An effective approach towards endowing membranes with tunable charge characteristics and large nanopores

Membranes with tunable charge characteristics and suitable nanopores are highly desired for their enormous potentials in specific membrane separation process. Herein, we present an effective approach to achieve this by using PVC-based grafting amphiphilic charged polymers (GACPs) as membrane additives. Non-solvent induced phase separation (NIPS) combined with a non-solvent annealing (NA) method is carried out to fabricate membranes with suitable nanopores. Employing scanning electron microscopy image analysis and PEG rejection tests on the prepared membranes, we observe pronounced shrinkage of pore size from around 10 to 3 nm caused by the NA process. In addition, the results of the zeta potentials and pore size distribution suggest the successful fabrication of membranes with tunable charge characteristics and large nanopores. Furthermore, the significant increase of Na 2 SO 4 rejection from 20% to 80% demonstrates the effectiveness of this approach, which may have giant application potentials in loose nanofiltration (NF).