Facile fabrication of flexible PLA/BFO ferroelectric film for smart piezo sensor and energy storage applications

A biodegradable and flexible composite film that combines mechanical flexibility with robust electrical performance is highly desirable for emerging piezoelectric sensing and energy-storage. In this work, we fabricate free-standing polylactic acid/bismuth ferrite (PLA/BFO) composite films with an approximate thickness of 60 µm. We use sol-gel-synthesized phase-pure BFO nanoparticles as the ferroelectric filler. Crystallinity and microstructural characterization reveal crystalline nature and uniform embedding. Dielectric measurements show, real part of the permittivity increase from 4.5 for pure PLA to 6.1 for the PLA/BFO composite film, while the dielectric loss decreases from 0.03 to 0.02 over a broad frequency range. Polarization-electric field hysteresis demonstrates a substantial enhancement in ferroelectric response, with the maximum polarization rising from 0.49 µC/cm ² for PLA to 4.00 µC/cm ² for PLA/BFO at an electric field of 200 kV/cm. The enhanced ferroelectric and dielectric properties highlight PLA/BFO composite film as a promising candidate for flexible piezoelectric sensors and energy-storage devices.