Infrared spectroscopic ellipsometry study of vinylidene fluoride (70%)-trifluoroethylene (30%) copolymer Langmuir-Blodgett films

We report the studies of the molecular conformation and chain orientations through characterization of the vibrational modes in crystalline Langmuir-Blodgett films of the polyvinylidene fluoride/trifluoroethylene copolymer. The infrared spectra obtained by polarized reflectometry and ellipsometry showed that the ferroelectric phase has predominantly all-trans conformation and the paraelectric phase has predominantly alternating trans-gauche conformation, as in solvent-formed films of the same copolymer. The results showed that the polymer chains are predominantly parallel to the film plane with a random in-plane orientation and most of the ferroelectric phase vibrational mode behaviors are consistent with the published mode assignments. The ferroelectric phase optical dispersion curves in the infrared range were extracted from the data analysis based on a uniaxial model. (C) 2003 American Institute of Physics.