Polypyrrole doped with fluoro-metal complexes: thermal stability and structural properties

Chemically produced polypyrrole powders doped with the fluoro-complexes flu oro-aluminates, fluoro-zirconates, fluoro-titanates and fluorides are synth esized and characterized by both XPS and four-probe conductivity measuremen ts. The results show that the polypyrrole powders produced were doped with fluorides and with fluoro-metal complexes (Zr, Ti, Al) of different coordin ation numbers. Also, a significant incorporation of sulfates originating fr om the oxidant was determined. The relative concentration of the sulfates a nd of the respective fluoro-metal complexes is strongly affected by the siz e of these dopants and much less from their concentration in the solution. The aging process of these polymers is investigated. We have found that the re are two main mechanisms, the oxidation of the polymeric chain by water a nd oxygen as well as the reaction of fluoride ions with low coordination fl uoro-complexes to form stable complexes of higher coordination number. In t he case of polypyrrole powder doped with fluorides, the mobility of these c ounter-ions leads to the formation of gaseous species. Polypyrrole powders doped with fluoro-zirconates and fluoro-titanates exhibit both good stabili ty in contrast to those doped with fluoro-aluminates and fluorides. (C) 199 9 Elsevier Science S.A. All rights reserved.