Enhanced β-crystalline phase in poly(vinylidene fluoride) films by polydopamine-coated BaTiO3 nanoparticles

• PVDF films doped with polydopamine-coated BaTiO3 nanoparticles (BT-Pdop NPs) were simply prepared.
• BT-Podp NPs presented better dispersity in PVDF matrix than BT NPs.
• Higher fraction of β-phase ca. 94.4% in PVDF/BT-Pdop can be fabricated.
• The d33 of PVDF/BT-Pdop is 34.3±0.4 pCN−1, ca. 60.3% higher than neat PVDF film.

In this study we provide a simple but effective method to enhance the β-crystalline phase of poly(vinylidene fluoride) (PVDF), in which the polydopamine (Pdop) coated BaTiO3 nanoparticles (BT NPs) were incorporated into PVDF matrix by solution casting. Comparing with the neat PVDF and PVDF containing the BT NPs, the PVDF films containing Pdop-coated BT NPs were more homogeneous and possess more β-phase. More results from the piezoresponse force microscope and d33-meter measurement, confirmed that the proper wrapping of the BT NPs by functional organic ad-layers could improve the dispersibility and accordingly the polar environment favored the formation of the β-phase.