Electrotransport properties and morphology of MF-4SK membranes after surface modification with polyaniline

Abstract

The method of template synthesis is used for the surface modification of MF-4SK membranes with polyaniline. The influence of the time of polyaniline synthesis in the surface layer of a perfluorinated MF-4SK membrane on its morphology and electrotransport properties is investigated. It is established that under the synthesis conditions, a gradient distribution of polyaniline develops across the thickness of the membrane, and as a result of this, an anisotropic composite structure is formed. It is shown that the specific electrical conductivity and the electroosmotic and diffusion permeability exhibit an extremal character as functions of the time of polyaniline synthesis. When the orientation of these composite membranes is changed with respect to electrolyte flow, an asymmetry effect in their diffusion characteristics is found. With the application of the bilayer fine porous membrane model, the modified-layer thickness is estimated, and the determining influence of the difference in absolute values of effective fixed-charge volume densities on the development of the asymmetry effect is found.