We have studied the synthesis of polypyrrole-clay nanocomposites by the in situ oxidative polymerization of pyrrole in the
interlayer space of vermiculites with different layer charges from Santa Olalla and Ojén, Spain. Moreover, the influence of
different interlayer cations (Na+, Mg2+, Fe3+) on the interaction between pyrrole and the vermiculties was studied. The resulting materials were characterized by means
of DTA-TG, XRD, FTIR and Mössbauer spectroscopy. In all samples polymerization of pyrrole was observed, presumably triggered
by the structural iron. In most cases it was found to be externally deposited. An uptake of pyrrole in the interlayer space
and PPy formation is observed in the case of the Fe3+-intercalated Ojén vermiculite, which has a lower layer charge than the Santa Olalla vermiculite.