CRYSTAL FORM AND MOLECULAR-ORIENTATION OF POLY(VINYLIDENE FLUORIDE) THIN-FILMS PREPARED BY VAPOR-DEPOSITION

The crystal form and the molecular orientation of the poly(vinylidene fluoride: PVdF) thin films made by a vapor deposition method were studied. The structure of the deposited films was characterized by X-ray and polarized infrared analyses. The molecular orientation and the crystal structure in the films could be controlled by the substrate temperature and the deposition rate. For example, the beta form with the molecular orientation parallel to the substrate was obtained when PVdF was deposited onto the substrate kept at -100-degrees-C at a deposition rate of 1 approximately 3 anstrom/s. The alpha form in the film was obtained at a substrate temperature of 25-degrees-C. The molecules in the films tended to align from parallel to perpendicular to the substrate as the deposition rate decreased. In addition, at a relatively slow deposition rate and at a substrate temperature of 120-degrees-C, the films were composed of the gamma form with the perpendicular orientation to the substrate.