Microscopic behavior of polyvinylpyrrolidone hydrophilizing agents on phase inversion polyethersulfone hollow fiber membranes for hemofiltration

In some biomedical applications, hollow fiber membranes are highly demanded with desirably asymmetric structures, characterized by a dense selective inner skin with which the blood is in contact and supported by porous outer-layer. In this work, such membranes have been successfully prepared by appropriately adjusting membrane manufacturing parameters. Different molecular weights of polyvinylpyrrolidones (PVPs) were used as the hydrophilizing additives for membrane spinning in order to examine their underlying effects on membrane physicochemical properties, morphological structure, solute rejection behavior and hemofiltration performance. Numerous state-of-the-art characterizations on the resultant membranes showed that the hollow fiber membranes spun with the PVP having a molecular weight of 360K as the additive have the most hydrophilic, smooth and highly net negative charged inner surfaces. These membranes also exhibit the best hemofiltration performance in terms of the characteristically least fouling behavior with a normalized flux above 90%, the highest retention of serum albumin for more than 90%, and the best clearance for the simulated β2-microglobulin toxin in blood waste.