Antifouling high-flux membranes via surface segregation and phase separation controlled by the synergy of hydrophobic and hydrogen bond interactions

Abstract

Poly (ether sulfone)/Polyvinyl formal ultrafiltration membranes (PES/PVFM membranes) were fabricated via the synergy of surface segregation and non-solvent induced phase separation (NIPS). PES was utilized as bulk membrane materials and PVFM was utilized as surface segregation modifiers (SSM). The phase separation of PES and the surface segregation behavior of PVFM were controlled by the hydrophobic and hydrogen bond interactions between PES and PVFM. On one hand, the strong interactions delayed the phase separation of PES and promoted the development of membrane pores, increasing the membrane fluxes remarkably. On the other hand, the strong interactions anchored hydrophilic PVFM on the membrane surfaces, endowing the membranes durable antifouling performance. The hydrophobic interaction was estimated by Guerout-Elford-Ferry equation and the hydrogen bond interaction was confirmed by Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC). The structures of PES/PVFM membranes were characterized by scanning electron microscopy (SEM) and the gravimetric method. The surface segregation of PVFM was explored by X-ray photoelectron spectroscopy (XPS). The PES/PVFM membranes exhibited high water fluxes (up to 1000Lm−2h−1bar−1), high flux recovery ratio (up to 98%) and stable hydrophilicity (unchanged after incubated in deionized water for 30 days).