2003年11月
Colloidal silver iodide: synthesis by a reverse micelle method and investigation by a small-angle neutron scattering study
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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- 巻
- 559
- 号
- 開始ページ
- 103
- 終了ページ
- 109
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/S0022-0728(02)01470-5
- 出版者・発行元
- ELSEVIER SCIENCE SA
Silver iodide nanoparticles were prepared by mixing two microemulsions containing the precursor salts, silver nitrate and potassium iodide. Five values of w = [water]/[surfactant] were used, namely 2, 4, 8, 16, and 32. Transmission electron microscopy (TEM) showed that the nanoparticle diameters were 4-240 nm and increased proportionally with w. The nanoparticles prepared from a microemulsion of w = 2 and 8 showed brown and ocherous colors respectively, while bulk silver iodide powder is pale yellow. The crystal structure was determined by neutron powder diffraction. The composition was estimated to be 25% beta-AgI and 75% gamma-AgI. The super-ionic conductor phase could not be detected at room temperature. The w = 8 microemulsion was examined with small-angle neutron scattering (SANS) in order to study the core-shell structure of the reverse micelles at various temperatures. Measurements were carried out at 20 and 9 degreesC and then at 70 degreesC and finally at 28 degreesC, in order to investigate whether the structural changes were reversible with temperature. The total radius of the micelles, surfactant shell thickness and water core radius decreased with increasing temperature and the changes were reversible with temperature. The particle diameters derived by TEM were generally larger than those estimated from the SANS measurements. This suggested that the silver iodide nuclei formed initially grew to reach a certain size, corresponding to the most thermodynamically stable species in the microemulsion, because of the fast exchange between the water cores. (C) 2003 Elsevier Science B.V. All rights reserved.
- リンク情報
- ID情報
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- DOI : 10.1016/S0022-0728(02)01470-5
- ISSN : 0022-0728
- Web of Science ID : WOS:000186917900017