Determination of oxygen permeability of polymers using in-situ photo-generated heptacene

Heptacene generated in-situ in a polymer matrix using a photochemical route undergoes oxidation with diffused oxygen leading to the formation of endoperoxides. We have found the high reactivity of heptacene, a linear poly(acene), toward molecular oxygen can be used to determine oxygen permeability of polymer films. The rate of disappearance of heptacene, due to oxidation, was found to be directly related to the oxygen permeability of the polymer. A simple spectroscopic method to estimate oxygen permeability of polymer films by monitoring the visible/near infra-red absorption of heptacene is described.