso-tetramesitylporphyrin complex 1-Cl exhibits an isotropic ESR signal, split into nine signals due to hyperfine coupling with four equivalent( 14)N, at…
The crystal structure and absorption spectroscopy results of the Na(3)[Nd(TTHA)].2.5NaClO(4).7.617H(2)O compound are presented. The crystal structure of the complex was determined by X-ray analysis. Crystals are monoclinic, space group C2/c, with a = 38.446(8) Å, b = 10.552(2) Å, c = 25.796(5) Å, beta = 130.51(3) degr…
Treatment of (4-bromophenyl)diethoxymethylsilane with magnesium in THF gave poly[ p -(ethoxymethylsilylene)phenylene] ( 1a ) in 58% yield. Similar reactions of (4-bromophenyl)triethoxysilane and (3-bromophenyl)diethoxymethylsilane with magnesium afforded poly[ p -(diethoxysilylene)phenylene] ( 1b ) and poly[ m -(ethox…
The viability of using the reverse Monte Carlo (RMC) method for quantitative analysis of the diffuse X-ray or neutron scattering from single crystals of disordered materials is investigated. The method has been applied to a number of two- and three-dimensional model examples in which both occupational and displacement…
The human estrogen-related receptor �1 (hERR�1) is an orphan member of the steroid/thyroid hormone receptor superfamily. A cDNA encoding this protein was originally isolated on the basis of sequence similarity in its DNA-binding domain with estrogen receptor � (ER�). Previously, we reported the purification of hERR�1…
The concept of random first order transitions with configurational entropy crises provides a theoretical framework for understanding the glass transition. This paper discusses such transitions in exactly solvable spin glass models and in globular random heteropolymers and their relation to glass transitions in molecul…
Abstract We have developed a method for observing transverse swelling of cellulosic fibres in the environmental scanning electron microscope (ESEM). The presence of liquid water in the ESEM specimen chamber allows the observation of in situ hydration without the need for coating, freezing, or drying of the sample. For…
The synthesis of metalloporphyrin-oligonucleotide conjugates with different metalloporphyrin moieties are described as well as the comparison of their in vitro nuclease efficiency toward a single-stranded DNA target. Between cationic, anionic and hydrophobic manganese porphyrins covalently linked to the oligonucleotid…
Abstract The “in‐situ” compatibilization for a PET/LCP blend via transesterification reactions in a twin‐screw extruder having a very short residence time is investigated through thermal, rheological, and mechanical studies. Inclusion of a small amount of liquid crystalline polymer (LCP) enhanced the crystallization r…
A comprehensive experimental study on the late stages of phase separation in two dimensions was performed by phase separating thin (1.5 and 10 \ensuremath{\mu}m) films of off- and near-critical polymer solutions. The resulting domain-size growth rate (coarsening rate) of the dispersed phase was directly measured for s…
The environmental effects on the mechanical properties of fiber‐reinforced composites at intermediate temperatures were investigated by conducting flexural static‐fatigue experiments in air at 600° and 950°C. The material that was studied was a silicon carbide/boron nitride (SiC/BN) dual‐coated Nicalon‐fiber‐reinforce…
Abstract The reaction of manganese with antimony and sulfur in an aqueous ethylenediamine (en) solution under hydrothermal conditions gives Mn(en) 3 Sb 4 S 7 . The structure of the title compound consists of Mn(en) 3 2+ cations and infinite one-dimensional (Sb 4 S 7 2- )„ anions forming slabs via long secondary interc…
The deformation behavior of poly(ether ester) is studied by means of small- and wide-angle X-ray scattering (SAXS and WAXS). The material under investigation represents a polyblock thermoplastic elastomer of poly(ether ester) (PEE) type. It comprises poly(butylene terephthalate) (PBT) as hard segments and polyethylene…
We present a computer simulation study of the liquid-vapor interface of the Gay-Berne fluid model for a range of temperatures above and below the vapor-isotropic liquid-nematic triple point. The molecular elongation is \ensuremath{\kappa}=3, and two values of the energy anisotropy parameter (${\mathrm{\ensuremath{\kap…
The interaction between two plates coated by adsorbed polymer layers is considered theoretically in the marginal solvent regime. A novel mean-field approach that takes into account the effect of chain ends is proposed. The approach generalizes the well-known ground-state dominance theory. It is shown that the effect o…
Transesterification mechanisms and rate in blends of polycarbonate (PC) and random liquid crystalline polyester copoly(oxybenzoate− p -terephthalate) at molar ratio 40/60 (P46) were studied through a five-component diad analysis and with 13 C and 1 H− 13 C nuclear magnetic resonance spectroscopy. It was found that the…
The annealing of poly(aryl ether ether ketone) (PEEK) from the glassy state was investigated by time-resolved simultaneous small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron radiation and by differential scanning calorimetry (DSC). Each experiment consisted of a heating ramp from 100 °C to the…
Reaction-induced phase separation of polymer blends was examined by optical microscopy in this work. Four distinct types of ordering processes were observed when a miscible polymer blend was photo-cross-linked in the one-phase region located between the coexistence curve and the glass transition temperatures. These st…