Investigation of Ions and Solvent Insertion in Conducting Polymers by ac-Electrogravimetry.

摘要

It is now commonly admitted that anions, cations and solvent are both involved uring the switching between oxidation states of electroactive polymers. Despite the numerous past studies, there are still many remaining questions regarding the kinetics of the species, ions and solvent, transferred during a redox reaction. In fact, in practical applications, especially in fuel cell technology, electrode performances are governed by the rate determining step at which the charges are exchanged. In many cases ions and solvent transfer at the polymer/solution interface has been found to be slower than electron motion which balance them to reach electroneutrality. The usual technique used to investigate these charge compensation processes are1 current and mass responses to a potential scan by means of a potentiostatic arrangement coupled with a quartz crystal microbalance. A new approach is based on the frequency analysis of both current and mass which allows a real dissection: of the-whole process and the separation of the movements of each species. Ac-electrogravimetry, where the usual impedance is simultaneously measured with the mass/potential transfer function; is proposed.