Enhanced Filtration Performance of Hollow Fiber PVDF Membranes with Selective Pore Size Control via Modified NIPS Method

The production of PVDF hollow fiber membranes via the non-solvent induced phase separation (NIPS) method is one of the most straightforward and cost-effective techniques. However, conventional NIPS processes often struggle to achieve a narrow pore size distribution, limiting their performance in precision ultrafiltration applications. In this work, we present an enhanced NIPS approach that enables fine control over the membrane's limiting pore size. By carefully tuning the composition of the spinning solution and optimizing processing parameters, we achieved precise regulation of membrane structure. The resulting membranes exhibited a wide range of well-defined limiting pore sizes—from 80 nm, offering high water permeability (960 L·m−2·h−1·bar−1), down to 10 nm with lower permeability (68 L·m−2·h−1·bar−1). These findings demonstrate the versatility and tunability of the modified NIPS method, enabling the fabrication of PVDF membranes tailored for specific ultrafiltration applications.