Periodic characteristics of composite membrane permeability

Abstract

The permeability of the microcapsule membrane is one of the important characteristics in evaluating the function of microcapsule. In order to specify the mechanism of the oscillatory permeation of electrolytes through composite membranes, we derived a solution to the equation for the transport phenomena through the membrane composed of different patches arranged in a parallel array of two different elements. This solution was applied to the experimental data for the transport process of phenobarbital through ethylcellulose/polystyrene micro-capsule which has a patch work-like two-phase structure and exhibits an oscillatory permeation. the values of dispersivities for mass and ionic diffusion flows deduced from the experimental data of Ohara et al. (1985) are 4·0 × 10⁻⁴ and 6·0 × 10⁻¹³ cm²/sec respectively for the membrane thickness of 3·5 × 10⁻⁴ cm.