Rapid and robust modification of PVDF ultrafiltration membranes with enhanced permselectivity, antifouling and antibacterial performance

Abstract Zwitterionic materials are well known to possess extraordinary water affinity. However, micromolecular zwitterions have rarely been exploited for membrane hydrophilic modification. Herein, novel antifouling and antibacterial polyvinylidene fluoride (PVDF) ultrafiltration membranes with enhanced permselectivity were facilely fabricated through one-step co-deposition of dopamine and a newly synthesized micromolecular zwitterion (DMAPAPS). With the assistance of CuSO4/H2O2-triggered oxidation, a uniform and hydrophilic coating (water contact angle = 33°) was constructed on membrane surface in only 40 min. The impacts of the DMAPAPS concentration and coating time on membrane performance were investigated. Results showed that our strategy endowed the optimized membrane with high pure water flux of 364 L/m2 ∙ h and BSA rejection of 98.6%. The flux recovery ratios of membrane were as high as 96.3% for bovine serum albumin, 98.1% for humic acid and 95.1% for sodium alginate after 3-cycle filtration, respectively. Moreover, the membrane displayed superior antibacterial activity towards E. coli and S. aureus as well as excellent chemical and mechanical stability. This work provides a versatile platform for the robust, time-saving and cost-effective fabrication of antifouling and antibacterial membranes.