Constructing dual-defense mechanisms on membrane surfaces by synergy of PFSA and SiO2 nanoparticles for persistent antifouling performance

Abstract Synthetic antifouling membrane surfaces with dual-defense mechanisms (fouling-resistant and fouling-release mechanism) were constructed through the synergy of perfluorosulfonic acid (PFSA) and SiO 2 nanoparticles. During the nonsolvent induced phase separation (NIPS) process, the amphiphilic PFSA polymers spontaneously segregated to membrane surfaces and catalyzed the hydrolysis-polycondensation of tetraethyl orthosilicate (TEOS) to generate hydrophilic SiO 2 nanoparticles (NPs). The resulting PVDF/PFSA/SiO 2 hybrid membranes were characterized by contact angle measurements, FTIR, XPS, SEM, AFM, TGA, and TEM. The hydrophilic microdomains and low surface energy microdomains of amphiphilic PFSA polymers respectively endowed membrane surfaces with fouling-resistant mechanism and fouling-release mechanism, while the hydrophilic SiO 2 NPs intensified the fouling-resistant mechanism. When the addition of TEOS reached 3 wt%, the hybrid membrane with optimal synergy of PFSA and SiO 2 NPs displayed low flux decline (17.4% DRt) and high flux recovery (99.8% FRR) during the filtration of oil-in-water emulsion. Meanwhile, the long-time stability test verified that the hybrid membrane possessed persistent antifouling performance.