Materials Literature
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The chromicity of poly(aryleneethynylene)s (PAE) is discussed and described in this contribution. Four different types of PAEs will be scrutinized a) dialkyl-poly( para -phenyleneethynylene)s (dialkyl-PPEs), b) dialkoxy-PPEs, c) acceptor substituted PPEs, and d) heteroaryleneethynylenes that contain benzothiadiazole u…
Abstract The ultrasonic degradation of poly(bisphenol A carbonate), poly(ε‐caprolactone), and poly(vinyl acetate) was investigated with various solvents such as benzene, monochlorobenzene, and dichlorobenzene. The time evolution of molecular weight was determined using gel permeation chromatography. A limiting molecul…
Chaotic orientational dynamics of sheared nematic polymers is documented in laboratory experiments and predicted by Doi-Hess kinetic theory for infinitely thin rods. We address robustness of rheochaos when simple shear is modified by a planar straining flow, and the macromolecules have finite aspect ratio. We predict…
Molecular dynamics simulations of three kinds of linear low-density polyethylene (LLDPE) single-chain models with precisely controlled branching are performed. It is shown that the crystallinity of copolymers with branches shorter than C 10 H 21 decreases with increasing branch length, whereas for copolymers having br…
The Cu2GeTe3 compound crystallizes in the Imm2 (N° 44) space group, Z = 2, with a = 12.641(1) Å, b = 4.2115(2) Å, c = 5.9261(2) Å, V = 315.49(3) Å3. Its structure was refined from X-ray powder diffraction data using the Rietveld method. The refinement of 23 instrumental and structural variables led to Rp = 8.2%, Rwp =…
The reaction of a dipyrromethanedicarbinol with 2,2'-bipyrrole leading to meso-substituted [34]octaphyrin(1.1.1.0.1.1.1.0) and/or corrole was investigated to determine the effect of key reaction parameters on the distribution of the two macrocycles. Solvent, acid catalyst, acid quantity, oxidant, oxidant quantity, and…
Abstract In this article we review the complexation behavior of charged polymers adsorbed onto charged substrates. In the first part we summarize the results obtained on the adsorption properties of a single polyelectrolyte chain with one or several oppositely charged spherical colloids. The results of various simulat…
Surfaces whose reflectivity can be thermally controlled were formed on single crystals of silicon by using ion beams to create a nanocomposite layer consisting of VO2 precipitates embedded in a thin-film matrix of amorphous SiO2. The surface nanocomposite layer was produced by first thermally oxidizing a Si crystal to…
The reaction of elemental gold and selenic acid in Teflon-lined steel autoclaves leads to orange-yellow single crystals of Au2(SeO3)2(SeO4) (orthorhombic, Z = 4, Cmc2(1) (No. 36), a = 1689.1(3) pm, b = 630.13(8) pm, c = 832.7(1) pm, V = 886.2(2) angstroms3, Rall = 0.0452). In the crystal structure, Au3+ is surrounded…
Abstract Three new copper( II ) complexes of formula [Cu(2,2′‐bpy)(Phmal)(H 2 O)]·2H 2 O ( 1 ), [{Cu(2,2′‐bpym)(Phmal)}] n ( 2 ) and [{Cu(phen)(Phmal)}] n ·3 n H 2 O ( 3 ) (Phmal = phenylmalonate; 2,2′‐bpy = 2,2′‐bipyridine; 2,2′‐bpym = 2,2′‐bipyrimidine; phen = 1,10‐phenanthroline) have been prepared and their struct…
A novel graft copolymer was synthesized via graft copolymerization of an inimer, 2-(2-bromoisobutyryloxy)ethyl acrylate (BIEA), with ozone-pretreated poly(vinylidene fluoride) (PVDF) (the PVDF- g -PBIEA copolymer). Porous membranes could be fabricated from the copolymer solution by phase inversion. The BIEA polymer (P…
Effects of the chemical environment on devices utilizing organic semiconductors are discussed. It is convenient and justified to use silicon-based insulated gate field-effect transistors (IGFET) as the yardstick by which the performance of organic field-effect transistors (OFET) are measured. However, the same issues…
Nucleation of vanillin (VAN) in 2-propanol/water in the presence of additives, viz., acetovanillone (AVA), ethyl vanillin (EVA), guaiacol (GUA), guaethol (GUE), 4-hydroxyacetophenone (HAP), 4-hydroxybenzaldehyde (HBA), and vanillic acid (VAC) is investigated experimentally and by molecular simulations. In the experime…
Second- and third-harmonic generation in single-walled carbon nanotube films is experimentally investigated with the fundamental 1064nm radiation from a Q-switched Nd:YAG laser. Measurements were performed both on commercially available carbon nanotubes and on samples of carbon nanotubes grown with a catalyst-free met…
We report here a direct generation of measurable voltages and currents when a gas flows over a variety of solids even at the modest speed of a few meters per second. The underlying mechanism is an interesting interplay of Bernoulli's principle and the Seebeck effect: Pressure differences along streamlines give rise to…
Using plasma-enhanced chemical vapor deposition (PECVD) based on fluorine chemistry, the limitations hindering the practical use of cubic boron nitride (cBN) films in mechanical applications have been overcome. The CVD method presented is characteristic with (a) the direct cBN growth on diamond without soft, noncubic…
Sodium naproxen is an antiinflammatory nonsteroidal drug used in the treatment of rheumatoid and arthritic diseases. Three pseudopolymorphic forms have been reported in the literature, along with characterizations of anhydrous and dihydrated forms. In the present work, the monohydrated form of sodium naproxen was prep…
Abstract Samples of oxidized cellulose (OC) with various carboxyl contents and degrees of crystallinity were obtained by the oxidation of native and mercerized cellulose with a solution of nitrogen(IV) oxide in CCl 4 . A detailed characterization of these OC samples was performed. The effect of oxidation conditions (c…
Cobalt(II) meso-tetrakis(4-hexadecylamidophenyl)porphyrin self-assembles in ethanol/1-propanol 2/1 (v/v) to form a rodlike micelle with nanoscale dimensions; the nanorod is a face-to-face aggregate having a hydrophobic corona around a polar core and is thus characterized as a reverse micelle.
A new type of protective microcontainer, capable of preventing oxidation of encapsulated compounds by low molecular weight oxidizing agents, was demonstrated. These microcontainers (microcapsules) are hollow spheres with the shell made of layer-by-layer assembled polyelectrolytes with an engineered outermost layer. Th…