Permeation rates of low molecular weight gases through a plasma synthesized allyl alcohol membrane

Gas separation membranes were produced from the pulsed plasma deposition of poly(allyl alcohol). It was discovered that only low duty cycle, pulsed plasma deposition (1 ms on/30 ms off, 300 W peak power) produced membranes of sufficient uniformity to permit permeation studies. The membranes, deposited on porous ceramic filters, were found to permeate common gases through a combination of porous flow and the flow of adsorbed gases on the inner surface of the pores. The degree of surface transport was correlated with the critical temperature of the gas under test. The amount of surface transport for all gases tested increased strongly with applied pressure. The poly(allyl alcohol) films were compared with published data for porous cellulose acetate membranes; it was found that the poly(allyl alcohol) membranes had greatly enhanced surface transport compared to the cellulose acetate membranes.