Abstract: In order to restrain the electrochemical aging of viologens, a polyionccmplex based on poly (m-xylyl viologen dibromide) (m-PXV-Br₂) and polymethacrylic acid (PMAA) was synthesised.Cyclic voltammogram and potential-step tests show that the redox.active sites in the polyion complex have a very good electrochemical stability, that is, no any decrease in peak current was observed even the potential scan lasting 500 Cycles.It was also observed that the electrochemical activity of the film decreases with increase of the film thickness and is in relation with the ionic-strength of supporting electrolyte.The response speed of the film coated on a graghite electrode was 0.18 second with the thickness being 0.875μm.

Key words: Polyviologen, Polyion complex, Chemical modified electrode, Electro-ochomic prorperty