Hydrophobic SiO2 nanoparticle-induced polyvinylidene fluoride crystal phase inversion to enhance permeability of thin film composite membrane

Thin film composite (TFC) membrane can get rid of small molecular contaminants and salts with a very high efficiency, thus exhibiting promising potential for addressing the emerging problem of a clean water shortage. In this work, a new type of TFC membrane was prepared by interfacial polymerization of two monomers (MPD and TMC) on surface of SiO 2 /polyvinylidene fluoride (PVDF) substrate. The maximum flux of 3.16 L m −2 h −1 Bar −1 was achieved for the optimized hydrophobic SiO 2 nanoparticles well dispersed in PVDF substrate, which is 2.6 times higher than that of 1.21 L m −2 h −1 Bar −1 for the commercial cellulose triacetate reverse osmosis membrane. The improved performance of TFC membrane could be attributed to the higher compaction resistance of SiO 2 /PVDF substrate. Further analysis revealed that PVDF crystal phase inversion induced by superhydrophobic SiO 2 nanoparticles obviously enhanced the intramolecular and intermolecular hydrogen bonds between PVDF polymer molecules. Additionally, the narrower finger-like pore size and thicker pore wall of SiO 2 /PVDF substrate also played significant roles in enhancing the compaction resistance of PVDF membrane. This work also provides a proof-of-concept demonstration of high permeability substrates for effective flux enhancement of TFC membranes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 48204.