Materials Literature
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An ionophore assisted metal-ion transport across block copolymer membranes has been used to control the local Ca2+ concentration during precipitation of calcium phosphate in giant block copolymer vesicles.
The hydrothermal crystallization of barium titanate, BaTiO3, has been studied in situ by time-resolved powder neutron diffraction methods using the recently developed Oxford/ISIS hydrothermal cell. This technique has allowed the formation of the ferroelectric ceramic to be followed in a noninvasive manner in real time…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMesotunnels on the Silica Wall of Ordered SBA-15 to Generate Three-Dimensional Large-Pore Mesoporous NetworksJie Fan, Chengzhong Yu, Limin Wang, Bo Tu, Dongyuan Zhao, Yasuhiro Sakamoto, and Osamu TerasakiView Author Information Department of Chemistry, Fudan University…
Using tapping mode atomic force microscopy, we visualized in direct space and time resolved the changes in viscoelastic properties during crystallization and melting of polyethyleneoxide in 12 nm spheres of a block copolymer mesophase. All spheres crystallized individually and independently, randomly distributed spher…
Free energy and entropy are examined in detail from the standpoint of classical thermodynamics. The approach is logically based on the fact that thermodynamic work is mediated by thermal energy through the tendency for nonthermal energy to convert spontaneously into thermal energy and for thermal energy to distribute…
We investigate the physical foaming process of glassy poly(ether imide) and poly(ether sulfone) using carbon dioxide and report temperature−concentration diagrams (“foam diagrams”) marking out the foaming envelope in which dense CO 2 -saturated films expand and microvoids are introduced. Two types of porosities are ob…
We present a two-dimensional lattice gas with anisotropic interactions which model the known properties of the surface reconstructions of CdTe and ZnSe. In constrast to an earlier publication [12], the formation of anion dimers is considered. This alters the behaviour of the model considerably. We determine the phase…
The effect of low magnetic fields on the magnetic and electrical transport properties of polycrystalline samples of the phase separated compound La$_{0.5}$Ca$_{0.5}$MnO$_{3}$ is studied. The results are interpreted in the framework of the field induced ferromagnetic fraction enlargement mechanism. A fraction expansion…
A detailed study of the supramolecular organization of two series of peptide-based diblock oligomers is reported. The diblock oligomers are comprised of an α-helical oligopeptide rod, which is either based on γ-benzyl- l -glutamate or ε-benzyloxycarbonyl- l -lysine, and a short oligo(styrene) coil. The unique feature…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis of Monodisperse Nanoparticles of Barium Titanate: Toward a Generalized Strategy of Oxide Nanoparticle SynthesisStephen O'Brien, Louis Brus, and Christopher B. MurrayView Author Information Department of Applied Physics and Applied Mathematics 200 SW Mudd Buil…
The ability to generate homogeneous particulate thin films of highly oriented and highly porous microparticles of a post transition metal oxide onto polycrystalline and single-crystalline substrates, at low cost, by a template-free, aqueous low-temperature coating process is demonstrated by the fabrication of a large…
Structure−property relationships of aligned block copolymer lamellae in the vicinity of the order−disorder transition are studied by a combination of optical birefringence and rheology. Minimizing defect density was a crucial part of our experiments. The organization of block copolymer chains into aligned lamellae lea…
INTRODUCTION Reinforcement of polymers with a second organic or inorganic phase to produce a polymer composite is common in the production of modern plastics. Polymer nanocomposites (PNCs) represent a radical alternative to these conventional polymer composites [1-5]. The most noteworthy effort in the last 15 years ha…
Porous organosilica materials have been synthesized by co-condensation of bis(triethoxysilyl)ethane and N -(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS) under acidic conditions. Cetyltrimethylammonium chloride was used as a porogen using the surfactant template method. Formation of the mesoscopic composite was…
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTAcceleration of Polyacrylamide Photopolymerization Using Lyotropic Liquid CrystalsChristopher L. Lester, Shannon M. Smith, and C. Allan GuymonView Author Information Department of Polymer Science, University of Southern Mississippi, Hat…
Ketopantoate reductase (KPR, EC 1.1.1.169) catalyzes the NADPH-dependent reduction of ketopantoate to pantoate on the pantothenate (vitamin B(5)) biosynthetic pathway. The Escherichia coli panE gene encoding KPR was cloned and expressed at high levels as the native and selenomethionine-substituted (SeMet) proteins. Bo…
Abstract Due to the spatial extent of the 5 s and 5 p filled orbitals of lanthanide ions, the shielding of the nuclear charge is not perfect at close distances to the ion. Thus, ligand atoms should experience different effective charge depending upon their distance to the central ion. Using electrostatic arguments and…
Abstract Surface modification of polymers by pulsed plasma has been investigated to minimize degradation reactions occurring at the same time as the surface modification reactions. The hydrogen radical, ion, and electron concentrations in the hydrogen plasma were simulated as a function of the elapsed time after turni…
Photoemission from highly oriented pyrolytic graphite reveals two C $1s$ components separated in binding energy by 120 meV. The high binding-energy component is ascribed to atoms in the outermost atomic layer and the other to deeper layers. The interpretation is based on the low relative intensity observed for the low…
I consider a brush consisting of dendritic polymer end-grafted by its initial segment to a flat, impenetrable surface, in both the molten and solvated cases. The parabolic profile of linear grafted brushes is maintained, but the distribution of the free tips is quite different from the linear brush case. In particular…