Polarized Raman Measurements of Structural Anisotropy in Uniaxially Oriented Poly(vinylidene fluoride) (Form I)

The anisotropic scattering properties of a uniaxially oriented filament of planar zigzag (form I) poly(vinylidene fluoride) have been investigated by polarized Raman scattering measurements. Results indicate that the assignment of the observed bands to specific symmetry species is straightforward and suggest that IR and Raman bands previously assigned from studies on drawn films should be reexamined. Comparison of these new assignments with those calculated from existing valence force fields gives a reasonable agreement but suggests that the force field could be improved by refinement incorporating these latest results. In addition, the observation of a low-frequency Raman active longitudinal acoustical mode and the correlation of its frequency with the crystalline stem length obtained from small-angle X-ray scattering and crystallinity measurements are shown to reflect the trans planar conformation of form I. © 1986, American Chemical Society. All rights reserved.