Effects of nano-sized BaTiO3 on microstructural, thermal, mechanical and piezoelectric behavior of electrospun PVDF/BaTiO3 nanocomposite mats

Polyvinylidene fluoride (PVDF) is a good candidate for use in wearable electronics due to its flexibility, ease of processing, and ability to generate electrical charge in response to applied mechanical stress. In this work, low-density polyvinylidene fluoride (PVDF) nanocomposites containing nano-sized BaTiO3 with cubic symmetry were fabricated by electrospinning process, aiming to generate dominant electroactive β polar phase. The influence of nano-sized filler content on the microstructure, total degree of crystallinity, β phase content, and piezoelectric properties of the electrospun PVDF/BaTiO3 nanocomposites was systematically studied. The crystallinity and the thermal stability were evaluated using differential scanning calorimetry (DSC), x-ray diffraction (XRD) and thermogravimetric analysis (TGA). The content of evolved piezoactive β phase was determined by FTIR spectroscopy. It was shown that the electrospinning process is primarily responsible for very high content (up to 99.4%) of the developed piezoactive crystalline phase. High degree of crystallinity (up to 56.4%) was determined in PVDF/BaTiO3 nanocomposites, confirming the nucleation ability of the nanofiller. Maximum tensile strength of 55.5 MPa (127% higher than PVDF nanofiber mat) and maximum d33 coefficient of 18 pC N−1 were determined for the nanofiber mat containing 20 wt% BaTiO3. We believe that this work provides an important insight into the nanoparticles' distribution and their agglomeration (SEM and TEM analyses) influence on the final properties of PVDF/BaTiO3 webs, generated via electrospinning.