Effect of heavy-ion irradiation on the gas permeability of poly(ethylene terephthalate) (PET) membranes

A poly(ethylene terephthalate) (PET) membrane was used to study the effect of heavy-ion irradiation on gas permeability and selectivity. In an ambient temperature range of 303-333 K, permeability coefficients for He, N-2, O-2 , and CO2 were determined with the vacuum-pressure and time-lag methods. Ga s-permeability coefficients of the membranes, which were irradiated with so me specific heavy ions, increased remarkably without a significant change i n the polymer structure by ion irradiation. The permeation rates of these m embranes were inversely proportional to the square root of the molecular we ight of the gasses and showed Knudsen flow because of the formation of pore s caused by heavy-ion irradiation. (C) 2001 John Wiley & Sons, Inc.