Piezoelectricity Enhancement Investigation of PVDF Micro-Springs Fabricated by Melt Electrowriting

This work demonstrates the controllable fabrication of polyvinylidene fluoride (PVDF) piezoelectric microsprings by melt electrowriting (MEW) with tunable geometrical parameters. By precisely coordinating transverse and rotational motions, the crossing angle and spiral topology of the micro-spring can be programmed with high fidelity. Systematic experiments further reveal that geometry and processing speed strongly affect the electroactive phase fraction of PVDF fibers, which ranged from $\sim 37 \%$ to $\sim 61 \%$, depending on processing parameters. These results highlight a new pathway for optimizing piezoelectricity in PVDF-based complex 3D microstructures through structural programming rather than post-processing treatments.