Potentiostatic pulse and impedance investigations of the redox process in polyaniline films

✍ Scribed by O. Genz; M.M. Lohrengel; J.W. Schultze

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 607 KB
• Volume: 39
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(94)80053-7

✦ Synopsis

PAN1 6lms of thicknesses from 0.06 to 7~ were investigated by the potentiostatic pulse method and EIS. The 6hns behaved very similar in respect to both methods over the whole range of thicknesses. The oxidii fIhn can be described as a battery electrode with a specific capacity as high as 130Fcmm3. The series resistance of the oxidized tihn is much smaller than the electrolyte resistance. The reduced 6hn has a high series resistance of about 4kRcm. For the reduced tilm the capacity of the interface metal-polymer is detected in the impedance spectra.

Both impedance spectra and potentiostatic current transients indicate that the oxidation of PANI is an inhomogeneous process. We conclude from our measurements, that the transition follows a sequence of nucleation and growth of conducting zones, perpendicular to the substrate electrode. Partially oxidized polymer tihns can be frozen-in. The impedance spectra of these intermediate states are interpreted on the basis of a geometrical model.