Poly(ethylene oxide)/NH~+_4-smectite nanocomposites

摘要

New materials based on the intercalation of poly(ethylene oxide), PEO, into homoionic NH~+_4-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 T_d symmetry of the ammonium ion. Intercalation of PEO into NH~+_4-hectorite produces a material with regular stacking of the clay layers, but in PEO/NH~+_4 montmorillonite, the layers appear to be irregularly stacked with PEO chains arranged in double layers. However, by exchanging NH~+_4 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 200dej.C are in the order of l0~-7 S/cm.