Rotenberg B, Cadéne A, Dufrêche J-F, Durand-Vidal S, Badot J-C, Turq P
Laboratoire Liquides Ioniques et Interfaces Chargées (UMR CNRS 7612), Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France.
J Phys Chem B. 2005 Aug 18;109(32):15548-57. doi: 10.1021/jp051586k.
A simple two-state model is proposed to explicitly derive the ionic contribution to the frequency-dependent dielectric permittivity of clay. This model is based on a separation of time scales and accounts for two possible solvation modes (inner/outer-sphere complexes) for ions in the interlayer spacing and a possible chemical exchange between both forms. The influence on the permittivity of thermodynamic (distribution constant K(d)) and dynamic (diffusion coefficient, chemical relaxation rate) parameters is discussed. In turn, this model is used to analyze experimental data obtained with Na-montmorillonite for two relative humidities. The values of the parameters extracted from these measurements, and their variation with water content, show that the proposed model is at least reasonable.
提出了一个简单的双态模型，以明确推导离子对粘土频率相关介电常数的贡献。该模型基于时间尺度的分离，考虑了层间间距中离子的两种可能溶剂化模式（内/外球络合物）以及两种形式之间可能的化学交换。讨论了热力学（分布常数K(d)）和动力学（扩散系数、化学弛豫率）参数对介电常数的影响。反过来，该模型用于分析在两种相对湿度下用钠蒙脱石获得的实验数据。从这些测量中提取的参数值及其随含水量的变化表明，所提出的模型至少是合理的。
