Patent ID: 7458251

Claim:
A method to determine a permeability of a film towards a solvent, the method comprising: providing a substrate, a container layer, and a film, wherein the container layer is situated between the substrate and the film; transferring the substrate, the container layer, and the film into a pressurizable chamber; thereafter decreasing a pressure in the pressurizable chamber; thereafter filling the pressurizable chamber with a gaseous solvent; thereafter gradually increasing the pressure in the pressurizable chamber up to a vapor pressure of the solvent, such that the solvent penetrates the film and absorbs into the container layer; determining a first value of a parameter indicative of an amount of solvent absorbed in the container layer; thereafter decreasing the pressure in the pressurizable chamber such that a second amount of the solvent absorbed in the container layer diffuses back through the film; determining a second value of the parameter indicative of the amount of solvent absorbed in the container layer; and thereafter determining the amount of solvent that diffused back through the film from the first value and the second value, wherein the amount of solvent diffused back through the film is indicative of a permeability of the film towards the solvent.