Premium
On the pH Influence on Electrochemical Properties of Poly(pyrrole) and Poly( N ‐methylpyrrole)
Author(s) -
Michalska Agata,
Maksymiuk Krzysztof
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199803)10:3<177::aid-elan177>3.0.co;2-g
Subject(s) - perchlorate , aqueous solution , inorganic chemistry , chemistry , electrochemistry , polypyrrole , electrolyte , pyrrole , deprotonation , polymer , chloride , supporting electrolyte , ion , electrode , organic chemistry
The electrochemical behavior of poly(pyrrole) doped with chloride (PPy/Cl) and dodecylsulfate (PPy/DS) ions as well as of poly( N ‐methylpyrrole) doped with perchlorate anions (PMPy/ClO 4 ) was studied in aqueous electrolyte (KCl) solutions (pH 0.5 to 7). The results indicate that the pH effect is dependent on polymer/dopant system properties, although in general the pH change mostly affects the polymer by the change of solution redox potential. Although the studied polymers exhibit different formal potentials and ion‐exchange properties, open circuit potentials of these films were quite similar. The slope of the open circuit potential dependence on pH was the highest for PPy/Cl, but still much below the value expected for the H + exchange process. The high sensitivity of PPy/Cl films for the pH changes was also observed in impedance measurements. Results obtained for the PPy/Cl system indicate that acidification of the solution favors lower charge transfer impedances. The results of voltammetric studies indicate that conditioning of the PPy/Cl layer in neutral solution is accompanied with deprotonation of the polymer film. This effect was less pronounced for the PPy/DS layers probably due to the inhibiting properties of the surface active doping anions, and was not observed for PMPy/ClO 4 films. This suggests that hydrogen atom connected with nitrogen atom is involved in the discussed processes.