Amplified piezoelectric response with β-phase formation in PVDF blended 3D cotton type nanofibers for osteogenic differentiation

PVDF (Polyvinylidene Fluoride) is a representative piezoelectric polymer, and many studies are being conducted to increase the β-phase, a polar chain structure that exhibits piezoelectricity. Electrospinning is known as an effective method to increase the β-phase of PVDF, and electrospun PVDF fibers are attractive materials that can be widely used in various fields due to their flexibility and high biocompatibility. However, since electrospun fibers are generally manufactured as 2D mats, it is difficult to use them as actual tissue scaffolds. In this study, PVDF was fabricated in 3D form by controlling the relative humidity (RH) during the electrospinning process. When the RH was set high during the electrospinning process, the fibers were manufactured in a cotton-like form. In addition, various post-treatment processes were performed to increase the β-phase, and the analysis showed that the post-treatment was effective in improving the β-phase of PVDF. The 3D cotton-type fibers performed in vitro cell culture experiments using MC3T3-E1 cells, confirming the possibility that they could be applied to tissue regeneration fields such as bone regeneration as scaffolds in the future. The manufactured 3D cotton-type PVDF fiber is expected to be applied not only to bio-scaffold but also to various fields requiring piezoelectricity.