Electrical modulation of the solution pH near polyaniline and its composite electrodes

The pH in the vicinity of a thin conducting polymer-coated electrode was electrochemically modulated without electrolysis of water. A pH modulator was constructed by depositing polyaniline and its composites with polystyrene sulphonate or polyperfluorosulphuric acid (Nafion^®) thin membrane onto the surface of Pt, Au plate or graphite sheet electrodes. Changes in pH were measured directly using an IS-FET pH sensor. The pH changed by two orders of magnitude within several tens of ms near the polyaniline-coated electrode in a solution without hydrogen and oxygen evolution. The rate of ion transfer in the membrane matrix was determined in relation to the proposed analysis of chronoamperometry.