Controlled Microporous PVDF Membrane Structure Tailored With Sacrificial Layer for Microfiltration Process

This work aims at developing a novel approach to fabricate symmetric porous PVDF membranes using controlled phase inversion technique. In this regard, two approaches have been adopted to make symmetric porous PVDF membranes; namely, vapor‐induced phase separation (VIPS) and co‐casting. In the latter approach, a sacrificial layer of PVP has been deposited on top of PVDF membranes to restrict the diffusion of nonsolvent during phase separation process. It was observed that the pore size distribution in VIPS membranes was relatively narrow, and their permeability was low. Conversely, the co‐casting approach offered a wider processing window for precise control over the structure of membranes from conservative to highly permeable ones. The co‐cast membranes were relatively more porous (81%–89%) and showed enhanced water flux. Optimized conditions for co‐casting resulted in membranes with both complete bacteria rejection and high permeability. All prepared membranes showed good biocompatibility, as evidenced by the viability of L929 fibroblasts being more than 82%. The findings also confirmed that although VIPS could serve as an efficient method within a limited design range, the co‐casting process was more versatile and reliable in terms of developing membranes for application‐specific microfiltration.