Abstract
Polymer/clay nanocomposites have attracted much attention due to their unique mechanical, electrical, optical, and thermal properties. In this study, we have prepared highly oriented PEO/clay nanocomposite films in which the clay platelets stacked perpendicular to film surface. The composite films with different contents of clay were prepared by solvent casting with different solvent removal rates. The orientation of PEO crystal with respect to the clay platelets was then investigated by synchrotron wide angle x-ray scattering (WAXS). From the 2-D WAXS patterns, homeotropic orientation of PEO crystals was observed in the composites prepared by slow solvent evaporation irrespective of clay content and crystallization temperatures. In the films prepared by fast solvent removal, the PEO crystals were found to display homogeneous orientation preferentially. Subsequent shearing treatment of the composite films may shift the homogeneous orientation to homeotropic state.