Materials Literature
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An exploratory thermal interface structure, made of vertically oriented carbon nanotubes directly grown on a silicon substrate, has been thermally characterized using a 3-omega method. The effective thermal conductivities of the carbon nanotubes (CNT) sample, including the effects of voids, are found to be 74W∕mK to 8…
Magnesium hydride is cheap and contains 7.7 wt % hydrogen, making it one of the most attractive hydrogen storage materials. However, thermodynamics dictate that hydrogen desorption from bulk magnesium hydride only takes place at or above 300 degrees C, which is a major impediment for practical application. A few resul…
We have investigated the structure of films thermally evaporated onto anodic aluminum oxide substrates that are patterned with a hexagonal array of 34 and 80 nm diameter holes spaced by 100 nm. Over a range of film thicknesses, Pb and Sn films spontaneously self-assemble into an array of nanocrystals in registry with…
Abstract Electrical conductivity in a novel nonconjugated conductive polymer, poly(β‐pinene), has been measured as a function of molar concentration of iodine. The conductivity increases about 10 orders of magnitude to a maximum value ˜8 × 10 −3 S/cm. The molar concentration of iodine, corresponding to saturation, is…
We report a series of silica, titania, and zirconia microstructures synthesized within swollen poly(dimethylsiloxane) (PDMS). Voids created by solvent-swelling the polymer are used to template the product. The inorganic morphologies range from spheres to networks, depending upon the nature of the polymer, its degree o…
The reactions between Ti(O(i)Pr)(4) and Zr(2)(O(i)Pr)(8)(HO(i)Pr)(2), respectively, and lead 2-ethylhexanoate Pb(O(2)CC(7)H(15))(2) have been investigated at rt and by heating. The initial mixed-metal species, characterized by single-crystal X-Ray diffraction, were adducts namely Pb(4)Zr(4)(mu-O(2)CR')(8)(mu-OR)(6)(mu…
(3S,6S)-3-Isopropyl-6-methyl-morpholine-2,5-dione (1), and (3S,6S)-3,6-dimethyl-morpholine-2,5-dione (2), do not enter into ring-opening polymerization reactions with metal catalyst precursors commonly employed for lactides, and with Sn(II) octanoate, only low molecular weight oligomers are obtained. Reactions with R2…
Abstract Summary: 5,5′,6,6′‐Tetra(trimethylsiloxy)‐4,4,4,4′‐tetramethyl‐1,1‐spirobisindane was polycondensed with 1,4‐dicyanotetrafluorobenzene under variation of solvent temperature, time, and feed ratio. Under optimized reaction conditions, all products detectable by MALDI‐TOF mass spectrometry (up to masses around…
We found that tri-9-anthrylborane (TAB) recrystallized from benzene produced both red cubic-like (R-form) and orange hexagon-like crystals (O-form). In both crystal forms, six TAB molecules are arranged in a honeycomb structure in the ab plane and benzene molecules are incorporated in the honeycomb structure, whose sp…
We demonstrate that large and simultaneous improvements in permittivity, tunability, and leakage current density of (Ba,Sr)TiO3 (BST)-based thin-film capacitors can be achieved by yttrium doping. We have found that, for a low deposition temperature (520 °C) sputtering process, Y-doped BST capacitors exhibit tenfold lo…
PEGylated polyamidoamine (PAMAM) dendrimers as drug carriers have been a topic of interest because of their biomedically favorable features, including minimal toxicity, reduced immunogenicity, and excellent solubility in aqueous and most organic solutions. A PEG shell on dendrimer surface may provide steric hindrance,…
Abstract The thermal degradation kinetics of polypropylene/clay microcomposites and nanocomposites were studied by thermogravimetric analysis. In comparison with pure polypropylene, the reaction order of the degradation of the composites became zero‐order, and the activation energy increased dramatically. The zero‐ord…
We have engineered a new class of pH-responsive polymer films on gold surfaces by first developing a controlled, surface-catalyzed polymerization to prepare a copolymer film consistent with poly(methylene-co-ethyl acetate) and subsequently hydrolyzing the ester side chains to varying extents to yield carboxylic acids…
A simple, novel method to produce porous 2,3-dialdehydecellulose (DAC) membranes as a potential tissue-engineering scaffold has been developed from methylolcellulose by the simultaneous water-induced phase separation and sodium chloride salt leaching techniques, followed by oxidation with sodium periodate in water. Me…
Electric and magnetic properties were investigated on p-type Zn1−xCrxTe doped with nitrogen (N) as an acceptor. Thin films of p-Zn1−xCrxTe(x≦0.09) were grown by molecular-beam epitaxy with the supply of N2 gas excited by rf plasma. With the increase of Cr composition x at an almost fixed N concentration of the order o…
A strong generic coupling between self-localized solitons and conformations of a pi-conjugated polymer chain is demonstrated through ab initio calculations and the underlying mechanisms revealed by using an extended Hubbard model. We show that significant chain bending and twisting of trans- and cis-polyacetylene resu…
Variable temperature transport between 1.4 and 300 K, structural imaging, and theoretical calculations were used to characterize the properties of electrically active 24 degrees and 36.8 degrees [001] tilt SrTiO3 grain boundaries with 0.1 at. % niobium doping. An anomaly in boundary resistance and capacitance characte…
Abstract A versatile coupling reaction for the preparation of polybutadiene–poly‐(hexafluoropropylene oxide) (BF) diblock copolymers is described. Six diblock copolymers with different block lengths were characterized by nuclear magnetic resonance spectroscopy and size exclusion chromatography; all six had total molec…
Abstract Summary: The synthesis of new N ‐cyclopentyl‐ exo , endo ‐norbornene‐5,6‐dicarboximide (CpNDI) ( 3a ) and N ‐cyclohexyl‐ exo , endo ‐norbornene‐5,6‐dicarboximide (ChNDI) ( 3b ) monomers was carried out. From these monomers, two polynorbornene dicarboximides with cyclopentyl and cyclohexyl pendant groups, poly…
The biological safety of degradation products from degradable biomaterials is very important. In this study a new method is proposed to test the cytotoxicity of these degradation products with the aim to save time, laboratory animals, and research funds. A biodegradable polyurethane (PU) foam was subjected to this tes…