Low-frequency dielectric relaxation of hematite and silica sols
Low-frequency dielectric relaxation of hematite and silica sols
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DOI：
10.1021/la00031a005
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发表时间：
1993-07
期刊：
影响因子：
3.9
通讯作者：
J. Kijlstra;H. P. Leeuwen;J. Lyklema
中科院分区：
文献类型：
--
作者：
J. Kijlstra;H. P. Leeuwen;J. Lyklema
本文讨论了赤铁矿和硅溶胶的低频介电响应。对于这两个系统，这种响应取决于pH值，因此，对表面电荷。从这个响应计算的电动势系统地超过从电泳获得的电动势。这种差异可以通过考虑滑移面内的表面传导来解决。扩展Fixman的理论，表面电导率是明确的，并从电泳和介电数据的组合计算。对于赤铁矿和二氧化硅，结果表明，大部分（移动的）反荷位于滑移面内。这部分随着表面电荷密度的增加而增加。
In this paper we discuss the low-frequency dielectric response of dilute aqueous hematite and silica sols. For both systems this response depends on pH and, hence, on the surface charge. Electrokinetic potentials computed from this response systematically exceed those obtained from electrophoresis. This discrepancy can be resolvedby accounting for surface conduction within the slip plane. Extending Fixman’s theory, the surface conductivity is made explicit and computed from a combination of electrophoretic and dielectric data. For both hematite and silica, the results show that a large fraction of the (mobile) countercharge is located within the slip plane. This fraction increases with increasing surface charge density.