New Phases Found in Reverse Micelle Systems with High Concentrations of AOT
學年 102
學期 1
出版（發表）日期 2013-08-01
作品名稱 New Phases Found in Reverse Micelle Systems with High Concentrations of AOT
作品名稱（其他語言）
著者 Lai, Wei-Chi; Lai, Po-Hsiang
單位 淡江大學化學工程與材料工程學系
出版者 Washington: American Chemical Society
著錄名稱、卷期、頁數 The Journal of Physical Chemistry B 117(32), pp.9568-9575
摘要 This paper discusses the phase behavior, rheology, and structure of self-assembled sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelle systems at high AOT concentrations. When the amount of AOT and wo (the molar ratio of water to AOT) were changed, many different phases were found, a fact which is not discussed in the literature. Opaque gel-like phase (phase separation) occurred with high concentrations of AOT in organic solvents without water. When the AOT concentration and wo were increased to 18–72 m and 2, respectively, the samples were gel-like and translucent. Dynamic rheological results indicate that the viscoelastic transition agreed with a multirelaxation time model. Small-angle X-ray scattering (SAXS) results imply that these samples showed a hexagonally close-packed cylindrical structure in which the diameter of a cylinder was 2.5–3.0 nm, depending on the water contents. Moreover, these AOT cylinders self-assembled into fiber bundles with a diameter of 1–10 μm, as determined using a polarized optical microscope. As wo was increased to 2–6 in 72 m AOT samples, similar rheological and SAXS results were obtained. However, a different type of viscoelastic transition occurred, from multirelaxation to single-relaxation, when wo was increased to 7–11. The samples were in the transparent gel-like phase, and the structures determined by SAXS were a combination of hexagonally packed cylindrical and lamellar structure. The close-packed cylindrical structures had larger radii and shorter lengths with increasing wo. Furthermore, when wo was increased to 12, the gel-like phase disappeared and a highly viscous solution was observed. This is because all the cylindrical structures collapsed and transformed into lamellar structures when the amount of water was further increased.
關鍵字
語言 en_US
ISSN 1520-6106 1520-5207
期刊性質 國外
收錄於 SCI EI
產學合作
通訊作者 Lai, Wei-Chi
審稿制度 是
國別 USA
公開徵稿
出版型式 ,電子版,紙本
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