Lyotropic liquid-crystalline phase of oligo(ethylene oxide) surfactant/transition metal salt and the synthesis of mesostructured cadmium sulfide

Date
2003
Authors
Dag, Ö.
Alayoǧlu, S.
Tura, C.
Çelik, Ö.
Advisor
Supervisor
Co-Advisor
Co-Supervisor
Instructor
Source Title
Chemistry of Materials
Print ISSN
0897-4756
Electronic ISSN
Publisher
American Chemical Society
Volume
15
Issue
14
Pages
2711 - 2717
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
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Abstract

Lyotropic liquid-crystalline (LLC), transition metal salt: oligo(ethylene oxide) nonionic surfactant (CnH2n+1(CH2CH2O)mOH, denoted as CnEOm), systems have been studied by means of diffraction, microscopy, and spectroscopy to elucidate the structural, thermal, and templating properties. In the system, the lyotropic salts of transition metal aqua complexes, such as chlorides and sulfates, are insoluble and do not form a LC phase in CnEOm-type nonionic surfactants. However, the transition metal aqua complexes of nitrates and perchlorates are soluble and form 2D and 3D hexagonal and cubic mesophases. These phases are stable in a very broad range of salt:surfactant mole ratios (1.0 and 3.6). The nitrate salts form a hexagonal mesophase. However, in high nitrate salt concentrations (above 3.2 salt:surfactant mole ratio), the salt crystals are either insoluble or the salt:surfactant mixtures are in a cubic mesophase. The structure and thermal properties of the new system are determined by the solubility of the transition metal salts, the concentration of the salt, and the surfactant type. The LC Cd(H2O)42: C12EO10 mesophase has been reacted with H2S gas to produce solid mesostructured CdS (meso-CdS). The meso-CdS particles are spherical in morphology and are made up of hierarchical organization of 2-4-nm CdS particles. The salt:surfactant LLC systems and the solid meso-CdS have been investigated using polarized optical microscopy, X-ray diffraction, Fourier transform infrared, Fourier transform Raman, and UV-vis absorption spectroscopy, scanning electron microscopy, and transmission electron microscopy.

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Book Title
Keywords
Transition metal salts, Diffraction, Fourier transform infrared spectroscopy, Morphology, Optical microscopy, Surface active agents, Transition metals, Ultraviolet spectroscopy, X ray diffraction analysis, Liquid crystals
Citation
Published Version (Please cite this version)