Preparation of asymmetric hollow-fiber membrane with ultrathin dense skin layer on the outer surface using dry/wet phase inversion process

Abstract

The authors have developed an asymmetric hollow-fiber membrane with a skin layer on the outer surface using a dry/wet phase inversion process with a newly synthesized aromatic fluorinated polyamide. Because the skin layer is ultrathin and has no defects, the membrane has gas selectivity in addition to higher gas flux. The membrane has excellent hemocompatibility, which is probably related to packing density of the skin layer. Authors are now clarifying the mechanism of the microstructure formation of the membrane relating to spinning conditions by the standing point of polymer physics. Generally, the microstructure of a polymeric membrane prepared by a phase inversion process is discussed using the phase diagram of the system. However, the process is so dynamic that conventional discussion based on the start and end points is not sufficient, but which path is to be chosen on the phase diagram is more important.