To evaluate gas permeation properties of foam membranes, a preliminary investigation of the permeation of O2, N2, and CO2 through a monolayer of foam bubbles formed on an aqueous glycerol solution with saponin as surfactant was carried out in a new static foam membrane test cell. Foam stability, a prerequisite to meaningful measurement, was highest with a 70% glycerol solution. Using the notion of an average foam bubble, time-dependent measurements of gas composition above foam bubbles and foam bubble height reduction yielded values of permeation parameters from the solution of appropriate mass balance equations. The O2 permeation parameter defined by the ratio of the O2 permeability coefficient and the foam bubble wall thickness was found to have a value comparable to that of a 1-mil-thick silicone rubber film. The O2N2 separation factor, found to be around 2 for the same system, is comparable also to that of a silicone rubber film. Significant absorption of CO2 in the surfactant liquid solution suggests limitations of this new foam permeation cell to gases with extremely limited solubility.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Colloid and Surface Chemistry