Dielectric relaxation in a water-oil-triton X-100 microemulsion near phase inversion.
Dielectric relaxation in a water-oil-triton X-100 microemulsion near phase inversion.
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DOI：
10.1021/la050235u
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发表时间：
2005-08
期刊：
影响因子：
--
通讯作者：
K. Asami
中科院分区：
文献类型：
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作者：
K. Asami
水（10 mM KCl），甲苯和Triton X-100 （40:40:20 wt %）的混合物显示出温度依赖的相位反转。在10hz至1ghz的频率范围内，用介电光谱研究了相变。在37℃以上的温度下，介电弛豫出现在10 MHz左右，这是由于油包水型乳液中的界面极化所致。随着温度的降低，介电弛豫强度在30℃以下急剧增加，并在27℃时达到峰值，这种变化与30℃至26℃之间低频电导率的增加有关，大约增加了3个数量级。介电行为用界面极化的方式解释，其中球形水滴，在连续的油相中排列成阵列，它们通过水键与最近的邻居随机连接。
A mixture of water (10 mM KCl), toluene and Triton X-100 (40:40:20 wt %) shows temperature-dependent phase inversion. The phase inversion has been studied by dielectric spectroscopy over a frequency range of 10 Hz to 1 GHz. At temperatures above about 37 degrees C, dielectric relaxation appeared around 10 MHz, which was due to interfacial polarization in a water-in-oil type emulsion. The dielectric relaxation drastically changed between 30 and 25 degrees C. With decreasing temperature, the intensity of dielectric relaxation increased steeply below 30 degrees C to attain a peak at 27 degrees C, where that change was associated with an increase in low-frequency conductivity by about three orders between 30 and 26 degrees C. The dielectric behavior has been interpreted in terms of interfacial polarization with a percolation model in which spherical water droplets, arranged in array in a continuous oil phase, are randomly connected with their nearest neighbors using water bonds.