A PHYSICAL AND SPECTROSCOPIC STUDY OF POLYPYRROLE FILMS CONTAINING TETRASULFONATED METALLOPHTHALOCYANINE AND TRANSITION-METAL EDTA CHELATES

The effect of the incorporated counteranion on the structure and properties of polypyrrole is of fundamental interest. In the present study, polypyrrole films containing tetrasulfonated metallophthalocyanine (MPcTs, M = Co and Fe) and transition metal EDTA (MEDTA, M = Co, Cr, and Fe) counteranions are examined by a variety of techniques including elemental analysis, conductivity, X-ray diffraction, SEM, TEM, EPR and Mossbauer spectroscopy. The conductivity stability of PPyCrEDTA is superior to that of both PPyMPcTs and the well known p-toluenesulfonate system (PPyPTS). TEM studies of PPyCoEDTA reveal some crystallinity. By taking advantage of the presence of paramagnetic and Mossbauer active metal ions, the environment of the counteranion within PPyMPcTs and PPyMEDTA is examined by means of EPR and Mossbauer spectroscopy. The former technique reveals a strong magnetic interaction between the unpaired electrons of the polymer and the paramagnetic metal ion centres, and the origin of this interaction is discussed. Structural models for PPyMPcTs and PPyMEDTA are presented.