ELECTRODISSOLUTION OF POLY(2,5-DI-(2-THIENYL)-PYRROLE) IN ORGANIC ANDHYDROORGANIC MEDIA

Oxidized poly (2,5-di-(2-thienyl)-pyrrole) (poly(SNS)) films on Pt wer e reduced in common organic solvents under chronopotentiometric condit ions. Electrodissolution was observed during reduction, being followed by ultramicrogravimetry. Thin films give an overall electrodissolutio n in 0.1 M LiClO4+acetonitrile solutions. The ratio between charges co nsumed during polymer stripping and those spent for its electrogenerat ion was 0.22-0.28. Between 0.24 and 0.34 electrons per monomeric unit were found to be required to electrodissolve the polymer, The electror eduction of oxidized poly(SNS) was also studied in aqueous mixtures of DMF, acetonitrile, acetone or methanol, containing 0.1 M LiClO4. In t he water-rich regions, a constant weight loss of about 20% was always found, corresponding to the percentage of perchlorate ions lost during the electroreduction process, as confirmed by elemental analysis. Ins oluble fractions of reduced poly(SNS) obtained in hydro-organic media contained small oligomers, from the dimer to the octamer, as detected by mass spectrometry-fast atom bombarding (MS-FAB). Scanning electron microscopy (SEM) micrographs of deposits produced in a 0.1 M LiClO4 aq ueous solution showed that reduced polymer films are spongy.