Materials Literature
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We report the synthesis of porphyrazines (pzs), or tetraazaporphyrins, of the form H2[pz(An;B4-n)], where A is [S(CH2)3COOR]2 (R = n-Pr,H) and B is a fused beta,beta'-diisopropyloxybenzo group, including the compounds with n = 4 (6), n = 3 (7) and the trans compound with n = 2 (8) (Scheme 1). The synthesis employs Lin…
Highly conductive new aniline copolymers containing butylthio substituent have been first prepared from unsubstituted polyaniline, utilizing a concurrent reduction and substitution reaction performed in the solid-state matrix of polyaniline. The resultant copolymer film after one reaction treatment cycle was found to…
Here we describe the detection of live Pseudomonas aeruginosa using a sensing film containing a fourth-generation hydroxy-terminated polyamidoamine (PAMAM) dendrimer (i.e., G4-OH) and SYTOX Green fluorescent nucleic acid stain. The films are configured on simple, disposable plastic coupons or optical fibers and are in…
A hybrid density functional theory method previously developed for heterogeneous silica surfaces has been used to calculate model isotherms over a wide range of pore widths for the adsorption of nitrogen at 77 K within cylindrical pores having a clay-like surface. Using these models and the experimental isotherm data,…
Carbon black (CB) filled polymers display mechanical and electrical properties that depend not only on the volume fraction φ of the filler particles but also on their structure and on their distribution. Recently it has been shown that ultra-small-angle X-ray scattering measurements (USAXS) yield information on the ar…
Reaction of the metal acetates M(OAc)2xH2O with di-tert-butyl phosphate (dtbp-H) (3) in a 4:6 molar ratio in methanol or tetrahydrofuran followed by slow evaporation of the solvent results in the formation of metal phosphate clusters [M4(mu 4-O)(dtbp)6] (M = Co (4, blue); Zn (5, colorless)) in nearly quantitative yiel…
A novel approach for chemical modification of carbon nanotubes was developed, which involved radio frequency glow-discharge plasma activation, followed by chemical reactions characteristic of the plasma-generated functional groups. For instance, amino-dextran chains have been immobilized onto acetaldehyde-plasma-treat…
Inverse metal-stripe polarizers are optical elements that have a higher transmission efficiency in TE polarization than in TM polarization. This phenomenon is explained by the wave-guiding effect of the TM-mode in the grating and by surface plasmons on the metal stripes. The rigorous coupled-wave method is used for ca…
NASICON (Na 3 Zr 2 Si 2 PO 12 ) has been prepared by a nonhydrolytic route reacting OP(OBu) 3, SiCl 4, Zr(O t -Bu) 4, and NaO t -Bu in acetonitrile. The progress of the reaction was monitored by measuring 31 P and 13 C NMR spectra in the liquid phase and mass spectra of the reaction mixture. The spectroscopic analysis…
We present large scale Monte Carlo simulations of polymer blends, cross-linked in the absence of interactions and quenched into the two-phase region. Our results show, in agreement with the experiments, that the characteristic length of the microphases is much larger than the mean radius of gyration of the network str…
The relationship between the self-affine structure of cold-deposited films and the surface-enhanced Raman (SERS) intensity of benzene adsorbed on the films is examined. Based on variable temperature STM studies the structure of cold-deposited silver films is shown to be self-affine with a fractal dimension ∼2.6, more…
General and exact relationships within the nonlocal (pair–site) reactivity context are explicitly derived in the framework of density functional theory. The equations are expressed in terms of linear response functions and associated kernels of the Fukui function and its derivatives with respect to the electron number…
In this paper, the heteroaggregation of opposite sign hard and soft colloidal particles has been studied by static and dynamic light scattering. The structure of the aggregates, as well as the aggregation kinetics, have been investigated. At low electrolyte concentration, where both long-range electrostatic repulsive…
We studied the atomic structure of a multiple-twin triple junction in silicon, formed by the convergence of two ${111}$ and one ${221}$ symmetric-tilt grain boundaries. Molecular-dynamics simulations with the Stillinger-Weber potential and constant-traction border conditions were performed on several triple junction c…
Tunneling spectra are measured on the charge-density wave (CDW) compound ${\mathrm{LaTe}}_{2}$ and the isostructural antiferromagnet ${\mathrm{CeTe}}_{2}$ with ${T}_{N}=4.3\mathrm{K}$ by a break-junction method. In contrast to the well-developed CDW gap $2\ensuremath{\Delta}=0.9\mathrm{eV}$ wide for ${\mathrm{LaTe}}_{…
Molecular clips possessing U-shaped cavities have been functionalized on their convex side with long aliphatic tails. These molecules form dimers which self-assemble into malleable lamellar thin films. Upon addition of a guest (methyl 3,5-dihydroxybenzoate), a 1:1 host-guest complex is formed, which prohibits clip dim…
We present a novel methodology for the conjugation of Pluronic poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) block copolymers with a fluorescein derivative, 5-(4,6-dichlorotriazinyl) aminofluorescein (5-DTAF), at room temperature under aqueous conditions. Two Pluronic block copolymers, F68 with molec…
Essentially high-spin [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) were isolated from an aqueous reaction mixture. Both salts undergo an abrupt transition to low spin below room temperature, that for the thiocyanate occurring in two steps and the high-spin Æ low-spin Æ high-spin cy…
Single particle dynamics of water confined in a nanopore is studied through computer molecular dynamics. The pore is modeled to represent the average properties of a pore of Vycor glass. Dynamics is analyzed at different hydration levels and upon supercooling. At all hydration levels and all temperatures investigated…
We have developed a technique to accelerate the acquisition of effectively uncorrelated configurations for off-lattice models of dense polymer melts that makes use of both parallel tempering and large-scale Monte Carlo moves. The method is based upon simulating a set of systems in parallel, each of which has a slightl…