Scaling Relation between Electrical Conductivity Percolation and Water Diffusion Coefficient in Sodium Bis(2-ethylhexyl) Sulfosuccinate-Based Microemulsion
Scaling Relation between Electrical Conductivity Percolation and Water Diffusion Coefficient in Sodium Bis(2-ethylhexyl) Sulfosuccinate-Based Microemulsion
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双(2-乙基己基)磺基琥珀酸钠微乳液电导率渗流与水扩散系数的标度关系
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发表时间：
2003
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通讯作者：
N. Nakamura
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作者：
H. Kataoka;T. Eguchi;H. Masui;K. Miyakubo;H. Nakayama;N. Nakamura
采用阻抗谱和脉冲梯度自旋回波（PGSE）核磁共振技术研究了由丁二酸二（2-乙基己基）酯磺酸钠（AOT）、D2 O和癸烷组成的油包水（W/O）微乳液的电导逾渗机理。电导率（σ）随温度（T）和水滴体积分数（Φ）的变化在室温附近有明显的增加。PGSE NMR测量表明，水扩散系数（Dwater）是σ的原因，这意味着主要的电荷载体是溶解在水中并随水迁移的阳离子物质（Na+）。本文首次证实了约化电导率σTΦ-1与Dexchange之间的定量标度关系，即当-10.7 ≤ log（Dexchange）时，σT Φ-1 <$（Dexchange）β [β = 3.2]的渐近行为，其中Dexchange和Ddroplet分别是水滴间和整个宿主水滴的水交换扩散系数。
We investigated the conductivity percolation mechanism of a water-in-oil (W/O) microemulsion composed of sodium bis(2-ethylhexyl) sulfosuccinate (AOT), D2O, and decane using impedance spectroscopy and the pulsed-gradient spin-echo (PGSE) NMR technique. The electrical conductivity (σ) measured as a function of temperature (T) and the volume fraction (Φ) of water droplets show a marked increase near room temperature. The PGSE NMR measurements show that the water diffusion coefficient (Dwater) is responsible for σ, implying that the main charge carrier is the cation species (Na+) dissolved in and transported with water. Given the relation Dexchange ≡ Dwater − Ddroplet, where Dexchange and Ddroplet are diffusion coefficients for the exchange of water between water droplets and for the whole host droplet, respectively, a quantitative scaling relation between reduced conductivity σTΦ-1 and Dexchange was first confirmed to show asymptotic behavior in which σTΦ-1 ∼ (Dexchange)β [β = 3.2 for −10.7 ≤ log (Dexchange...