STUDY ON DIFFUSION OF ELECTROACTIVE SPECIES IN POLYELECTROLYTE POLYETHYLENE-GLYCOL LITHIUM PERCHLORATE BY CHRONOAMPEROMETRY AT A MICRODISK ELECTRODE

The mass transport dynamics of Ferrocene in polyelectrolyte polyethyle ne glycol lithium perchlorate (PEG . LiClO4) was studied by using chro noamperometry at a microdisk electrode. Chronoamperometry is a powerfu l method for the study of mass transport in polyelectrolyte, it has ma ny advantages over the conventional methods at a microelectrode and th e steady-state method at an ultramicroelectrode. By using this method the apparent diffusion coefficient D-app and concentration C-a of the electroactive species, can be estimated from a single experiment witho ut previous knowledge of either one. We have estimated D-app and C-a o f ferrocene in PEG . LiClO4 polyelectrolyte from 25 degrees C to 75 de grees C. The dependence on the concentration of electroactive species was observed. The diffusion coefficients decrease with increasing ferr ocene concentration and decreasing temperature. The mass transport mec hanism is explained, by using a free volume model.