Preparation of PVDF/PVA composite films with micropatterned structures on light-cured 3D printed molds for hydrophilic modification of PVDF

Abstract Polyvinylidene fluoride (PVDF) is widely used in biotechnology due to its excellent biocompatibility, high temperature and pressure resistance, and outstanding mechanical properties. However, the hydrophobic nature of PVDF surface hinders the attachment of biological proteins. In order to enhance the wettability of PVDF surfaces, this study prepared composite films by blending PVDF with polyvinyl alcohol (PVA), and micro-patterned structures were fabricated on the material surface using a mold-replication method based on digital light processing (DLP) photopolymerization printing technology. A series of characterization techniques including surface morphology analysis, chemical composition analysis, and wettability testing were employed. The surface morphology analysis results indicated that the method of using DLP photopolymerization technology to print mold replicas and create micro-patterned structures was indeed effective in creating micro-patterned structures on both PVDF and PVDF/PVA composite films. The chemical composition analysis showed that the spin-coating of PVDF powder material resulted in PVDF β-phase crystalline structure, which has a positive effect on cell growth. Furthermore, the introduction of hydrophilic groups was achieved by mixing PVDF with PVA. Wetting test results indicate that the incorporation of the hydrophilic material PVA and micro-patterned surfaces both contribute to the improved hydrophilicity of the material. The water contact angle of the micro-patterned PVDF/PVA composite film reached 30.8°, exhibiting excellent hydrophilic properties. This study achieved the optimization of PVDF surface properties through micro-patterned surface modification and material composition design, providing novel insights for the further development of PVDF materials in the field of biotechnology.