Poly(ethylene oxide)/NH4+-smectite nanocomposites

New materials based on the intercalation of poly(ethylene oxide), PEO, into homoionic NH4+-smectites (montmorillonite and hectorite) have been synthesised and characterised. IR spectroscopy of the resultant nanocomposites shows changes in the polymer helical conformation of PEO as well as in the Td symmetry of the ammonium ion. Intercalation of PEO into NH4+-hectorite produces a material with regular stacking of the clay layers, but in PEO/NH4+-montmorillonite, the layers appear to be irregularly stacked with PEO chains arranged in double layers. However, by exchanging NH4+ with Na+ ions, the layer stacking becomes ordered. Ionic conductivity of these materials is lower than that of analogous materials containing alkali metal cations. Typical conductivity values measured in a direction parallel to the silicate layers at 200°C are in the order of 10−7 S/cm.