Characterization of polypyrrole containing Langmuir-Blodgett films by surface specific techniques

Ferric stearate Langmuir-Blodgett films modified by solid state reaction have been characterized with the purpose of investigating the formation of polypyrrole confined in the ordered structure. We have used X-ray photoelectron spectroscopy and secondary ion mass spectrometry for the chemical analysis of the surface. Such analyses give evidence of the formation of polypyrrole in the modified Langmuir-Blodgett multilayer and allow us to deduce the oxidation state of the polymer. Furthermore, by means of scanning electron microscopy and SIMS imaging, we have studied the morphology and the chemical mapping of the conducting polymer formed in the film. After the solid state reaction, samples exhibit a structure consisting of small clusters with sizes from 50 to 300 nm embedded in a stearic acid matrix. Finally the clusters show a highly conductive behavior if compared with the insulating remaining part of the film, further confirming the formation of the conducting polypyrrole domains.