Low temperature plasma treatment of asymmetric polysulfone membranes for permanent hydrophilic surface modification

A plasma treatment that renders asymmetric polysulfone membranes permanentl y hydrophilic is reported. Our modification strategy entails treating these membranes downstream from an inductively coupled rf plasma source. Contact angle measurements confirm that the membranes are completely wettable with water as a result of H2O plasma treatment. Mon importantly, the. hydrophil ic modification is permanent as plasma-treated membranes remain wettable fo r more than 16 months after plasma treatment. This treatment achieves the d esired change in wettability for microporous as well as ultrafiltration pol ysulfone membranes, illustrating the universality of this method. XPS analy sis of treated membranes demonstrates this dramatic change in wettability i s a result of chemical changes in the membrane induced by plasma treatment. Moreover, the membrane modification is complete as the plasma penetrates t he thickness of the membrane, thereby modifying the entire membrane cross-s ection. (C) 2001 Elsevier Science B.V. All rights reserved.