非导电球型粒子悬浮液宽频介电谱——薄双电层理论的计算机模拟

Broadband Dielectric Spectroscopy of Non-conducting Spherical Particle Suspensions——Computer Simulation of Thin Double Layer Theory

以Shilov等提出的带有紧密层表面电导率的非导电球型粒子悬浮液宽频介电弛豫的薄双电层理论为基础,从电动力学角度解释了粒子分散系两种典型介电弛豫(高频和低频弛豫)的机制.在此基础上,利用Mathcad程序将该理论定量程序化并建立了粒子/水相分散系介电谱参数与体系内部相参数的关系.进而利用该程序模拟了溶液浓度、Zeta电位以及分散粒子半径等内相参数对两种弛豫的影响,结合该理论阐述了不同环境下这两种弛豫的变化规律,从而为今后更好地利用这两种弛豫表征纳米至毫米级球形粒子分散系的各相电及界面性质提供了有价值的参考.

On the basis of a thin double layer theory proposed by Shilov et al, the broadband dielectric spectroscopy of suspensions of non-conducting spherical particles including surface conductivity of the stagnant layer, the mechanisms of the two typical dielectric dispersions （high and low-frequency dielectric dispersion） was elucidated in an electrokinetic way. Based on the understanding above, the theory was programmed quantitatively by means of the Mathcad program, and the relationship between dielectric parame- ters and the inner phase parameters of particle/aqueous suspension was established. Then the influences of the inner phase parameters such as electrolyte concentration, Zeta potential and particle radius on both dispersions of non-conducting particle suspension were simulated through this program. Combining with the theory, the regular change of both dispersions under different conditions was interpreted in detail, which provided a valuable reference on better taking advantage of these dielectric dispersions to characterize the electrical properties of constituent phases and interfaces of suspensions of spherical particles with radii ranging from nanometer to millimeter.