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.

Vinyl monomers from soybean, sunflower, linseed, and olive oils were copolymerized with styrene (St), methyl methacrylate (MMA), and vinyl acetate (VAc) to determine the reactivity of biobased monomers in radical copolymerization, as well as their feasibility in emulsion processes for the synthesis of biobased latexes. Radical copolymerization of plant-oil-based monomers is described with the classical Mayo–Lewis equation. Using emulsion (or miniemulsion) polymerization with MMA or VAc, stable aqueous polymer dispersions with latex particles measuring 80–160 nm and containing 3–35 wt % of biobased monomer units were successfully synthesized. The number-average molecular weight of the latex copolymers (20 000–150 000) decreases by increasing the degree of unsaturation in monomers and their content in the reaction feed. The presence of plant-oil-based fragments changes the T_g of resulting copolymers from 105 to 79 °C in copolymerization with MMA and from 30 to 11 °C in copolymerization with Vac. As a result, biobased units provide considerable flexibility (elongation at break of about 250%) and improve the toughness of the normally rigid and brittle poly(MMA). Even a small amount (2–5%) of biobased fragments incorporated into the structure of poly(VAc) significantly improves water resistance and provides hydrophobicity to the resulting polymer latex films. The obtained results clearly indicate that the vinyl monomers from plant oils can be considered as good candidates for internal plasticization of polymeric materials through reducing intermolecular interactions in copolymers.