Materials Literature
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A polymer, PMGI, serves as a template to generate uniformly distributed iron nanoparticles with controlled size. These nanoparticles have proven to be excellent catalysts for generating carbon nanotubes (CNTs). The catalyst locations can be defined by a single photolithography step for spatially selective growth of CN…
The synthesis and characterization of wedge−coil block molecules with a poly(ethylene oxide) coil of 77 ( 1a ), 91 ( 1b ), 114 ( 1c ), and 182 ( 1d ) ethylene oxide units are described. The self-assembling behavior of these block polymers in the melt state was investigated by optical polarized microscopy, differential…
Abstract Cu–Pd/β-zeolites (BEA) are excellent catalysts for the selective hydrogenation of NO3− with H2 to harmless products. 1.2 wt % Cu–1.0 wt % Pd/BEA shows a high selectivity for N2 + N2O (14 and 80% at 278 K, respectively), while suppressing NH3 production (6%, 3 ppm from 200 ppm of NO3−). By coupling the catalys…
Absorption, emission, and excitation spectra for solid-state and solution of Tb(III), Dy(III), and Gd(III) complexes with the polypyridine ligand 6,6'-bis[bis(2-pyridylmethyl)-aminomethyl]-2,2'-bipyridine (C36H34N8) are presented. Measurements of excited-state lifetimes and quantum yields in various solvents at room t…
A simple procedure is described that locks small quantities of SF6, CO2, and 13CO2 into opened single-walled carbon nanotube (SWNT) bundles and keeps the gas in the SWNTs above the desorption temperature of these molecules. The technique involves opening the SWNTs with ozonolysis at 300 K followed by vacuum-annealing…
Abstract By using n-hexylamine as a catalyst of sol–gel reaction of tetraethoxysilane in uncured natural rubber matrix, spherical silica particles of ca. 46 nm were homogeneously generated in situ at a high content, i.e., 71 parts per one hundred rubbers by weight. The mechanical properties of this soft nanocomposite…
Spectroscopic and kinetic properties of a new photochromic medium, consisting of nanocrystals of spyropyran molecules (1,3-dihydro-1,3,3,5',6',pentamethyl-spiro[2H-indole-2,2'-[2H]pyrano [3,2-b]pyridinium] iodide) embedded in an organo-silicate sol-gel film, are presented and compared to microcrystals obtained by slow…
The synthesis of new polymers, poly(biphenylmethylene)s, derived from bistriflates of bisphenol-type monomers, by Ni(0)-mediated polymerization has been presented. These polymers are interesting because of the nature of the polymer backbone that contains biphenyl units separated by substituted methylene units. The sol…
The properties of Mo ultrathin films deposited on a TiO2(110) surface were investigated by scanning tunneling microscopy (STM) and spectroscopy (STS), as well as by Auger electron spectroscopy (AES). The substrate exhibited mainly large (1 x 1) terraces decorated by additional [001] rows (missing or added 1D structure…
The adsorption of a polyacrylamide (MW 14600) and two polysaccharides (MW 9260 and 706 x 10(3)) onto model silica surfaces of different hydrophobicities was investigated. In all cases, adsorption adhered to the Freundlich isotherm, reflecting the heterogeneous character of the solid substrates. The latter strongly inf…
A hybrid approach incorporating a computational fluid dynamics (CFD) package and process simulation tool was employed to simulate the steady-state crystallization of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in a Y-mixer crystallizer. Mixing effect was intensively investigated through the three-dimensiona…
Abstract A new ion-pair complex, [VBzPy][Ni(mnt)2], where [VBzPy]+ = 1-(4′-vinylbenzyl)pyridinium and mnt2− = maleonitriledithiolate, has been synthesized. The cations and anions stack into completely separated columns and Ni(III) ions form a uniformly spaced one-dimensional (1-D) zigzag chain within a [Ni(mnt)2]− col…
Introduction of photoactive perylenediimides into the self-directed supramolecular silsesquioxane systems gives superlong tubular structure with length of several hundred micrometers and diameters ranging from 1 to 9 μm as determined by FE-SEM. XRD demonstrated that the wall of the tubes arranged in lamellar structure…
Starting from B, B ‘, B ‘ ‘-triethynylborazine ( 1 ), an easy construction kit for highly durable Si−B−C−N ceramic materials is presented. Hydrosilylation of 1 with HSiRCl 2 (R = Cl, Me, Ph) using Pt/C as catalyst results in the novel precursor molecules 2 and 3 . Subsequent linking reactions with MeNH 2 or hydrogenat…
The ring-opening multibranching polymerizations of 1,6-anhydro-β- d -glucopyranose ( 1 ) and 1,6-anhydro-β- d -galactopyranose ( 2 ) have been studied in order to synthesize hyperbranched polysaccharides. The solution polymerization in propylene carbonate and the bulk polymerization of 1 and 2 using a thermally induce…
High-temperature neutron diffraction (ND) experiments have been carried out in two representative members of the Li 3 x La 2/3 - x TiO 3 series ( x = 0.067 and 0.167), to analyze the influence of temperature on the perovskite structure. In the orthorhombic Li-poor ordered member Li 0.2 La 0.6 TiO 3 ( Cmmm space group)…
Steady-state and time-resolved photoluminescence spectroscopy are used to examine the photoluminescent properties of nanocrystal-polymer composites consisting of colloidal PbS nanocrystals blended with poly(2-methoxy-5(2-ethylhexyloxy)-p-phenylene vinylene). Quenching of the emission from the conjugated polymer due to…
Yttrium oxide (Y 2 O 3 ) microprisms with interesting trilobal cross section were synthesized through a large-scale and facile hydrothermal method followed by a subsequent heat treatment. The size of the Y 2 O 3 trilobal prisms could be modulated from micro- to submicroscale with the increase of pH value. The as-forme…
A series of poly( p -phenylene 3,6-bis(4-( n -alkyloxy)phenyloxy)pyromellitimide)s (C n -PMDA-PDA PIs) with various lengths of the n -alkyl bristle end group, which are well-defined polymer rods with two bristles per repeat unit of the polymer rod backbone, were studied as thin films using atomic force microscopy, opt…
The three main types of hydroxyl groups on a silica surface are classified as isolated, hydrogen bonded, and inaccessible. The isolated and hydrogen bonded groups are the most important as these readily exchange with D(2)O and thus are exposed to reactant molecules. However, it has generally been accepted that the ina…