α–β Phase transition induced by self-assembly process of BaTiO3 aggregates in polyvinylidene fluoride composites

Polyvinylidene fluoride (PVDF) exhibits favorable piezoelectric properties for energy storage applications. However, their application has been hindered owing to their low dielectric constant. To overcome this, studies have reported the incorporation of BaTiO3 fillers to induce a phase transition in PVDF to a piezoelectric phase, i.e., the β phase. In this study, the effect of self-assembled BaTiO3 filler aggregates on the α–β phase transition of BaTiO3/PVDF composites was investigated. Through scanning electron microscopy and Fourier transform infrared spectroscopy, we observed that the α–β phase transition of the composites increased as the average secondary particle area of the BaTiO3 aggregates increased. This suggested that dielectric polarization exhibited by the presence of filler/polymer/filler heterointerfaces in the aggregates was significant in the α–β phase transition of the composites.