Materials Literature
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The unprecedented structural behavior of Co(3)(dipyridylamide)(4)Cl(2), characterized in two crystalline forms in which the tricobalt framework is either symmetric or highly nonsymmetric at room temperature is investigated by means of gradient-corrected DFT calculations. The isolated molecule is assigned a single ener…
A well-defined biodegradable block copolymer (PCL- b -PLLA, M n = 1.72 × 10 4, M w / M n = 1.37) of poly(ε-caprolactone) (PCL) and poly( l -lactide) (PLLA) was synthesized by a two-step ring-opening polymerization of ε-caprolactone and l -lactide. Furthermore, we found that α-cyclodextrin (α-CD) molecules may simultan…
An orthogonal, convergent route for the introduction of substoichiometric numbers of latent surface sites into dendrimers based on melamine is used to prepare targets that display one or two Boc-protected amines on the periphery. Asymmetry is the result of the stepwise incorporation of functionalized and unfunctionali…
The curvature effects in carbon nanotubes are studied analytically as a function of chirality. The $\ensuremath{\pi}$ orbitals are found to be significantly rehybridized in all tubes, so that they are never normal to the tubes' surface. This results in a curvature induced gap in the electronic band structure, which tu…
The effect of phonon scattering by surface roughness on the thermal conductance in mesoscopic systems at low temperatures is calculated using full elasticity theory. The low frequency behavior of the scattering shows novel power law dependences arising from the unusual properties of the elastic modes. This leads to ne…
Tensile drawing of poly(trimethylene terephthalate) (PTT) was studied at room temperature, 35, 50, and 75 °C. Instead of a typical increase in draw ratio with increasing temperature, the PTT draw ratio first increased, went through a maximum, and decreased; all occurred within a narrow range of temperature between T g…
Multiwalled BN nanotubes were synthesized via a chemical vapor deposition (CVD) route from a B 4 N 3 O 2 H precursor. Their morphological and structural features have been studied. It was suggested that the tips encapsulate boron oxynitride nanoclusters, which incorporate silicon, aluminum, and calcium and serve as th…
Anhydrous silylation of vinyltrimethoxysilane (VTMS) onto silica and zirconia substrates was investigated experimentally to demonstrate and quantify the effects of surface water on multilayer silylation. Silylation coverage was controlled by the availability of surface water, which is consumed in multilayer silylation…
Results are presented of a fully ab-initio calculation of impact ionization rates in GaAs within the density functional theory framework, using a screened-exchange formalism and the highly precise all-electron full-potential linearized augmented plane wave (FLAPW) method. The calculated impact ionization rates show a…
Nonequilibrium molecular dynamics simulations are used to study the shear thinning behavior of immiscible symmetric polymer blends. The phase separated polymers are subjected to a simple shear flow imposed by moving a wall parallel to the fluid-fluid interface. The viscosity begins to shear thin at much lower rates in…
High-resolution X-ray diffraction data show that the low-temperature superstructure of alpha-NaV2O5 has an F-centered orthorhombic 2a x 2b x 4c superlattice. A structure model is proposed, that is characterized by layers with zigzag charge order on all ladders and stacking disorder, such that the averaged structure ha…
We investigated the adsorption of a single atom, hydrogen and aluminum, on single-wall carbon nanotubes from first principles. The adsorption is exothermic, and the associated binding energy varies inversely as the radius of the zigzag tube. We found that the adsorption of a single atom and related properties can be m…
The effects of uniaxial strain on the structural, orbital, optical, and magnetic properties of ${\mathrm{LaMnO}}_{3}$ are calculated using realistic expressions for elastic energies, along with a tight-binding parametrization of the band theory and electron-phonon coupling. Tensile uniaxial strain of the order of 2% (…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTColloidal Imprinting: A Novel Approach to the Synthesis of Mesoporous CarbonsZuojiang Li and Mietek JaroniecView Author Information Department of Chemistry, Kent State University Kent, Ohio 44242 Cite this: J. Am. Chem. Soc. 2001, 123, 37, 9208–9209Publication Date (We…
A number of polyimides have gained considerable importance as high-performance polymers during the last 2 decades primarily because of their excellent thermal stability and toughness. Some applications, however, require property enhancements and the desired improvements can often be obtained through incorporation of c…
Lipophilic and hydrophilic dendra which are terminated with long alkyl chains and oligomeric poly(ethylene glycol) moieties, respectively, were synthesized, and these dendron species were used to functionalize single-wall (SWNT) and multiple-wall (MWNT) carbon nanotubes via amidation and esterification reactions. The…
Goniophotometry has enabled measurement of the angle that the surface of the cuticle (the scales) of a human hair fiber makes with the axis of the hair shaft. This measuring technique has been used to obtain the change of this scale angle with extension of a hair fiber under fixed conditions of temperature and relativ…
Abstract The effect of the solvent composition on the elasticity of strong and weak cation‐ and anion‐exchange resin beads was studied. Poly(styrene‐ co ‐divinylbenzene) resins containing sulfonic acid or quaternary ammonium groups and an acrylic acid resin crosslinked with divinylbenzene were immersed in water, NaCl…
We have conducted temperature and frequency dependent transport measurements in amorphous ${\mathrm{Nb}}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}$ samples in the insulating regime. We find a temperature dependent dc conductivity consistent with variable range hopping in a Coulomb glass. The frequency dependent response in…
A comprehensive photophysical study of protonated species of (tetra-tert-butylphthalocyaninato)zinc (tBu4ZnPcHnn+, n = 0–4) is reported. Singlet and triplet state properties have been measured and discussed with reference to the effects of protonation which occur at the azomethine bridging nitrogens of the phthalocyan…