Facile plasma grafting of zwitterions onto nanofibrous membrane surface for improved antifouling properties and filtration performance

To improve the permeability and antifouling properties of filtration membrane, zwitterionic sulfobetaine methacrylate (SBMA) was introduced onto the surface of ethylene vinyl alcohol copolymer (EVOH) nanofibrous membrane (NFM) via facile spray-coating followed by plasma treatment method. Surface chemical compositions, morphology, pore size distribution, roughness, zeta potential, hydrophilicity, permeability, separation performance, antifouling and mechanical properties of the pristine EVOH nanofibrous membrane, plasma treated membrane (PNFM) and the SBMA modified membrane (PZNFM) were systematically characterized and compared. Due to the improved hydrophilicity and antifouling properties, PZNFM showed higher water permeability (i.e. 9426.7 L h−1 m−2, 0.2 MPa), lower bovine serum albumin (BSA) adsorption (i.e. 0.15%), and higher flux recovery ratio (i.e. 95.65%) compared with the original NFM. Meanwhile, the newly prepared zwitterionic membrane can separate and intercept of E. coli, S. aureus and Brevundimonas dimimuta absolutely. The mutiphysical-chemical properties of the membrane allow it to function with synergy between permeability and sterile filtration efficiency for further bacterial separation and interception application. Our work provides a simple and scalable method to fabricate sterile membrane with outstanding performance, highlighting its great potential in sterile filtration.