Preparation and electroactive properties of a PVDF/nano-TiO2 composite film

In the present study, poly(vinylidene fluoride) (PVDF)/nano-TiO₂ electroactive film was prepared by coating a substrate with an acetone/DMF solution, which was evaporated at a high temperature (110 °C). The crystallisation behaviour, dynamic mechanical properties and electroactive properties of this PVDF/nano-TiO₂ electroactive film were investigated. The cross-section and surface of the film were observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) results showed that the film containing the PVDF β phase, the desired ferroelectric phase, was obtained by crystallising the mixed solution of nano-TiO₂ and PVDF at 110 °C, while the film containing the α phase was obtained from the crystallisation of the pure PVDF solution at the same temperature. It was found that the storage modulus, the room-temperature dielectric constant and the electric breakdown strength of the composite films were much higher than those of a pure PVDF film. TiO₂ improved the mechanical properties and electroactive properties of the film. The results indicate that PVDF/nano-TiO₂ composite films can be applied to the fabrication of self-sensing actuator devices.