Electrolyte Dependence of Charge Injection Processes for Electroactive Polymer Films
Abstract
Differences in cyclic voltammetric behavior when using acetonitrile as an electrolyte solvent as compared to water solutions have been reported for redox polymers such as poly(vinylferrocene) (PVF). These differences are attributed to the degree of solvent uptake into the polymer film, activity of anion in the solvent, changes in site-site interaction parameters for the polymer film, and differences in the reduction wave de-swelling process. Solvents penetrate glassy polymers and induce backbone motions of the polymer fibril. In the presence of any low molecular weight liquid, the polymer is swollen, and the free volume increases. The free volume may also change as the result of electrochemical cycling between the neutral and oxidized form of PVF. Reversibility of the charge-injection process for these films varies with the salt and choice of solvent. Cyclic voltammetry and quartz crystal microbalance (QCM) studies of NaCF3SO3 and NaPF6 in acetonitrile show irreversible degradation of PVF with charge capacity decreasing with each cycle and no net increase in mass. Degradation of polymer films by reaction with anions such as CF3So3(-) has been observed. This is contrasted by reversible, non-degrading charge injection processes with these same salts in water solutions. An examination of the nature of the degradation for the polymer polyvinylferrocene (PVF) by the techniques of AC impedance, quartz crystal microbalance gravimetry (QCM), and Phase Detection Microscopy (PDIM) will be presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 15, 1989
- Accession Number
- ADA210787
Entities
People
- Katsuhiko Naoi
- Mary M. Lien
- William H. Smyrl’
Organizations
- University of Minnesota