高等学校化学学报

高等学校化学学报

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非导电微球悬浊系的介电谱弛豫机制的考察和界面信息的解析

李娇阳, 赵孔双   

  1. 北京师范大学化学学院, 北京 100875
  • 收稿日期:2006-01-06 修回日期:1900-01-01 出版日期:2006-12-10 发布日期:2006-12-10
  • 通讯作者: 赵孔双

Dielectric Spectroscopy of Nonconductive Microspheres Suspensions——Investigation of Relaxation Mechanism and Analysis of Interfacial Information

LI Jiao-Yang, ZHAO Kong-Shuang   

  1. College of Chemistry, Beijing Normal University, Beijing 100875, China
  • Received:2006-01-06 Revised:1900-01-01 Online:2006-12-10 Published:2006-12-10
  • Contact: ZHAO Kong-Shuang

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被引次数

3

摘要： 研究了不同浓度电解质溶液中聚苯乙烯微球悬浊液的介电谱, 发现在40 Hz～110 MHz频率范围内出现了两个明显的弛豫. 在介电模型基础上对弛豫原因的理论分析结果表明, 千赫兹频域出现的弛豫是由粒子附近双电层中对离子的扩散所致, 兆赫兹附近出现的弛豫源于空间电荷在固/液界面的累积. 应用Hanai方法计算出体系内部的相参数, 获得了微球/溶液界面的电信息, 并给出了合理解释. 理论计算结果验证了模型和方法的适用性. 实验采用透析法调制样品, 有效地防止了体系内部粒子二次团聚的发生.

关键词: 聚苯乙烯悬浮液, 介电弛豫谱, 界面极化, 双电层, 表面电导率

Abstract: Dielectric measurement was carried out on the polystyrene(PSt) suspensions in electrolyte aqueous solution with different concentration. A couple of dielectric relaxations were found in frequency range from 40 Hz to 110 MHz. On the basis of dielectric model, theoretical analysis for the mechanism of the two relaxations show that low(kilohertz) and high-frequency(megahertz) relaxation were respectively attributed to the diffusion of counter ions in electrical double layer and to the accumulation of space charges on phase interface. Phase parameters and electric information of the microsphere interior were estimated from the relaxation parameters by using Hanai's equation, and reasonable explication was suggested. The validity of the model and method used in this work have been examined by theoretical calculation.

Key words: Polystyrene suspension, Dielectric relaxation spectroscopy, Interfacial polarization, Electrical double layer, Surface conductivity

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