Interaction of Permeates during the Measurement of Permeation Coefficients of Dense Polymer Films under Realistic Conditions

The knowledge of the material properties is a key-aspect to the engineering of reliable products. Such a material property, the permeability towards water and oxygen, is not only of importance for packaging but also for the microelectronic and solar industry. For standard applications with low requirements permeation rates of single permeates can be measured with commercially available instruments. In this publication simultaneous measurements of several permeates are analyzed showing the interdependence of permeation rates of three major permeates (water vapor, oxygen and nitrogen gas) depending on their concentration. Based on these results the measurements of the permeability for single permeates can only be seen as an approximation by ignoring competitive effects of different permeates as found for most application environments.