Characterisation of membrane materials by means of electrochemical impedance spectroscopy

The characterisation of membranes (or porous media) is usually effected with absorption or optic techniques. In most cases these techniques are cumbersome and require expensive equipment. The impedance spectrum obtained with a membrane interposed between two electrodes yielded substantial information on the character (hydrophilic/drophobic) of the membrane and could be used to distinguish between the two types of membranes. This is of importance for example in the affinity of solvent extractants for the membrane where these are used in SLM studies. The inherent characteristics of a membrane, such as its permeability and tendency for polarisation, are important for design purpose where transmembrane transport is concerned.