Property enhancement in flexible poly(vinylidene fluoride)-based piezoelectric films with large-area preparation

Poly(vinylidene fluoride) (PVDF)-based film exhibits high degrees of electromechanical coupling, widely applied as flexible piezoelectric sensors, soft robotics, energy harvesters, and actuators. In this article, five different types of PVDF-based piezoelectric films were prepared by the extrusion-casting process. The mechanical, dielectric, ferroelectric, piezoelectric, and electrically induced deformation properties of different films were studied. It is found that the addition of lead zirconate titanate (PZT) can improve the dielectric constant of piezoelectric films. PZT powders modified by titanate coupling reagent (UP-105) can further improve the mechanical and electrical properties of composite films by improving the combination and dispersion of organic and inorganic phases. The addition of boron nitride nanosheets can effectively inhibit the generation of leak current, especially at high temperatures. The piezoelectric coefficients (d(33)) of composite films can reach up to 21pC/N, and its strain ratio is about 0.6% under the electric field intensity of 200 kV/mm.