The time lag for the diffusion of gas mixtures

Abstract

The diffusion of a gas mixture of several components through a polymer membrane is considered. An expression is obtained for the time lag L assuming that the component flows are non-interacting and that the component diffusion and solubility coefficients are not functions of concentration. Measurements were made with a krypton-neon mixture and a silicone rubber membrane and good agreement obtained with the theoretical expressions. To establish the steady state of flow in a single component system requires a time of ∼3L. For mixture diffusion it is shown that this criterion is not usually valid.