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Morphology Transformation (morphology + transformation)
Selected AbstractsMorphology Transformation of Hematite Nanoparticles Through Oriented AggregationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2008Lili Wang Hematite nanoparticles 30,45 nm in width and 15,25 nm in thickness were synthesized through oriented aggregation by a hydrothermal method. X -ray diffraction, transmission electron microscopy, high-resolution TEM, selected area electron diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy analyses were applied to characterize the nanocrystals. Morphology transformation of these hematite nanoparticles from irregularly shaped to flower like with the assistance of oleic acid was surveyed. Based on these results, possible formation mechanism of the hematite nanoflowers is discussed here. [source] Atomic Imaging of Phase Transitions and Morphology Transformations in NanocrystalsADVANCED MATERIALS, Issue 48 2009Marijn A. van Huis A newly developed SiN microhotplate allows specimens to be studied at temperatures up to 1000 K at a resolution of 100 picometer (see image). Aberration-corrected transmission electron microscopy has become a commonplace tool to investigate stable crystals; however, imaging transient nanocrystals is much more demanding. Morphological transformations in gold nanoparticles and layer-by-layer sublimation of PbSe nanocrystals is imaged with atomic resolution. [source] Morphology Transformation of Hematite Nanoparticles Through Oriented AggregationJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2008Lili Wang Hematite nanoparticles 30,45 nm in width and 15,25 nm in thickness were synthesized through oriented aggregation by a hydrothermal method. X -ray diffraction, transmission electron microscopy, high-resolution TEM, selected area electron diffraction, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy analyses were applied to characterize the nanocrystals. Morphology transformation of these hematite nanoparticles from irregularly shaped to flower like with the assistance of oleic acid was surveyed. Based on these results, possible formation mechanism of the hematite nanoflowers is discussed here. [source] Synthesis and morphology transformation of amphiphilic diblock polyurethane copolymers in aqueous solutionPOLYMER INTERNATIONAL, Issue 8 2010Qing Miao Abstract Amphiphilic block copolymers possess both hydrophobic and hydrophilic properties and can form versatile micellar structures in aqueous solution. The aim of the research presented was to prepare a series of non-ionic amphiphilic diblock polyurethane copolymers (PUn) based on isophorone diisocyanate, monoallyl-end-capped poly(ethylene oxide) and poly(propylene oxide) (PPO), followed by an investigation of their micellization properties and morphology transformation in aqueous solution. The PUn samples were synthesized by condensation polymerization. These polyurethanes exhibit surface tension as low as 33.7,37.0 mN m,1. There is an obvious decrease in critical micelle concentration as the hydrophobic PPO molecular weight increases. According to transmission electron microscopy, the morphology of aggregates of the copolymers can be tuned by varying the concentration in aqueous solution rather than organic solvent. For example, for PU7, large compound micelles are produced instead of vesicles. For PU17, the concentration can be used to control the size and thickness of vesicles. Vesicle size increases from 60 to 500 nm and vesicle thickness from 40 to 60 nm with concentration ranging from 0.003 to 0.03 wt%. The study shows that the copolymers in aqueous solution have excellent surface activities. In addition, they can self-assemble into large compound micelles or vesicles at certain concentrations. Moreover, the synthesis method described allows one to obtain a desired morphology of aggregates by adjusting the composition of hydrophilic and hydrophobic segments, which provides a novel and simple way to obtain particles on the nanometer scale. Copyright © 2010 Society of Chemical Industry [source] | ||||||||||