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Nanostructure Formation (nanostructure + formation)
Selected AbstractsNanostructured thermosets from self-assembled amphiphilic block copolymer/epoxy resin mixtures: effect of copolymer content on nanostructuresPOLYMER INTERNATIONAL, Issue 4 2010Miren Blanco Abstract Nanostructure formation in thermosets can allow the design of materials with interesting properties. The aim of this work was to obtain a nanostructured epoxy system by self-assembly of an amphiphilic diblock copolymer in an unreacted epoxy/amine mixture followed by curing of the matrix. The copolymer employed was polystyrene- block -poly(methyl methacrylate) (PS- b -PMMA). The thermoset system, formed by a diglycidyl ether of bisphenol A-type epoxy resin and diaminodiphenylmethane hardener, was chosen to ensure the miscibility of most of the PMMA block until matrix gelation. Transparent materials with microphase-separated domains were obtained for copolymer contents lower than 40 wt%. In systems containing 20 and 30 wt% block copolymer, the PS block formed spherical micelles or worm-like structures before curing, which were stabilized through curing by the more compatible PMMA block phase. Nanostructured thermoset systems were successfully synthesized for self-assembled amphiphilic block copolymer,epoxy/amine mixtures for copolymer contents lower than 40 wt%. Copyright © 2009 Society of Chemical Industry [source] Donor/Spacer/Acceptor Block Copolymer Containing Poly(2,7-carbazole) and Perylenetetracarboxydiimide SubunitsMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 13 2010Changduk Yang Abstract A straightforward synthesis of a conjugated rod/spacer/rod-type block copolymer containing PCz electron-donor and PDI electron-acceptor blocks is described. Two chromophores are covalently connected through sebacate units as saturated spacer. The resulting donor/spacer/acceptor-type block copolymer (PCz-S-PDI) can be applied to limit charge recombination between donor/acceptor interfaces and to control the scale length of nanostructure formation. PCz-S-PDI was used to produce a solar cell with the power conversion efficiency of 0.004%. [source] Mechanisms of semiconductor nanostructure formationPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003R. S. Goldman Abstract We have examined the formation mechanisms of a variety of semiconductor nanostructures, including phase separation-induced alloy nanostructures and strain-induced self-assembled quantum dots. Using data from cross-sectional scanning tunneling microscopy, in conjunction with X-ray reciprocal space maps, we have developed new models for self-ordering of InAs/GaAs quantum dot superlattices and spontaneous lateral phase separation in InAlAs alloys. These models are likely to be applicable to a wide range of heteroepitaxial semiconductor nanostructures. [source] Dynamics of nanostructure formation using point defects on semiconductors by laser radiationPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2009A. Medvid Abstract Dynamics of nanostructures (nanocones and nanocavties) formation on surface of semiconductors by laser radiation based on Thermogradient effect (TGE) is studied. Nanostructures formation of both nanohills and nanocavities are explained by point defects redistribution in gradient of temperature at the irradiated surface. Study of photoluminescence (PL), atomic force microscopy (AFM) and Raman back-scattering spectra speak in favour of presence of quantum confinement effect (QCE) on the top of nanocones on the irradiated surface of semiconductor single crystals. Aggregation of vacancies under the irradiated surface forms nanocavities. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||