Facile preparation of highly oriented poly(vinylidene fluoride) uniform films and their ferro- and piezoelectric properties

Uniform active films are highly desirable for electronic applications, but still challenging. This work proposed a convenient and effective approach for the production of uniform oriented PVDF thin films with high content of polar beta-phase by blade shear. The obtained films not only had a smooth surface, but also achieved uniform component distribution. The results revealed that PVDF crystals preferentially oriented perpendicular to the shear direction and the largest relatively beta-phase content was up to 93% calculated from FTIR. It was also found that an appropriate elevated temperature is helpful to the formation of all-trans beta-phase with the aid of shear. The oriented uniform PVDF films showed outstanding switching and piezoelectric properties with a polarization switching voltage as low as 3 V and a relatively small coercive field of similar to 6 MV m(-1). The observed properties may result from the enhancement of crystallinity of the beta-phase and the orientation of crystals. The results suggest that oriented PVDF films can be suitably implemented in the fabrication of electronic devices.