Materials Literature
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Mesoscopically ordered silicate−surfactant composite materials of the M41S type synthesized in the presence of a swollen agent have been characterized by in situ and ex situ X-ray diffraction analysis. The key feature of the room-temperature synthesis is the use of a mixture of cationic and anionic surfactants as stru…
Ni nanowire arrays were produced by electrodeposition of Ni into self-assembled porous anodic alumina templates. With different anodization voltages, the wires show different surface morphologies. The temperature dependence of the coercivity and activation volume of wires with regular shape can be explained by thermal…
Reactions of [[MCl2(Cp*)]2] (1: M=Ir, 2: M=Rh) with bidentate ligands (L) such as 1,4-diisocyano-2,5-dimethylbenzene (a), 1,4-diisocyano-2,3,5,6-tetramethylbenzene (b), pyrazine (c) or 4,4'-dipyridyl (d) gave the corresponding dinuclear complexes [[MCl2(Cp*)]2(L)] (M=Ir: 3a, 3b, 5c, 5d; M=Rh: 4b, 6c, 6d), which were c…
A new class of malolactonate polymers and copolymers were synthesized, starting from the corresponding lactones, and then characterized. Different lateral groups were selected for these polyesters to achieve a wide range of materials characteristics and possible biological recognition. The monomers were prepared accor…
We present a review of recent progress in determining the surface structure of quasicrystals, with emphasis on their connections to mathematical tiling models. The review focusses in particular on the five-fold surface of icosahedral Al-Pd-Mn and the ten-fold surface of decagonal Al-Ni-Co. We also assess their potenti…
The glass transition in syndiotactic poly (methyl methacrylate) has been studied through atomistic molecular dynamics simulations performed at temperatures in the range from 297 K to 684 K. The mean squared deviations of atoms, monomers, and molecules from their initial positions were analyzed by means of a technique…
Laser irradiation of aqueous silver cations in the presence of a reducing agent induces growth of metallic silver particles. The picture shows a schematic illustration of a microscope setup that offers diffraction-limited spatial control of Ag deposition on a glass surface (RA=reducing agent, for example citrate).
High concentrations of reactive nanoparticulate materials in water is the answer for many applications, such as in biolabelling and coatings, as the established synthetic procedures used to obtain bulk quantities of nanoparticulate materials are limited to organic media. The procedure reported provides metallic nanopa…
Just four electrons in each case dominate delocalised ring currents (see schematic diagram) in free-base porphin, chlorin and magnesium porphin, as has been revealed by direct visualisation of the π current density. The remaining 22 π electrons (20 in chlorin) are magnetically inactive in the presence of a field perpe…
The influence of Li doping on the crystallization behavior, morphology, and enhancement in photoemission intensity of Gd 2 - x Y x O 3:Eu 3+ solid−solution was investigated. To maximize an effect of the Li component which is volatile at elevated temperature, the citrate route was adopted for the synthesis at low tempe…
Photoinduced magnetization in a magnet based on organic species is reported for the first time. Upon optical excitation in the blue region of spectrum, Mn(tetracyanoethylene)(x)*y(CH2Cl2) (x approximately 2, y is approximately 0.8) exhibits increased magnetic susceptibility at temperatures as high as 75 K, accompanied…
We report on the observation of electron-hole ( $e\ensuremath{-}h$) liquid (EHL) in diamond by time-resolved luminescence measurements under an intense femtosecond photoexcitation above the band gap. The EHL luminescence band is observed below the $e\ensuremath{-}h$ plasma band, showing a finite rise time of several t…
This work describes the static and the dynamic properties of fractionated microcrystal cellulose “whiskers” using elastic and quasi-elastic light scattering techniques. These colloidal particles have been obtained by acid hydrolysis from raw materials (tunicate, a marine animal) that lead to stable aqueous suspensions…
Makroskopische Mengen einheitlicher Wolfram-Nanodrähte 3 mit Durchmessern von 20 bis 80 nm und Längen zwischen 5 und 30 μm entstehen bei einer einfachen Vakuumpyrolyse lamellarer Komposite aus WO42−-Ionen und Cetyltrimethylammonium(CTA+)-Tensidionen. Die lamellaren Komposite bildeten sich aus Aggregaten von CTA-WO4-Io…
Bulk quantities of uniform tungsten nanowires 3 with diameters of 20–80 nm and lengths ranging from 5 to 30 μm were obtained by a simple vacuum-controlled pyrolysis process from lamellar composites of WO42− ions and cetyltrimethylammonium (CTA+) surfactant ions. The lamellar composites were obtained from aggregates of…
In a one-pot reaction, the tetranuclear iron chelate complex [Fe4(L4)4] 6 was generated from benzene-1,3,5-tricarboxylic acid trichloride (4), bis-tert-butyl malonate (5a), methyllithium, and iron(II) dichloride under aerobic conditions. Alternatively, hexanuclear iron chelate complex [Fe(L5)6] 7 was formed starting f…
We investigate local electrostatics within a polyelectrolyte multilayer formed from layer-by-layer self-assembly of QPVP/PSS (quaternized poly(vinylpyridine)/poly(styrenesulfonate)), through the strategy of embedding, within this multilayer, a weak polyacid, PMA (poly(methacrylic acid)). The methods mainly involved in…
We have aligned the microdomains of a polystyrene- b -poly(2-hydroxyethyl methacrylate)- b -poly(methyl methacrylate) (PS- b -PHEMA- b -PMMA) triblock copolymer during preparation from solution by virtue of an external electric dc field (1.8 kV/mm). Bulk samples cast in the presence of an electric field exhibit lamell…
Nanonetze: Aus einer Suspension von einwandigen Kohlenstoff-Nanoröhren (single-walled carbon nanotubes; SWNTs) wurden elektrisch leitende Gitter mit 8 bis 14 Knotenpunkten (siehe Bild) erhalten. Die entscheidenden Strukturparameter dieser „Miniaturschaltkreise“ wurden hauptsächlich durch chemisch gesteuerte Selbstorga…
Electron holography performed in situ inside a high resolution transmission electron microscope has been used to determine the magnitude and spatial distribution of the electric field surrounding individual field-emitting carbon nanotubes. The electric field (and hence the associated field emission current) is concent…