Materials Literature
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This paper describes the use of patterned self-assembled monolayers (SAMs) in area-selective deposition of conducting polymers (polypyrrole and polyaniline) on insulating, hydroxyl-terminated surfaces such as Si/SiO 2 and glass. Patterned SAMs of octadecylsiloxane were generated on the hydroxyl-terminated surfaces usi…
Abstract Silicon‐based microfabrication of a novel chemical reactor (microreactor) having submillimeter flow channels with integrated heaters, and flow and temperature sensors is described. The potential application of this reactor to partial‐oxidation reactions is explored by using Pt‐catalyzed NH 3 oxidation as a mo…
A simple procedure has been developed to prepare thiol-derivatized nanoparticles of metals. The procedure involves the transfer of well-characterized metal hydrosols to a hydrocarbon medium containing the thiol. Thiol-derivatized nanoparticles Au, Ag, and Pt of near spherical shape forming nanocrystalline arrays have…
The stability of Si-MCM-48 to moisture and compression can be improved by trimethylsilylation, as a result of the increase in hydrophobicity. Moreover, the stability is retained after calcination, although the calcined material is no longer hydrophobic. This stabilizing effect was also observed for Si-MCM-41 and Ti-MC…
The dynamical theory of thermally activated resonant magnetization tunneling in uniaxially anisotropic magnetic molecules such as Mn${}_{12}\mathrm{Ac}$$(S=10)$ is developed. The observed slow dynamics of the system is described by master equations for the populations of spin levels. The latter are obtained by the adi…
Alternating copolymers, poly( p -phenylene[3-(alkylthio)-2,5-thienylene]- p -phenylene)s ( 4 ) were prepared by the nickel-catalyzed polymerization of 3-(alkylthio)-2,5-bis(4-chlorophenyl)thiophenes ( 3 ). Polymerizations were conducted in N -methyl-2-pyrrolidinone (NMP) in the presence of nickel chloride, zinc, triph…
Most physical models on quasicrystals, as well as the related experimental results, exhibit fractal energy spectra. In order to have a deep insight on relevant thermodynamic implications of this feature, we have performed analytical and high precision numerical calculations of the specific heats ${C}_{n}^{\mathrm{band…
The electrochemical activities of films prepared from chemically synthesized polypyrrole and a polypyrrole/ montmonrillonite nanocomposite are examined using cyclic voltammetry and chronopotentiometry. The nanocomposite exhibits redox chemistry at potentials ( V p , c = − 1500 , V p , a = − 1100 mV ) approximately 1 V…
We present a new approach for calculating generalized stacking-fault energies, which allows for in-plane relaxation of atoms. When applied to the {112} slip plane in hcp materials, our approach predicts that a stable stacking fault occurs, associated with a slip of 1/6 (11 ) ≡ ½ (c + a). This is consistent with the ed…
Abstract Triethoxy(alkyl)silanes containing 12—18 carbon atoms in the alkyl groups were hydrolyzed and polycondensed to form ordered structured materials. The XRD pattern of each condensed product showed sharp diffraction peaks with higher orders. The basal spacings approximately corresponded to twice the extended mol…
A new ray picture model based on the multiple interference of light waves in dielectric resonant grating–waveguide structures is presented. The model clearly elucidates the phase relationship between the incident plane wave and the waves diffracted from the resonant grating structure that is responsible for the interf…
A novel chemical reaction to minimize termination reactions in radical polymerization is applied for the first time to the growth of thin polymer films on silica. A living polyacrylamide thin film is grown from a self-assembled benzyl chloride monolayer on silica gel using Cu(bpy) 2 Cl to control the radical populatio…
Nanocrystalline diamond films have been synthesized by microwave plasma enhanced chemical vapor deposition using N2/CH4 as the reactant gas without additional H2. The nanocrystalline diamond phase has been identified by x-ray diffraction and transmission electron microscopy analyses. High resolution secondary ion mass…
We have used x-ray scattering to measure the structure of the passive oxide film formed at high anodic potentials on Fe(110) and Fe(001). The crystalline film has a small crystallite size ( $\ensuremath{\approx}50\AA{}$) and is oriented with the substrate. The film structure is based on ${\mathrm{Fe}}_{3}{\mathrm{O}}_…
Zeolites were used as templates to prepare microporous polymer replicas. Phenol−formaldehyde polymers were synthesized and cured within the channel networks of zeolites Y, β, and L. Dissolution of the aluminosilicate framework in aqueous HF yields an organic replica that contains <2% aluminosilicate. The zeolite templ…
We predict in Si/Ge superlattices a dramatic high-temperature suppression of the perpendicular thermal transport. Total internal reflection confines the superlattice modes and significantly reduces the average group velocity at nonzero in-plane momenta. These consequences of the acoustic mismatch cause at high tempera…
Water:ethanol solvent mixtures of differing polarity have been used to tailor the framework and textural mesopores of HMS molecular sieve silicas through an electrically neutral (S°I°) assembly pathway (S° = dodecyl- or tetradecylamine; I° = tetraethyl orthosilicate). Mesostructure assembly from a water-rich solvent m…
Primary and secondary radiation forces result from pressure gradients in the incident and scattered ultrasonic fields. These forces and their dependence on experimental parameters are described, and the theory for primary radiation force is extended to consider a pulsed traveling wave. Both primary and secondary radia…
The compounds Cs 12 [V IV 18 O 42 (H 2 O)]·14H 2 O ( 1a ), K 12 [V IV 18 O 42 (H 2 O)]·16H 2 O ( 1b ), Rb 12 [V IV 18 O 42 (H 2 O)]·19H 2 O ( 1c ), K 9 [H 3 V IV 18 O 42 (H 2 O)]·14H 2 O·4N 2 H 4 ( 1d ), K 11 [H 2 V IV 18 O 42 (Cl)]·13H 2 O·2N 2 H 4 ( 2a ), K 9 [H 4 V IV 18 O 42 (Br)]·14H 2 O·4N 2 H 4 ( 2b ), K 9 [H 4…
The molecular weight distribution (MWD) and its moments are calculated for hyperbranched polymers formed by self-condensing vinyl polymerization (SCVP) of monomers (“inimers”) with the general structure AB*, where A is a vinyl group and B* is an initiating group. The calculated MWD is extremely broad, the polydispersi…