Effect of Blown Air Temperature on Morphology, Phase Structure, and Filtration Efficiency of PVDF Nanofibrous Mats Produced via Electro-Blowing

Abstract

This study investigates the effects of temperature of pressurized blown airon fiber morphology, porosity, phase structure, and filtration performanceof PVDF nanofibers produced via the electro-blowing method for the firsttime. The blown air heated to 20, 40, 60, and 80 C was utilized during pro-duction. Increasing air temperatureresulted in more homogeneous distri-bution of fibers and defect-free fibrous mats, accompanied by a significantreduction in fiber diameter. A linear relationship between fiber diameterand pore size was observed; as fiber diameter decreased, reducing air per-meability due to smaller pore sizes. FTIR measurements revealed the high-estβ-phase content (82%) in the PVDF-80C sample produced at 80 C. Therise in temperature lowered solution viscosity and surface tension, contrib-uting to improved drawing effect and therefore higherβ-phase content inthe PVDF polymer. Corona discharge treatment further enhanced the sur-face potential, with the finest fibers exhibiting the highest surface charge.The PVDF-80C sample demonstrated the best performance during filtrationtests against NaCl aerosols (PM0.3) at a flow rate of 95 L/min, achieving afiltration efficiency of 98.68% with a pressure drop of 153 Pa. These findingshighlight the critical role of temperature in influencing nanofiber proper-ties and filtration performance.