Materials Literature
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The formation of alternating layers of positively charged gold and negatively charged silver colloidal particles on glass substrates via electrostatic interaction is described. The charging of the gold and silver colloidal particles is accomplished by self-assembly of 4-aminothiophenol (4-ATP) and 4-carboxythiophenol…
The thermochromic and solvatochromic properties of a series of fluorene-based conjugated polymers have been investigated. Both poly(2,7-(9,9-dioctylfluorene)) and poly(2,5-(thiophene)- alt -2,7-(9,9-dioctylfluorene)) have revealed interesting chromic properties which, on the basis of theoretical calculations, seem to…
Segment and domain orientation behaviors of a series of poly(butylene succinate) (PBS) –poly(tetramethylene glycol) (PTMG) segmented block copolymers containing different amounts of hard segment were studied with synchrotron small-angle X-ray scattering (SAXS) and infrared dichroic methods. Copolymers used in this wor…
K 2 MnSn 2 Se 6 ( I ), K 2 MnSnSe 4 ( II ), and K 2 Ag 2 SnSe 4 ( III ) were prepared by molten-salt (alkali-metal polyselenide flux) reactions at intermediate temperature (400−520 °C). Their crystal structures were determined by single-crystal X-ray diffraction techniques. Crystal data for I: space group P 4/ ncc, a…
Ce-doped BaTiO 3 (BTO:Ce) thin films prepared on MgO (100) substrates by pulsed laser deposition (PLD) at oxygen pressure of 1.2×10 -3 and 17 Pa have been studied by micro-Raman spectroscopy, x-ray diffraction (XRD) and atomic force microscopy (AFM). The film deposited at lower oxygen pressure has a larger lattice par…
The potential use of novel poly(sulfobetaine) copolymers as antibioadherent coatings was investigated using Pseudomonas aeruginosa as a model microorganism and human macrophages and 3T3 mouse embryonic fibroblasts. Two well-defined statistical copolymers with narrow molecular weight distributions were prepared by grou…
The theory of atoms in molecules (AIM) defines bounded atomic fragments in real space that generate transferable atomic properties. As part of a program that investigates the topological partitioning of electromagnetic properties based on the electron density, we have calculated the exact atomic electrostatic potentia…
We calculate the widths, migration barriers, effective masses, and quantum tunneling rates of kinks and jogs in extended screw dislocations in copper, using an effective medium theory interatomic potential. The energy barriers and effective masses for moving a unit jog one lattice constant are close to typical atomic…
Charged poly(amidoamine) (PAMAM) dendrimers are used to create organic−inorganic hybrid colloids in aqueous solution. The formation of gold colloids upon reduction of a gold salt precursor serves as a model reaction to study the influence of reaction conditions and dendrimer generation on the resulting nanostructures.…
In the light of recent experimental as well as theoretical studies, we summarize our present understanding of polar oxide surfaces and examine fundamental issues regarding their stability. The focus is on the surface atomic configurations (relaxations, reconstructions, non-stoichiometry, etc) obtained under specific p…
Addition–elimination reactions produce the salts of hexanitroisobutene dianions from the potassium salt of 2,2-dinitroethanol and trinitromethane. The picture shows an ORTEP representation of the dianion, which clearly features the isobutyl core and six bound nitro groups.
A multiplex electronic switch on the molecular level has been realized by using a tetranuclear FeII complex of the [2×2] grid type. The four metal ions can be switched stepwise between their high-spin and low-spin states by temperature, pressure, and light, thus representing a triple level, triple switch system as ill…
Microstructural evolution induced by scanned laser annealing (SLA) of Cu interconnects was found to produce unique large-grained “bamboo” grain structures, with bamboo grain lengths up to ten times the linewidth. These bamboo grain lengths are shown to depend on the scan rate and laser power. By comparing results from…
The dominance of synthetic fibers increased in 1997 with a big leap in their share of world fiber demand. After surpassing the 50% mark in 1994, the share of manufactured fibers was 53.4% in 1997 [...
Zwei neuartige Struktureinheiten sind in der Kristallstruktur des Polyphosphids Ag3SnP7 vorhanden: eindimensional unendliche (P7)-Ketten und Ag3Sn-Tetraeder (siehe Bild), die die Ketten verknüpfen und ein seltenes Beispiel für einen Übergangsmetall/Postübergangsmetall-Heterocluster in einer Polyphosphidstruktur sind.
The layer structure in the antiferroelectric, ferrielectric, and ferroelectric phases of a liquid crystal device is reported, together with its electric field-induced deformation. The field-free chevron angle is comparable to the steric tilt angle, but differs significantly from the optical tilt angle. A sharp field t…
A boron-rich sodium boride, formerly known as NaB15, has been subjected to a comprehensive structural reinvestigation using X-ray single-crystal and powder diffraction, low-temperature neutron and electron diffraction, high-resolution transmission electron microscopy, and 23Na solid-state NMR spectroscopy. The results…
A variety of metal complexes of 5,10,15-triphenyl-21-monooxa-corrole 4 have been investigated. This monooxa corrole, where one of the pyrrole ring is replaced by a furan moiety, is synthesized by the alpha-alpha coupling reaction of 16-oxa tripyrrane and dipyrromethane. The single crystal X-ray structure of 4 indicate…
Recent experiments have demonstrated that block copolymers are capable of stabilizing immiscible homopolymer blends producing bicontinuous microemulsion. The stability of these polymeric alloys requires the copolymer to form flexible, nonattractive monolayers along the homopolymer interfaces. We predict that copolymer…
The crystal structure of scainiite, Pb 14 Sb 30 S 54 O 5 , has been solved from single-crystal X-ray data and refined to an R index of 8.9 % based on 3703 unique reflections. The structure is monoclinic C 2/ m , with cell parameters a 51.996(8), b 8.148(1), c 24.311(4) A, β 104.09(1)°, V 9990(10) A 3 , and with Z = 4.…