2026/07/01 by Gopi Kompelli, Rolanas Dauksevicius, Šarūnas Svirskas +3
paper · doi:10.1088/1361-665x/ae8cc8
Abstract Progress in additively manufactured piezoelectrics is impeded by environmental, regulatory and scalability concerns related to solvent processing. Hazardous solvents dominate the preparation of polyvinylidene fluoride (PVDF)-based piezocomposites for fused filament fabrication (FFF), which remains underdeveloped compared to solvent-assisted additive electronics technologies. The piezoelectric performance of existing FFF-printed PVDF composites is limited due to moderate ferroelectric ceramic content (≲35 vol%). Solvent-free processing and multi-material FFF of highly ceramic-filled (≳50 vol%) piezoelectric devices are largely underexplored. Herein, we report the fully melt-based fabrication of a flexible lead-free piezocomposite filament, highly filled with barium titanate (BTO) particles at the upper printability threshold (∼55 vol%), enabling FFF of piezoelectric sensors with co-printed graphene-doped electrodes. X-ray microtomography and tensile testing indicate that re-extrusion provides uniform filler dispersion in a soft PVDF copolymer (PVDF-HFP) matrix. The multi-material FFF process is fine-tuned to deliver consistent 3D printing of well-fused ceramic-rich and graphene-doped sheets as indicated by strain-rate strengthening behavior. Adding 8 wt% graphene nanoplatelets yields 1.6 S cm −1 conductivity and −1 ). The achieved maximum values of d 33 (35.4 pC/N) and dielectric constant (108 at 1 kHz) are comparable to or exceed solvent-processed counterparts, aligning with predictions of effective medium models. The 3D-printed vibration sensors exhibit practically usable d 31 -mode sensitivity with high linearity and repeatability, confirming FFF reproducibility. This study establishes a scalable and cost-effective solvent-free process for environmentally responsible material extrusion additive manufacturing of flexible piezoelectric devices, addressing current limitations in composite filling level and processing sustainability.