Facile fabrication of reinforced homoporous MF membranes by in situ breath figure and thermal adhesion method on substrates

Abstract

Homoporous membranes are promising for size-sieving filtration, but their prospect is restricted by the lack in mechanical strength. A facile and low-cost route based on in situ breath figure and thermal adhesion method is proposed to fabricate the reinforced homoporous MF membranes in this research. The substrates specific to this route are fabricated by PVDF coating and then ice sealing on nonwoven fabrics. On the tailor-made substrates, the porous film is formed as usual by the breath figure method, and then immobilized on the substrate conveniently by PVDF melting. Acetone is introduced into the casting solution with intent to accelerate solution spreading on ice surface and facilitate micron-scale water droplets floating down to the solution film, so that the resistance layer could be formed thinner and abundant in perforated pores to attain high water permeation flux. Four usually used homoporous membrane materials, i.e., PSF, PES, PPO and PEI, have succeeded in membrane fabrication. FE-SEM images reveal that membrane pores are perforated and homogeneous with controllable size, again the homoporous layer is tightly adhered on substrate. Water permeation, particle sieving and regeneration tests indicate that the reinforced homoporous membranes made by this novel method are practicable for high-resolution separation under moderate pressure and long-time service.