High‐Performance of Piezoelectric and Ferroelectric PVDF ‐TrFE Based Composites Engineered by MWCNTs@BaTiO ₃ Heterostructure

The incorporation of piezoelectric ceramic nanofillers has been shown to effectively promote the formation of piezoelectric phases in PVDF-TrFE polymers, thereby improving both piezoelectric and ferroelectric performance. However, the intrinsic depolarization shielding exerted by the polymer matrix hinders the full polarization of the ceramic phases, thus limiting the improvement of the matrix electrical performance. Here, a novel strategy is proposed by the construction of Multi-walled Carbon Nanotubes (MWCNTs)@BaTiO₃ heterostructures to enhance the polarization of composite films. For the first time, MWCNTs are grown in-situ on BaTiO₃ nanoparticles by chemical vapor deposition, using their local field enhancement to promote dipole alignment within BaTiO₃. With only 5 wt.% of filler, the films exhibit high remanent polarization (14.29 µC cm^-2) and piezoelectric coefficients (61.2 pm V^-1). Notably, the films maintain a robust piezoelectric response (2.45 V) even under non-transient mechanical loading, high-lighting their potential for acoustic sensing applications. Furthermore, the in-situ interface engineering approach mitigates MWCNTs aggregation within the matrix, obviating labor-intensive post-processing steps such as purification or functionalization. These results in a simplified and cost-effective fabrication route. These findings provide a novel strategy for tuning interfaces in ceramic-reinforced piezoelectric systems, contributing to the advancement of high-performance flexible electronics and wearable systems.