Particle-beam treatment of organosilicon gas separation membranes: A novel way of controlling their mass transport properties

Fast atom bombardment applied in the low keV energy range to organosilicon gas separation membranes was found to modify their mass transport properties in a controllable manner. In particular, asymmetric polyvinyltrimethylsilane membranes and polydimethylsiloxane-based composite ones were treated by particle beams obtained from various gases like Ar, He, H-2, and NH3, with particle energies of about 1 keV and doses of about 10(15) particles cm(-2). In each case, improvements in the component selectivities for various gas mixtures coupled with decreases in the component permeances were obtained. The extent of modification of the mass transport properties increased with increase of the calculated average depth of penetration of the bombarding particles. The modification of the mass transport properties was considered to take place as a result of compaction of the surface layer due to reactions like crosslinking and loss of pendant groups. (C) 1996 John Wiley & Sons, Inc.