Preparation of a novel composite material based on a Nafion® membrane and polypyrrole for potential application in a PEM fuel cell

The process of embedding polypyrrole (PPy) on the surface of a Nafion(R) membrane was studied. Three methods of PPy synthesis directly on the membrane surface were compared. The diffusion method based on the separation of monomer and oxidant ( peroxidisulphate) solutions by the membrane to be modified is proposed as the most promising one. The monomer diffuses through the membrane to the oxidant side, where it is polymerized. In this case sulphate is incorporated into the film as a counter-ion. PPy film prepared in this way adheres well to the Nafion(R) surface and shows promising electrochemical activity. The permeability of the composite for monomer in comparison to self-standing Nafion(R) film is reduced significantly. This may be important for the potential application of this composite, especially in a direct methanol fuel cell, as an alternative membrane-electrode assembly ( MEA), particularly with regard to the currently used MEA's permeability for fuel.