writer：Yong Ao, Junjun Yuan, Wenqi Yu, Rui Yuan, Boling Lan, Shenglong Wang, Tingting Zhou, Guicen Liu, Wei Zhao, Zhiyuan Gao, Xiaofei Jiang, Weili Deng, Long Jin, Weiqing Yang
keywords：interfacial polarization，montmorillonite nanosheets，polymer nanocomposites，piezoelectricity enhancement，health monitoring，piezoelectric sensors
source：期刊
Issue time：2026年

Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE), PT) is a promising piezoelectric polymer for flexible electronics, but its output remains insu?cient for reliable health monitoring of subtle motions and vital signs. Conventional strategies employ high-permittivity (high-k) nanofillers to enhance piezoelectricity via interfacial polarization, yet they inevitably increase leakage current and obscure the genuine contribution of interface e?ects. Here, we challenge this paradigm by incorporating low-permittivity (low-k) montmorillonite (MMT) nanosheets into PT. Despite theoretical expectations of reduced permittivity, the large-aspect-ratio MMT creates extensive interfacial regions where permittivity mismatch induces localized polarization, promoting a gauche to all-trans conformational transition in polymer chains as verified by theoretical calculations and experimental characterization. Electromechanical measurements reveal a concentration-dependent enhancement peaking at 4 wt% MMT, achieving an eight-fold increase in voltage and three-fold increase in current compared to pristine PT. The optimized composite is fabricated into flexible sensors that clearly resolve distinct patterns of walking, jumping, squatting, and shoulder asymmetry. This work resolves the apparent paradox between theoretical prediction and experimental performance, establishing low-k two-dimensional materials as a viable and versatile platform for interfacial polarization engineering in high-performance flexible piezoelectric composites