Materials Literature
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Two simple examples of spontaneous chiral symmetry breaking are presented. The first is close-packed cylindrically confined spheres. As the cylinder diameter is varied, one obtains a variety of chiral phases. The second example involves unconfined dipolar particles with an isotropic attraction, which also exhibits chi…
The nuclear magnetic relaxation in scandium metal is investigated at liquid helium temeprature for both single crystal and powder samples. The obtained temperature and field dependence of the Korringa constant are described by the means of the spin uctuation theory. It is shown that one of the reason for the high fiel…
The basic properties of point defects (atomic geometry, the position of charge-transfer levels, and formation energies) on the (110) surface of GaAs, GaP, and InP have been calculated employing density-functional theory. Based on these results we discuss the electronic properties of surface defects, defect segregation…
La 1−x Sr x CuOS (x=0, 0.05) thin films prepared by radio-frequency sputtering were found to have high optical transmission (⩾70%) at the visible and near-infrared wavelengths and an energy gap of about 3.1 eV. The dc electrical conductivities of x=0 and 0.05 thin films at room temperature were 1.2×10−2 and 2.6×10−1 S…
The nucleation and growth of aligned multiwall carbon nanotubes by microwave plasma-enhanced chemical vapor deposition have been studied. The nanotubes nucleate and grow from catalytic cobalt islands on a silicon substrate surface, with both their diameter and length dependent on the size of the cobalt islands. Electr…
The behavior of a grafted polymer chain confined in a tube is investigated within a scaling theory substantiated with biased Monte Carlo simulations of a self-avoiding walk (SAW) on a cubic lattice. All the statistical and thermodynamic properties of the chain follow from the knowledge of the joint distribution P(z,m)…
Phase behavior data are presented for poly( l -lactide) (L-PLA: MW = 2000 g·mol - 1 ), a biodegradable polymer, in supercritical solvent mixtures of carbon dioxide (CO 2 ) and chlorodifluoromethane (HCFC-22). Experimental cloud point curves, which were the phase boundaries between single and liquid−liquid phases, were…
A series of sterically demanding diporphyrins H2(por)-X-(por)H2 ligands that contain spacers (X) with different degrees of flexibility were synthesized from the trimesitylporphyrin derivatives 5-(4-hydroxyphenyl)-10,15,20-trimesitylporphyrin (TMP-OH)H2 (1a) and 5-(2,6-dimethyl-4-hydroxyphenyl)-10,15,20-trimesityl-porp…
T-junction grain boundaries were studied in a blend of polyisoprene homopolymer and a single graft block copolymer I 2 S with two equal length blocks of polyisoprene and one arm of polystyrene linked at a common junction point. The overall polyisoprene volume fraction in the blend was 0.52, and its equilibrium morphol…
The potentiostatic synthesis and microgravimetric kinetics of hybrid materials polypyrrole/PW 12 O 40 3- has been investigated. Every electrogenerated film was controlled by cyclic voltammetry. Charge consumed during polymerization, weight of the electrogenerated films, charge stored in the film, weight of the film af…
Inclusion complexes of self-assembled molecular dimers composed of two tetratolylurea calix[4]arenes show strongly different kinetic stability for different guests. In cyclohexane-d(12), half-life times for the exchange of a guest against the solvent vary from 2.9 h (chloroform) through 20 h (benzene) and 74 h (fluoro…
The phase-ordering kinetics for the growth of the ordered cholesteric liquid crystalline phase from the disordered isotropic melt is investigated at isothermal conditions after a temperature quench. The growth of a characteristic length, here the nucleus diameter, follows a universal growth law L ( t ) ≈ t n with the…
The transfer of CdS nanoparticles of dimensions 60 Å synthesized in an aqueous environment into petroleum ether (pet ether) by coordination of the nanoparticles with octadecanethiol (ODT) molecules present in the organic phase is described. The phase transfer of the CdS nanoparticles into pet ether occurs extremely ra…
Exploratory hydrothermal synthesis in the system Cs 2 O−SiO 2 −TiO 2 has produced a new polymorph of Cs 2 TiSi 6 O 15 (SNL-A), whose structure was determined using a combination of experimental and theoretical techniques ( 29 Si and 133 Cs NMR, X-ray powder diffraction, and density functional theory). SNL-A crystalliz…
The synthesis of the phenyl anchored podand H 4 L 1 fitted with four 3-carboxylate pyrazole arms and programmed for intermolecular interactions is reported, and its protonation constants are determined. Interaction with Ln 3+ ions (Ln = La, Eu, Lu) in dilute aqueous solutions leads to complexes with 1:1 and 1:2 metal−…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTInterpolymer Complexes through Hydrophobic Interactions: C60-End-Capped Poly(ethylene oxide)/Poly(methacrylic acid) ComplexesX. D. Huang and S. H. GohView Author Information Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543 Cite this…
Comb-shaped or hairy rodlike supramolecules can be obtained by hydrogen bonding rigid rod polymers and amphiphilic oligomers. Here we introduce a concept to achieve electrically conducting acid doped PANI to allow cylindrical self-organization. PANI is doped with camphorsulfonic acid (CSA) where 4-hexylresorcinol (Hre…
PVT properties were measured for mixtures of poly(ethylene glycol methyl ether)-350 + anisole and poly(ethylene glycol)-200 + anisole at temperatures from 298 K to 338 K and pressures up to 50 MPa. Excess volumes are positive for these two polymer solution systems. The isothermal compressibilities were calculated with…
The vapor pressures for praseodymium trihalides, PrCl 3, PrBr 3, and PrI 3, were measured above solid and liquid phases by the torsion method. In the covered temperature ranges, their values can be expressed by the following equations: PrCl 3 (s), lg( p /kPa) = 12.45 ± 0.20 − (16540 ± 200) K/ T (from 963 to 1045 K); P…
Amorphous ethylene−styrene interpolymers (ESIs) provide an excellent model system for testing contemporary concepts of molecular dynamics. Moreover, the results can be extrapolated to the chain reptation dynamics of amorphous polyethylene at ambient temperature which cannot be assessed by direct experimental technique…