Enhanced piezoelectric performance of PVDF-based composite films prepared by tape casting for wearable sensor applications

Polyvinylidene fluoride (PVDF) is widely used in flexible sensors due to its excellent mechanical and piezoelectric properties. However, its performance is limited by low β -phase content and poor durability. This research optimizes PVDF-based piezoelectric films by incorporating binary and ternary copolymers, namely PVDF-trifluoroethylene and PVDF-trifluoroethylene-chlorotrifluoroethylene (PTC), using a tape casting and extrusion–calendaring process. A total of 18 blend compositions were evaluated, with a PVDF:PTC ratio of 1:1 identified as the optimal formulation, exhibiting the highest β -phase enhancement and improved ferroelectric response. Structural and electrical characterization was performed using Fourier transform infrared spectroscopy, X-ray diffraction, ferroelectric property testing, and impedance analyses, achieving values up to 250×10 ⁻⁶ C N ⁻¹ . The optimized films demonstrated superior sensing performance, with high output voltage under dynamic finger tapping and strong linearity between the applied force and voltage response. Durability testing showed that the sensor retained >97% of its initial output after 8000 cycles and remained stable up to 11,100 loading cycles, indicating excellent mechanical robustness and long-term stability. Compared with pure PVDF, the optimized composite films exhibited significantly enhanced piezoelectric response, improved β -phase crystallinity, and better signal consistency. Finally, the films were successfully integrated into seamless wearable textiles for real-time motion sensing, demonstrating their applicability in smart sportswear. This study provides a scalable, effective approach to developing high-performance PVDF-based flexible sensors with enhanced efficiency, durability, and wearable compatibility.