Abstract
X-ray-diffraction studies of highly oriented -phenylene vinylene) (PPV) films before and after vapor-phase or liquid-phase intercalation by have been performed. In both cases the data support a structural evolution dominated by a direct transformation of the original PPV polymer to a single, heavily doped phase. The best-fit model obtained from structure-factor refinements to the -PPV equatorial data is fully consistent with the previously proposed “stage-1” layered structure in which the PPV chains and the sulfate ions form an alternating sequence of cation- and anion-radical layers with a monoclinic unit cell dominated by the PPV placement and lattice parameters of Å, Å, Å, and . Nonequatorial scattering data suggest that at room temperature the layer is not well ordered. Additional data sets probing the anisotropy within the equatorial plane (perpendicular to the PPV chain axis) clearly indicate that the insertion of layers occurs by creating galleries that are parallel to - plane of the PPV host polymer. This direction is effectively perpendicular to the commonly accepted intercalation scheme, which has these layers parallel to the pristine PPV [100] planes.
- Received 24 February 1998
DOI:https://doi.org/10.1103/PhysRevB.58.4089
©1998 American Physical Society