Materials Literature
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A new method is described for the synthesis of high-quality CdSe nanocrystals (NCs) that eliminates the need for tri-octylphosphine oxide (TOPO). This new method is an adaptation of previously reported methods that use Cd salts as precursors for the CdSe NCs. High-boiling esters and ketones such as hexadecyl hexadecan…
A completely soluble optically active polyaniline-multiwalled carbon nanotube composite was investigated by spectroscopic and microscopic techniques. It was found that the polymer's optical activity was retained in the presence of carbon nanotubes. Solutions were found to be easily processable into thin films, which e…
X-ray analysis has been carried out on a crystal of the collagen model peptide (Hyp(R)-Hyp(R)-Gly)10 [where Hyp(R) is 4(R)-hydroxyproline] with 1.5 A resolution. The triple-helical structure of (Hyp(R)-Hyp(R)-Gly)10 has the same helical parameters and Rich and Crick II hydrogen bond patterns as those of other collagen…
Interfacial segregation of diblock, gradient, and random copolymers was measured using forward recoil spectrometry. The polymers were synthesized by a ring-opening metathesis polymerization, allowing a high degree of control over the sequence distribution. The norbornene-based monomers have reactivity ratios close to…
High concentration (5at.%) Ni was incorporated into a chemical vapor deposition-grown GaN film by using a thin protecting Ni layer on top of the GaN film during ion implantation. After etching off the protecting layer, subsequent annealing up to 800°C under flowing N2 resulted in a p-type GaN with apparent ferromagnet…
Abstract Complexes [Au 2 Ag 2 (C 6 F 5 ) 4 L 2 ] n , where L = 1,10‐phenanthroline (phen), 2,2′‐bipyridine (bipy) or tetrahydrothiophene (tht), have been synthesized by reaction of NBu 4 [Au(C 6 F 5 ) 2 ] with Ag(SO 3 CF 3 ), and the addition of phen or bipy thereafter, or with [Ag(SO 3 CF 3 )(tht)]. The organometalli…
Abstract Poly(acrylic acid) (PAA) was derivatized through the reaction of its pendant carboxylic acid (CO 2 H) groups with a wide range of amine‐terminated molecules. These molecules contained alkyl, hydroxyl, sulfonic acid, or perfluoroalkyl groups. N‐substitution of PAA was carried out by the simple addition of 4‐(4…
Intrinsic fluorescence quenching of humic substances (HS) and the sensitization of Ln3+ luminescence (Ln3+ = Tb3+, Eu3+) in HS complexes were investigated. Both measurements yielded complementary information on the complexation of metals by HS. Large differences between fulvic acids (FA) and humic acids (HA) were foun…
Abstract Summary: This contribution describes the graft polymerization of polystyrene (PS) by atom transfer radical polymerization at 50, 60, and 75 °C. Thick PS brushes were grown from initiator‐functionalized PGMA layers on silicon, and constant growth rates provide indirect evidence that the polymerizations were co…
We derive explicit expressions in the frame of the optical indicatrix for the second-order effective nonlinearity in biaxial crystals with point groups 2, m, and 1, governing the conversion efficiency in three-wave nonlinear optical interactions. The tabulated expressions for the monoclinic symmetry classes 2 and m ar…
The potential applications as nanostrain sensors and tunable frequency oscillators make it important to analyze the natural vibrational frequency of deformed carbon nanotubes. We perform extensive molecular-dynamics and continuum analyses to explore the effects of several basic deformation modes (axial tension and com…
Hyperfine interactions (HFI) on the nuclei of the first coordination sphere water molecules in a model [Gd(H(2)O)(8)](3+) aqua complex and in the magnetic resonance imaging contrast agent [Gd(DOTA)(H(2)O)](-) were studied theoretically. Density functional theory (DFT) calculations combined with classical molecular dyn…
Silvered polyimide films have been prepared by potassium hydroxide hydroxylation of polyimide film surfaces and incorporation of silver ions through subsequent ion exchange. Thermal curing not only recycloimidized the poly(amic acid) into polyimide, but also reduced silver ions into silver atoms and near-atomic silver…
We present complete experimental determinations of the tunnel barrier parameters (two barrier heights, junction area, dielectric constant, and extrinsic series resistance) as a function of temperature for submicrometer Ni-NiO-Ni thin-film tunnel junctions, showing that when the temperature-invariant parameters are for…
The manganese-oxo "cubane" core complex Mn(4)O(4)L(1)(6) (1, L(1) = Ph(2)PO(2-)), a partial model of the photosynthetic water oxidation site, was shown previously to undergo photodissociation in the gas phase by releasing one phosphinate anion, an O(2) molecule, and the intact butterfly core cation (Mn(4)O(2)L(1)(5+))…
We present results for high-resolution small-angle single-crystal X-ray diffraction of hard-sphere silica colloidal crystals. Our results indicate that the stacking probability α of finding an fcc stacking sequence in a strongly compressed sample can only have two discrete values of either 0.5 (for rhcp) or 1 (for fcc…
The shear-rate dependence of viscosity is studied for model polymer melts containing various concentrations of spherical filler particles by molecular-dynamics simulations, and the results are compared with the experimental results for calcium-carbonate-filled polypropylene. Although there are some significant differe…
Abstract A novel route to prepare polyaniline (PANI)‐supported Pd(0) nanoparticles by a one‐pot chemical route is presented. Nanosized Pd(0) particles were first prepared by reduction of Pd(OAc) 2 using t ‐BuONa activated sodium hydride in refluxing THF. A ligand exchange with aniline on t ‐BuONa‐stabilized Pd(0) part…
The demonstration that quantitative and sensitive analysis can be carried out using surface enhanced resonance Raman scattering (SERRS) prompted a discussion and investigation of the main variables which are within the control of the analyst using colloidal silver as the substrate. Previous papers have dealt with the…
Control of nonspecific interactions between bioanalytical surfaces and proteins in the analyte is critical in the design of biosensor systems. Here we explore poly(propylene sulfide- block -ethylene glycol) (PPS−PEG) di- and triblock copolymer adlayers on gold to gain such control. Chemisorption of the PPS block permi…