Enhanced β-Phase in Direct Ink Writing PVDF Thin Films by Intercalation of Graphene

This research work reports on development and characterization of polyvinylidene fluoride (PVDF) thin films by intercalation of graphene during direct ink writing process with auxiliary electric potential (voltage). The effects of graphene additive on the crystallinity and β-phase transformation in PVDF thin films are studied. The results show that small amount of graphene additive in the writing ink promotes the crystalline nucleation, and the micro electric fields among graphene sheets also promote the formation of the folded β-PVDF chains and prevent the spherulite growth. When 0.05 wt% amount of graphene was added in the writing ink, the crystallinity of the thin film was about twice higher than that of the pure PVDF thin film, and the β-phase content in the thin film reached 67.30%. The sensitivity of the PVDF/graphene composite film is also much higher than that of the pure PVDF piezoelectric film.