Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
In this work, Static piezoelectric measuring tester was used to examine piezoelectric strain constant variations as
function of corona fields; it also introduced XRD experiments were carried out on PVDF films with different corona
voltage. Such information may be relevant in identifying changes in the degree of crystallinity and crystalline phase
changes that occur during poling process. Complementary information was also obtained by performing differential
scanning calorimetry (DSC) studies of the same samples. The results show that the poled films exhibit better
piezoelectric properties than non-poled ones due to structural changes during corona poling process. A decrease in the
degree of crystallinity is found and better piezoelectric characteristics can be obtained in poled β-phase films. However,
the value of piezoelectric strain constant of poled α-phase films was relative lower in comparison with β-phase ones due
to existence of a considerable number of non-polar phase content in crystalline region.
Thin oriented films of α phase PVDF were prepared by vacuum evaporation method. The technique of X-ray Diffraction and FTIR were used to analyze the crystalline microstructure of two types of α-form film. The thin oriented films have single pure α phase and the preferred crystalline orientation is on the (020) orientation paralleling to the substrate. The effect of electric field on crystal form of PVDF films during deposition has been studied in the presence of electric field during deposition process, in which the orientation is perpendicular to substrate. The diffraction pattern of PVDF shows that the intensity of diffraction peak decreases with the increase of DC voltage value, and increases with the increase of AC voltage value. The magnitude and direction of electric field have remarkable effect on crystal growth.