MASS-TRANSFER AND CONVOLUTION .2. IN-SITU OPTICAL BEAM DEFLECTION STUDY OF IONIC EXCHANGES BETWEEN POLYPHENYLENE FILMS AND A 1 - 1 ELECTROLYTE

The optical beam deflection technique (mirage effect) shows unambiguou sly that the ionic compensation of positive charges created in polyphe nylene films on an electrode is affected only by the anion during the whole oxidation process. Use of a new technique of convolution by a fr equency transfer function featuring diffusion in the electrolyte allow s quantitative determination of the amount of exchanged species during cyclic voltammetry. The theoretical relationship between the mirage d eflection and electrical current is derived for a symmetrical binary e lectrolyte exchanging only one ion with the interface, and when both d iffusion and migration feature mass transfer. Measurement of the diffu sion coefficient is possible during any electrochemical experiment by scanning the diffusion layer at various locations. Correction of the p ropagation delay between the electrode and the laser probe is possible with this convolutive approach. This allows the use of in situ optica l beam deflection as a quantitative technique for studying dynamic mas s exchange in complicated systems.