Preparation of novel organic-inorganic nanoporous membranes

In this study, the water permeability, the rejection property of sucrose and glucose, the fouling property of humic acid as the foulant for a novel porous fluorinated polyimide membrane made by combining the ion irradiation and plasma treatment have been reported. First, an asymmetric polyimide membrane with a defect-free and thin skin layer was prepared, then ions on the skin layer were irradiated and the ion-irradiated layer was treated by plasma to form nanopores in the layer. The asymmetric polyimide membranes with a defect-free skin layer were irradiated with 50 keV He+ at 1 x 10(15) ions/cm(2), and the irradiated polyimide surfaces were treated by Ar glow discharge. The porous polyimide membrane showed a high water flux and excellent rejection properties and fouling resistance when compared with NTR-7250, which is commercially available. These findings indicated that the pore size formed on the porous polyimide membrane was effectively controlled by the plasma treatment time and the skin layer thickness. Copyright (c) 2005 John Wiley & Sons, Ltd.