POLYPYRROLE AS A SWITCHABLE MEMBRANE - POTENTIAL-DEPENDING PERMEATION THROUGH POLYMER COATED ELECTRODES

Coupling an electrochemical cell with on line mass spectrometry gives us a new method to study the electrochemical and morphological properties of conducting polymers. A composite membrane consisting of a homogeneous film of the conducting polymer, a porous gold electrode and a Teflon membrane serves as the interface between the electrochemical cell and the mass spectrometer. It is found that the permeation rates of volatile and gaseous compounds through the membrane depend on the redox state of the polymer. This is demonstrated for polypyrrole and water/methanol mixtures and is discussed on the basis of structural changes of the polymer.