Materials Literature
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Using the Langmuir Blodgett (LB) technique, monolayers of spherical polymer particles were investigated at the air−water interface. In this study, LB methods were used to examine particle interactions, packing, morphology, and viscosity of polymer films. Films composed of polymer microgels (diameters of 113−427 nm) ha…
The CO interaction with Au + /dealuminated H-mordenite as well as with the nondealuminated samples, at room temperature, after evacuation at different temperatures (343, 393, 453, and 573 K) has been studied by in situ Fourier transform infrared spectroscopy. The Au + −CO band at 2192 cm -1 of the dealuminated sample…
Isotactic (it-) poly(methyl methacrylate) (PMMA) and syndiotactic (st-) poly(ethyl methacrylate) (PEMA) and poly(propyl methacrylate) (PPMA) were synthesized by anionic polymerization in toluene at −78 °C with t- C 4 H 9 MgBr and t- C 4 H 9 Li/(C 2 H 5 ) 3 Al, respectively, as initiators/coordinators. Combined it- and…
The adsorption of CO (1% CO/He mixture, 1 atm total pressure) in the presence of several gases is studied on a reduced 2.9% Pt/Al 2 O 3 catalyst in the 300−740 K temperature range by using Fourier transform infrared spectroscopy. A strong IR band is observed at 2075 cm - 1 in the absence of a second gas associated to…
The aim of this paper is to dissect the hierarchical structures of BaTiO 3 particles into primary, secondary, tertiary, and quaternary structural levels and to thoroughly review the corresponding structure−ferroelectricity relationships at all levels. This analytical framework is of growing importance for the fundamen…
The use of nanometer-sized gold particles as templates for the synthesis of hollow poly(pyrrole), poly( N -methylpyrrole), and poly(3-methylthiophene) is described in this paper. Diffusion coefficients of small molecules through the capsule shell were found to vary by almost 3 orders of magnitude depending on the poly…
Zinc(II) and cadmium(II) coordination networks with m -pyridinecarboxylate bridging ligands, Zn(nicotinate) 2, 1, Cd(nicotinate) 2, 2, Cd{3-[2-(4-pyridyl)ethenyl]benzoate} 2, 3, Zn 4 {3-[2-(4-pyridyl)ethenyl]benzoate} 8 ·{3-[2-(4-pyridyl)ethenyl]benzoic acid}·(H 2 O), 4, Zn{4-[2-(3-pyridyl)ethenyl]benzoate} 2 ·H 2 O,…
We present a method for obtaining well-localized Wannier-like functions (WFs) for energy bands that are attached to or mixed with other bands. The present scheme removes the limitation of the usual maximally-localized WFs method (N. Marzari and D. Vanderbilt, Phys. Rev. B 56, 12847 (1997)) that the bands of interest s…
Rhodium auf einem Titanoxid/Siliciumoxid-Träger wird durch 1 modelliert, das aus [{Cp*TiMe(μ-O2SiPh2)}2] 2 und [{Rh(OH)(cod)}2] hergestellt werden konnte. 2 und sein dreifach verbrücktes Derivat [Cp*Ti(μ-O2SiPh2)3TiCp*] 3 können als molekulare Modelle des Titanoxid/Siliciumoxid-Systems angesehen werden. Die Verbindung…
1,2-Diaminoethane (en) and FeCl3 give (enH2) [FeCl5(H2O)] (1) in concentrated HCl, extending the aquapentachloroferrate(III) series. For 1: C2H12N2Cl5OFe, orthorhombic, P2(1)2(1)2(1), a = 14.531(6) A, b = 10.772(4) A, c = 6.888(2) A, Z = 4. Diazabicyclo[2.2.2]octane dihydrochloride (DABCO-2HCl) and FeCl3 in concentrat…
Growth rate and effects of doping sodium in potassium dihydrogen phosphate (KDP) solution have been studied in crystals grown by solution evaporation and slow cooling methods. The crystals were grown in a KDP solution doped with different concentrations of sodium ions. The rates of growth along the thickness and width…
1,3,5-tripyrrolidinobenzene is the first example of an aromatic amine that forms σ dimers during oxidation/reduction cycles [Eq. (1); X−=ClO4−], and thus turns out to be an efficient molecular switch. Surprisingly, such σ dimers are relatively stable intermediates during the formation of conjugated oligomers and polym…
Abstract The stability of poly(phenylacetylene)s in solution was systematically studied. Cis–transoidal poly(phenylacetylene) prepared with a Rh catalyst readily underwent autoxidative degradation into oligomers, whereas a W‐based polymer with a trans‐rich geometrical structure degraded slowly under similar conditions…
The excitonic luminescence of a highly ordered single conjugated polymer chain is studied by microphotoluminescence. At $T\ensuremath{\le}10\mathrm{K}$ it consists of a single Lorentzian line. The linewidth increases linearly with $T$ between 6 and 60 K, from $350\ensuremath{\mu}\mathrm{eV}$ at 6 K, indicating a pure…
Mindestens drei Phthalocyaninylreste können Phosphoniumionen enthalten, wie es z. B. im Salz 1 der Fall ist. Solche Phosphoniumionen sind durch eine Pd-katalysierte Reaktion zugänglich, bei der Phenyl- gegen Phthalocyaninylreste ausgetauscht werden. Erste Untersuchungen an 1 und verwandten Salzen bezüglich ihrer nicht…
„Unschuldiges“ Verhalten eines typischen „nichtunschuldigen“ Liganden wurde für den ersten strukturell charakterisierten diskreten Metallkomplex mit vierfach verbrückendem TCNQ festgestellt. Die Koordination von vier [Re(CO)3(bpy)]+-Einheiten (siehe Bild; C: schwarz, N: grün, O: blau, Re: rot) erleichtert die Reduktio…
Ab initio MO calculations at the CCSD(T)/6-311++G(2df,p)//MP2/6-311++G** level have been carried out to determine the reaction energies and Gibbs energies of the homolytic dissociation of the S-S bonds in the chainlike sulfanes H2Sn (n = 2-4). Good agreement with the experimental data is observed. At the same level of…
Magnetic colloidal particles were prepared by a coprecipitation method. The particles were composed of nanometer-sized superparamagnetic Fe(3)O(4) particles stabilized by lauric acid. Then, magnetic agar gel beads were produced by a water-in-oil emulsification method using a mixture of agar solution and the magnetic c…
We report the occurrence of a reentrant twist grain boundary phase, which we designate as Re- ${\mathrm{TGB}}_{A}$. Microscopic observations on a nonsymmetric dimer showed the phase sequence Iso-- ${N}^{*}$-- ${\mathrm{TGB}}_{A}$--Sm- $A$--Re-- ${\mathrm{TGB}}_{A}$-- ${\mathrm{TGB}}_{{C}^{*}}$. Here ${N}^{*}$ and Sm-…
Bacterial cellulose (BC) production was carried out in a batch cultivation of Acetobacter xylinum in a 50-L internal loop airlift reactor by addition of water-soluble polysaccharides into the medium. When 0.1% (w/w) agar was added, BC production reached 8.7 g/L compared with 6.3 g/L in the control, and duration of the…