A STRUCTURAL STUDY OF POLY (PARA-PHENYLENE VINYLENE)

X-ray diffraction profiles of highly oriented poly (p-phenylene vinylene) (PPV) samples have been acquired at temperatures ranging from 20 to 700 K. The resulting equatorial data have been analysed using a linked-atom-least-square structure factor refinement algorithm that allows for a more complete characterization of the polymer structure and of its temperature-dependent evolution. The resulting analysis identifies strong librational motions of the phenyl rings, a finding in agreement with recent n.m.r. studies. In additon, thin films of PPV are found to possess measurable equatorial anisotropy with [200] and [110] lattice planes preferentially oriented parallel to the film surface.