SOLVATION PHENOMENA IN POLYVINYLFERROCENE FILMS - EFFECT OF HISTORY AND REDOX STATE

The water content of electrochemically deposited polyvinylferrocene films was studied using the electrochemical quartz crystal microbalance. Unhydrated films were introduced into aqueous sodium perchlorate solution. Using cyclic voltammetry, the mass and charge change accompanying electrochemical cycling between oxidized and reduced states was determined. During the first oxidation cycle, water uptake into the unhydrated film is triggered after ca. 40% conversion. Of the water taken up during the first cycle, about 50% is retained upon reduction. The water expelled during reduction is reversibly taken up during the next oxidation cycle. Loss and gain of water during subsequent cycling is chemically reversible. After the first oxidation half-cycle, water uptake/loss is linearly correlated with charge transfer in either direction.