Crystallinity and Chain Conformation in PEO/Layered Silicate Nanocomposites

The polymer chain conformation under confinement and the morphology of the nanohybrid materials are investigated in hydrophilic polymer/layered silicate nanocomposites. A series of poly(ethylene oxide)/sodium montmorillonite hybrids were synthesized utilizing melt intercalation with compositions covering the complete range from pure polymer to pure clay. Intercalated nanocomposites with mono- and bilayers of PEO chains are obtained in all cases. The intercalated chains as well as the ones adsorbed on the outer surface of the clay particles remain purely amorphous; their conformation, however, exhibits different characteristics from those of the amorphous neat polymer melt. It is only for compositions where a large amount of excess polymer exists outside the completely full galleries that the polymer crystallinity is recovered.