Piezoelectric properties of PVDF/PLA blends prepared by melt processing and electrospinning

Understanding how polymer blending and processing routes influence the piezoelectric performance of PVDF is crucial for designing high-performance flexible sensors and energy harvesters. In this study, the effect of incorporating polylactic acid (PLA) and varying the processing method on the β-phase content, crystallinity, and piezoelectric response (d₃₃) of PVDF-based materials is investigated. Melt-processed PVDF/PLA blends (5% and 40% PLA) exhibited distinct morphologies, from beaded to co-continuous structures. While PLA addition did not significantly alter overall crystallinity, the β-phase fraction decreased sharply at 40% PLA. After poling, the stretched 95/05 blend showed a 34-45% lower d₃₃ than pure PVDF despite similar β-phase fractions, due to permittivity differences that concentrated the poling field in PLA domains and stretching-induced voids, reducing the effective field in PVDF. The 60/40 co-continuous blend displayed no measurable d₃₃ because α-phase predominated, likely caused by insufficient stress transfer to PVDF during stretching. Electrospinning increased both crystallinity and electroactive phase content compared with stretched films. PVDF electrospun membranes exhibited a 30% higher d₃₃ than their stretched counterparts. However, PVDF/PLA 95/05 electrospun membranes showed no piezoelectric response, likely due to small PLA domains disrupting local electric fields, hindering PVDF chain alignment, and enhancing interfacial interactions that prevent chain rotation during poling. Overall, composition and processing route govern the piezoelectric performance of PVDF/PLA systems, demonstrating that β-phase presence alone does not guarantee functional piezoelectricity.

The online version contains supplementary material available at 10.1007/s44493-026-00010-9.