具有复合结构颗粒的介电相互作用

Dielectric Interaction Between the Particles with Composite Structure

讨论了电流变液分散相固体颗粒采取分层复合结构时可能对电流变效应产生的影响.分析过程基于介电极化理论.给出了电场作用下具有复合结构颗粒间的结合能、失配参数的解析表达式,分析了固体颗粒各层的材料性质、厚度、介电常数等因素变化对颗粒间结合能的影响.讨论显示:尽管复合结构颗粒的电流变液具有较为复杂的失配参数表达式,但与单一结构颗粒的电流变液相比,两者在颗粒间结合能的表现上十分类似,提示了以改善电流变效应为目的而采用复合结构固体颗粒作为分散相的建议缺乏理论依据.同时还发现,颗粒外覆层厚度的变化随介电常数的不同、对颗粒间结合能的影响具有正、逆两种效应.

A model of the interaction between the composite spherical particles in an electrorheological (ER) fluid was formulated. The framework is based on the theory of dielectric polarization. The binding energy and the mismatching parameters between the composite particles under electric field was given as the analytic expressions. The influence for the binding energy as the changes are taken place of the materials property, thickness and the dielectric constant in the different layers of the composite particle was discussed. It is shown that the mismatching parameters of an ER fluid whose disperse phase is formed by composite particles have more complex expression than that of the pure particles, even though, they closely resemble each other on the behaviors of the binding energy. This result points out that there is no theoretical reason for the improvement of the ER effect by taking the composite structure in the particles. It is found that along with the change of the outer layer thickness of the composite particle under the different dielectric constants there are the positive and negative effects about the influence for the binding energy between the particles.