Tailoring Piezoelectricity\nof 3D Printing PVDF-MoS<sub>2</sub> Nanocomposite via In Situ Induced\nShear Stress

3D printing of unique structures\nwith tunable properties\noffers\nsignificant advantages in the fabrication of complex and customized\nelectronic devices. This study introduces a process-microstructure–property-guided\nmanufacturing route to fabricate PVDF-2D MoS<sub>2</sub> piezoelectric\nnanocomposites with tunable piezoelectric properties without having\na postprocess. We control PVDF’s microstructure through direct\nink writing (DIW) 3D printing while tuning PVDF-MoS<sub>2</sub> interfacial\nstrain by controlling rheology and 3D printing parameters, such as\nnozzle size and printing speed. Our approach demonstrates tunable\npiezoelectricity in PVDF-MoS<sub>2</sub>, achieving a 15-fold increase\nin the piezoelectric coefficient (d<sub>33</sub>) at a printing-induced\nshear stress of 6685 Pa. This enhancement arises from the electrostatic\ninteractions between PVDF and MoS<sub>2</sub> and the filler distribution\nand alignment caused by the in situ shear stress in 3D printing, as\nconfirmed by XPS and Raman mapping analyses. Our findings advance\nthe understanding of piezoelectric mechanisms in PVDF-based nanocomposites,\nlaying the foundation for 3D printing of piezoelectric sensors in\nwearable device applications with enhanced performance and customization\ncapabilities.