Boosting Piezoelectricity by 3D Printing PVDF-MoS2 Composite as a Conformal and High-Sensitivity Piezoelectric Sensor

Abstract

Additively manufactured flexible and high-performance piezoelectric devices are highly desirable for sensing and energy harvesting of 3D conformal structures. Herein, the study reports a significantly enhanced piezoelectricity in polyvinylidene fluoride (PVDF) achieved through the in situ dipole alignment of PVDF within PVDF-2D molybdenum disulfide (2D MoS2) composite by 3D printing. The shear stress-induced dipole poling of PVDF and 2D MoS2 alignment are harnessed during 3D printing to boost piezoelectricity without requiring a post-poling process. The results show a remarkable, more than the eight-fold increment in the piezoelectric coefficient (d33) for 3D printed PVDF-8wt.% MoS2 composite over cast neat PVDF. The underlying mechanism of piezoelectric property enhancement is attributed to the increased volume fraction of β phase in PVDF, filler fraction, heterogeneous strain distribution around PVDF-MoS2 interfaces, and strain transfer to the nanofillers as confirmed by microstructural analysis and finite element simulation. These results provide a promising route to design and fabricate high-performance 3D piezoelectric devices via 3D printing for next-generation sensors and mechanical–electronic conformal devices.