The impact of nonpolar coagulation bath-immiscible liquid additives on the polyethersulfone membranes structure and performance

Abstract

In this study, the impact of several normal alkanes as additives on the structural parameters and the morphologies of flat sheet PES membranes were investigated. The asymmetric membranes were fabricated by phase inversion method. Also n-hexane, n-decane, and n-tetradecane were used as additives. The effects of different concentrations of these additives were investigated by producing the ternary phase diagrams. Further the membranes were characterized by means of solute transport test, contact angle, pure water flux, porosity measurement, and scanning electronic microscopy. It was expected that two distinct phase inversions to be occurred since both the polymer and the additives were insoluble in the coagulation bath. Observations revealed that n-hexane and n-decane were less effective compared with n-tetradecane in terms of binodal shifting toward PES/NMP axis. In conclusion, it was revealed that the coagulation bath immiscible-liquid additives had a major impact on the membranes structure in order to achieve the enhanced properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44509.