A method for measuring oxygen diffusion and oxygen permeation in polymer films based on fluorescence quenching

摘要

We describe a new and simple technique based on luminescence quenching for measuring oxygen diffusion and oxygen permeation in free-standing polymer films and in viscous liquid polymers. The polymer film acts as a membrane to separate the source of oxygen from a small receiving volume containing an oxygen sensor. The sensor is made of a resin containing a phosphorescent dye sensitive to oxygen quenching. The measured film is either laminated on the sensor (film-sensor) or separated from it with a spacer (film-spacer-sensor). At time t = 0, the film equilibrated in atmospheric air is hushed with pure oxygen and the time profile of the decay of the phosphorescence emission from the sensor is monitored. The Stern-Volmer equation for luminescence quenching is combined with Fick's law for diffusion to derive the mathematical expressions describing each of our experiments. By means of this method, we measured the diffusion coefficient and permeability with a good accuracy in various free-standing polymers films such as polystyrene and poly(ethylene terephthalate). We also measure the oxygen diffusion coefficient in un-cross-linked polyisobutylene as an example of a viscous liquid polymer. [References: 21]