| Summary: | 博士 === 國立臺灣大學 === 化學工程學研究所 === 89 === Electrophoresis is one of the basic analytical tools to characterize the surface property of colloid particles, and critical coagulation concentraiton is one of the most important physical properties of a dispersed system. Although both of them have been investigated extensively in the literature, almost all of the relevant results are based on the classic Gouy-Chapman model, that is, charged species are considered as point charges. Often, particles are assumed to be rigid, and have constant surface properties. In the present study, the effects of ionic sizes on the electrophoretic behavior and the critical coagulation concentration of a colloidal dispersion are investigated. The classic analyses conducted on rigid particles are extended to the case where a particle is covered by an ion-penetrable charged membrane layer, which contains both acidic and basic functional groups. Particle of this type includes, for example, biological cells and rigid entities covered by an artificial membrane layer. The results of numerical simulation reveal that the classic point charge model will overestimate the potential distribution, electrophoretic mobility, electrostatic interaction force and energy, and critical coagulation concentration.
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