Materials Literature
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An adjacent dibenzotetraazaporphyrin, in which two benzene units are fused to the adjacent pyrrole rings of tetraazaporphyrin skeleton, has been synthesized as a copper complex for the first time and characterized by electronic absorption and magnetic circular dichroism spectroscopy, by cyclic voltammetry and spectroe…
Crystallization kinetics in a homogeneous copolymer of ethene and 1-octene with appended long chain branches has been investigated in real time by means of time-resolved light scattering under H V (cross-polarized) and V V (parallel-polarized) optical alignments using a CCD camera system, simultaneous small angle-X-ra…
The dynamic mean-field density functional method is adapted to describe phase separation in the presence of geometrical constraints. We observe that inclusion of small filler particles (such as rods) already has a dramatic effect on the morphology of polymer melts. The effect is comparable to the effect of applied sim…
In a reaction proceeding within a nanoscopic volume, supramolecular clusters were transformed to polymer objects while retaining their shape and size. Spatial isolation of the cross-linkable blocks of oligobutadiene that were involved in this stitching reaction was achieved by self-assembly of the molecules that made…
Large and reverse hypsochromic and bathochromic shifts on either polaronic (1.29 eV) or bipolaronic (0.68 eV) bands have been determinated from electrochromic polypyrrole films by “in-situ” spectroelectrochemical measurements in the visible region during oxidation/reduction switching. Whatever the rate of the electroc…
We report on the results of extensive Brownian dynamics simulations of colloid phase separation due to depletion flocculation. We study in detail the effect of potential variation at fixed volume fraction of colloid and fixed range of interaction. We find a variety of nonequilibrium behaviors for quenches into the col…
Stickel, Fischer, and Richert [ J. Chem. Phys. 1996, 104, 2043] found the temperature dependence of the α - relaxation time, τ α ( T ), of many small-molecule glass-forming liquids undergoes a change at a characteristic temperature, T B . On the lowering of temperature, τ α ( T ) changes from one Vogel−Fulcher−Tammann…
The adsorption of lysozyme and bovine serum albumin (BSA) onto the surface of a hydrogel polymer has been characterized by neutron reflection and spectroscopic ellipsometry. The polymeric hydrogel was synthesized by copolymerizing methacrylate monomers bearing dodecyl chains and phosphorylcholine (PC) groups. The poly…
A transient metastable rotator phase occurring on crystallization of hexadecane into its triclinic phase from the supercooled melt was directly observed with time-resolved synchrotron x-ray scattering. In this system, the limit of supercooling (the crystallization temperature) is determined by the thermodynamic stabil…
Mesoporous aluminosilicate in the hexagonal phase (MCM-41) has been synthesized from fused fly ash solutions and cationic cetyltrimethylammonium bromide (CTAB) surfactants. We provide direct evidence that an MCM-41 aluminosilicate with a homogeneous chemical composition of Si/Al = 13.4 can be prepared with cationic su…
We examine the effective diffusion coefficient of composites containing randomly placed, impermeable, oriented disks of high aspect ratio. We extend previous work by providing a quantitative framework in which to examine disorder and polydispersity effects, as well as treating explicitly the crossover from the dilute…
A synthetic concept of preparing dense polymer brushes on planar surfaces is described, in which a self-assembled monolayer (SAM) of biphenyllithium moieties on gold substrates is used to initiate anionic polymerization of styrene. The thickness of the resulting dry polystyrene brush, as estimated by ellipsometry and…
Optical surfaces coated with a thin layer to improve light transmission are ubiquitous in everyday optical applications as well as in industrial and scientific instruments. Discovered first in 1817 by Fraunhofer, the coating of lenses became standard practice in the 1930s. In spite of intensive research, broad-band an…
The synthesis of massive arrays of monodispersed carbon nanotubes that are self-oriented on patterned porous silicon and plain silicon substrates is reported. The approach involves chemical vapor deposition, catalytic particle size control by substrate design, nanotube positioning by patterning, and nanotube self-asse…
CVD SiC and sintered alpha-SiC samples were exposed at 1316 C in a high pressure burner rig at total pressures of 5.7, 15, and 25 atm for times up to 100h. Variations in sample emittance for the first nine hours of exposure were used to determine the thickness of the silica scale as a function of time. After accountin…
The morphology of chiral ( R )- and ( S )-poly(epichlorohydrin) (PECH) single crystals grown from solution was studied to obtain insight into the mechanism by which the chiral character of the main chain can be transmitted to higher organizational levels, such as the lamellar twisting orientation in banded spherulites…
By employing the ethylenediamine extraction reaction of a pentanary alloy with the nominal composition of K4AuSn2Sb2Te11, the discrete ternary Zintl anion [AuSn2Te6]3- was isolated. The structure of the [AuSn2Te6]3- anion is composed of a dimeric [Sn2Te6]4- anion and a [AuTe2] unit. A highly strained [AuSn2Te6]3- anio…
Defluorination of a film of highly oriented poly(tetrafluoroethylene) (PTFE) was carried out by the action of lithium and sodium amalgams. The reaction yields a composite product containing carbon with the equivalent amount of alkali metal fluoride. This material was studied by X-ray photoelectron spectroscopy, Raman…
A new dendrimer ( 1 ), which contains phenol groups in the exterior for solubilization in aqueous alkaline solution and calix[4]resorcinarene in the interior to increase the molecular weight and number of the phenol group even in the lower generation, was designed as new negative-working, alkaline-developable photores…
The spontaneous precipitation of calcium sulfate in supersaturated solutions over the temperature range between 25.0 and 80.0 °C was investigated by monitoring the solution specific conductivity during desupersaturation. From measurements of the induction times preceding the onset of precipitation the surface energy o…