Direct writing of PVDF piezoelectric film based on near electric field added by [Emim]BF4

PVDF/IL piezoelectric film based on [Emim]BF4-added was prepared by near electric field direct writing. The β-phase content and its electric property of the film were analyzed. The results showed that the content of β crystal phase of PVDF film was improved by the synergistic effect of IL ([Emim]BF4) and near electric field. When the amount of [Emim]BF4 added was 1.5 wt%, the relative β-phase content of PVDF film reached 85.09%, and the crystallinity is 47.84%. Increase in [Emim]BF4 content resulted in a significant increase in the relative dielectric constant of the film, from 6 to 285, but also accompanied by a sharp increase in dielectric loss. The d33 value of the film can be as high as −10 pC/N, and the output voltage from the cantilever beam vibration feedback indicates that the voltage strength of the [Emim]BF4-added film is greatly improved compared with the pure PVDF film.