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Structural Perfection (structural + perfection)

Distribution by Scientific Domains

Polymers and Materials Science	50%
Physics and Astronomy	50%

Selected Abstracts

Monocrystalline Cd0.2Zn0.8Te solid solution obtained by self-selecting vapour growth

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 9 2010
A. Szczerbakow
Abstract Cd0.2Zn0.8Te monocrystals with the sizes of about 15 mm have been produced by self-selecting vapour growth (SSVG). High degree of structural perfection of monocrystalline Cd0.2Zn0.8Te was achieved. Excellent compositional uniformity was observed as well. To our knowledge, no comparable results are reported for this solid solution. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

End-functionalization of semiconducting species with dendronized terpyridine,Ru(II),terpyridine complexes

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 7 2009
Elefterios K. Pefkianakis
Abstract Semiconducting oligomers and polymers decorated with two or one dendronized tpy-Ru(II)-tpy metallocomplexes are presented. Initially, free terpyridine end-functionalized semiconducting oligomers (distyrylanthracene, quinquephenylene, mono- and trifluorenes) were prepared while in a second approach, atom transfer radical polymerization was employed for the preparation of side-chain oligomeric and polymeric (oxadiazole)s using a terpyridine initiator. These terpyridine-bearing oligomers and polymers were complexated with a Percec-type first-generation (G1) dendronized terpyridine,Ru(III)Cl3 monocomplex, having two dodecyloxy groups. All oligomeric and polymeric metallocomplexes were characterized via NMR spectroscopies for their structural perfection and via UV-Vis and PL spectroscopies for their optical properties. The existence of the organic semiconducting blocks in combination with the terpyridine,Ru(II),terpyridine groups afforded hybrid metallo-semiconducting species presenting the optical features of both their components. Moreover, their thin-film morphologies were investigated through atomic force microscopy, revealing, in some cases, an organization tendency in the nanometer scale. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1939,1952, 2009 [source]

Ordering Behavior of Layered Silicate Nanocomposites with a Cylindrical Triblock Copolymer

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2006
Chung Ho Lee
Abstract Summary: The ordering behavior of the nanocomposites of organically modified montmorillonite (OMMT) with a cylindrical triblock copolymer of polystyrene- block -poly(ethylene- co -butylene)- block -polystyrene (SEBS) has been investigated by temperature-resolved small-angle X-ray scattering (SAXS) and rheometry. X-Ray diffraction (XRD) confirms that the polymer chains are successfully intercalated with the interlayer gallery of the silicates. The data obtained from the SAXS and rheological measurements show that the addition of OMMT leads to a change in the microphase separation behavior of SEBS in the nanocomposites. The molecular interaction between OMMT and the polystyrene (PS) chains of SEBS decreases the structural perfection of the self-assembling, phase-separated domain structure of the nanocomposites. Rheological data exhibit that the order-order (TOOT) and order-disorder transitions (TODT) of the SEBS/OMMT nanocomposites decrease with the addition of OMMT. The highest elongation at break is obtained at approximately 2% OMMT and its further addition to the mixture leads to decreases in tensile strength and elongation. The change in the storage modulus (G,) of a) SEBS, b) S98M2, c) S95M5, and d) S90M10, as a function of temperature in the range of 150,,,T (°C),,,260. [source]

X-ray characterization of epi-Ge/Pr2O3/Si(111) layer stacks by pole figures and reciprocal space mapping

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2009
Peter Zaumseil
Abstract An epi-Ge/Pr2O3/Si(111) layer structure prepared by consecutive steps of epitaxial deposition and annealing is used to demonstrate the possibility of a complex characterization by combination of different X-ray diffraction techniques. Especially pole figure measurements, reciprocal space mapping (RSM) and high resolution (HR) ,/2, scans at selected inclined netplanes were successfully used to determine the in-plane lattice orientation of the layers relative to the substrate, the strain state of all layers and the structural perfection of the epi-Ge film. It was found that the major part of the epi-Ge layer has the same type A stacking orientation as the Si substrate, but about 0.6% is of type B. The Pr2O3 buffer layer exhibits type B only. The strain state of oxide and epi-Ge was determined, and a small difference in the lattice constant of type A and B epi-Ge was found. Microtwins lying in inclined {111} planes were unambiguously identified by pole figure measurements as the dominating structural defects in the epi-Ge layer. They cause a characteristic scattering pattern in reciprocal space maps. The proposed combination of X-ray techniques allows a relatively fast, integral and non-destructive analysis of heteroepitaxial semiconductor oxide semiconductor structures. [source]