Table 1 lists descriptions of the membranes. The molecular weights of the hydrophilic and hydrophobic segments in these membranes were measured using gel permeation chromatography (Tosoh Corporation, HLC-8220GPC) with polystyrene standard, TSK-GEL Super AWM-H column and TSK-GEL Super AW-H guard column.
They were measured before hydrophilic and hydrophobic segments were combined. Membrane 1 was composed of a random copolymer, and membranes 2, 3, and 4 were composed of multiblock copolymers. All the membranes had IECs of 1.4 meq/g.