Development and Optimization of Unsupported PVDF-based Transfer Membrane

The aim of this work was the laboratory-scale reproduction, characterization, and optimization of unsupported PVDF transfer membranes, investigated during the final thesis internship at GVS Filter Technology S.p.A. The first phase of the project involved replicating industrial membranes under controlled laboratory conditions. The fabricated membranes were all tested through a series of physicochemical and functional characterizations, including water bubble point, water flow rate, airflow measurements, water breakthrough tests, scanning electron microscopy (SEM), and protein binding analysis. These characterizations allowed the assessment of the membrane morphology, surface wettability, pore structure, and protein surface interactions. In the second phase, alternative formulations were investigated by varying the polymer and solvent type, with the aim of transferring the production process of the PVDF transfer membrane, from GVS North America to GVS Italy’s plant. Part of this work included developing a suitable peeling process to detach the unsupported membrane from the casting substrate without damaging its integrity, an essential step toward scalable production. Finally, the washing procedure in Western blotting was optimized by applying an alternative protocol that reproduced the process up to the washing step, without carrying out the Western blot itself. The membranes exhibited strong background signals after Ponceau S staining, suggesting suboptimal surface cleanliness. Therefore, the washing steps were systematically modified to reduce nonspecific staining and to improve overall signal quality and reproducibility. Overall, this work contributes to a deeper understanding of the fabrication-structure function relationships of unsupported membranes and identifies practical strategies to enhance both their manufacturability and their performance.