IN-SITU FTIR-ATR SPECTROSCOPIC INVESTIGATIONS ON THE POLYMERIZATION PROCESS AND THE REDOX BEHAVIOR OF POLY(THIENYLPYRROLE) THIN-FILM ELECTRODES IN AQUEOUS AND NONAQUEOUS SOLUTIONS .1. CHARACTERIZATION OF THE POLYMERIZATION PROCESS IN ACETONITRILE CONTAINING DIFFERENT SUPPORTING SALTS

Using in situ FTIR attenuated total reflection (ATR) spectroscopy, the electrochemical polymerization process of 2,2'-thienylpyrrole monomer in electrolytes containing LiClO4, Bu(4)NClO(4), Bu(4)NBF(4) and Bu(4 )NPF(6) was investigated. Poly(thienylpyrrole) layers with different p hysical properties are produced and the vibrational modes of the IR ab sorption bands are discussed. The thienylpyrrole monomer exhibits diff erent oxidation potentials in different electrolytes, Monomer and elec trolyte adsorption on the electrode/electrolyte interface, chemical an d electrochemical polymerization of the monomer are clearly observable at definite potentials. The maximum of an electronic absorption chang es with the potential and the electrolyte composition. A polymer with a well-defined conjugation length is produced and charge-carrying spec ies (polaron or bipolaron) emerge in the polymer chain. The polymer fi lm undergoes a change from the non-conducting form to the conducting f orm at higher positive potentials. The results show the capability of in situ FTIR-ATR spectroscopy for yielding important information on th e elucidation of the polymerization reactions of the thienylpyrrole mo nomer.