Intercalation and polymerisation of aniline within a tubular aluminosilicate

The intercalation and polymerization of aniline within the pores of a natural tubular Cu2+-exchanged aluminosilicate clay known as halloysite is studied. The mesoscopic clay fibres have internal diameters of approximately 180 Å and lengths of up to 20 µm and can be deposited as films into which aniline is introduced from the vapour phase. The aniline composite was characterized by powder XRD, TGA, EPR, UV-Vis, XPS and IR spectroscopy. The present results confirm the presence of polyaniline on the internal and external surfaces of the halloysite tubes, thus indicating that the composite material could act as a molecular wire. The polyaniline initially sorbed onto the external surfaces is in a reduced state and evolves toward a more oxidized state as the duration of exposure of the film to aniline vapour increases.