Microstructure and morphology in the PVDF films doped with BiCl3

Abstract

Polyvinylidene fluoride (PVDF) thick films doped with BiCl3 were fabricated by solvent casting method, and their physical properties were systematically investigated, respectively, by X-ray diffraction (XRD), Fourier transform Infrared (FTIR), and scanning electron microscopy (SEM) in this article. It revealed that the degree of crystallinity increased with the increase of the mass fraction of BiCl3, and the maximum β-phase content was achieved if the mass fraction was 2%. When 2% BiCl3 was added, the films became compact and the character morphology of β-phase of spherulitic crystal was proved by the typical organic material with snow-shaped structures. The experimental results suggested that a complex was formed due to the electric ions ionized by BiCl3 and the free radicals with electric charge, destroyed the structure around the lattice, and returned some free radicals to their original positions, thus enhancing the degree of crystallization of β-phase PVDF. The relative dielectric constant and loss became greater as the mass fraction of BiCl3 increased, but the loss decreased at 2% BiCl3. The relationship between the microstructure and dielectric properties was discussed.