Polyvinylidene Fluoride Based Breathable Membraneswith Core–Sheath Structure for Multifunctional PiezoelectricSensors

The widespread practical applications of piezoelectric fluoropolymer-based materials are hampered by low piezoelectric coefficients (d33) and complex polarization processes. Herein, the biomimetic core–sheath structure constructed through the electrostatic self-assembly process enables the dipoles of polyvinylidene fluoride/glycine hydrochloride (PVDF/Gly-HCL) fibers to form a long-range ordered distribution via the interfacial suppressing effect. This effect significantly improves the piezoelectricity. PVDF/Gly-HCL fibers doped with 0.5 wt % Gly-HCL not only have ultrahigh β-phase content (Fβ = 98.2%), but also have the highest d33 (67.4 pm V–1). In addition, when the external force field is increased, the fibers show a macroscopic orientation distribution. Additionally, the optimized PVDF/Gly-HCL breathable membranes are capable of a fast response time (24 ms), high sensitivity (1.73 V kPa–1), long-term stable durability (about 10,000 cycles, <2% fluctuation), and excellent breathability. This work provides a scalable and universal road for the preparation of flexible, breathable, and high-performance PVDF self-powered sensing systems.