Melt Electrowriting of High-Quality Poly(vinylidene fluoride) Scaffolds Through Optimized Charge-Neutralization Strategy

Abstract

Melt electrowriting (MEW) is an advanced additive manufacturing technique that tames charged molten jets to fabricate well-organized scaffolds with microscale resolution. Beyond poly(ε-caprolactone), the current gold-standard polymer for MEW, other polymers, such as poly(vinylidene fluoride) (PVDF), have also been printed using this technique to better leverage its piezoelectric properties. However, fabricating PVDF scaffolds with both high-precision and high-layers remains challenging. In this study, appropriate printing parameters and processing windows are identified to ensure jet stability, enabling the fabrication of high-layer and complex nonlinear scaffolds. In addition, while charge neutralization is shown to enhance fiber overlay precision, it is found to reduce fiber–fiber adhesion and layer bonding, leading to delamination fractures and a decline in mechanical properties. By increasing the ionized air temperature during charge neutralization, we achieved a refined balance between printing precision and mechanical property, facilitating the fabrication of high-quality PVDF scaffolds. This is a fundamental study that clarifies the methods and provides a demonstration, encouraging researchers to explore alternatives beyond PCL.