A probe for moisture permeation using metal/organic composite films

Composite films made by simultaneous sublimation of metal and organic mater ials were used as sensors for moisture in overlying polymeric films, and po lymer transport properties were obtained from a spatially resolved signal. In the probe film, the molecularly dispersed metal quenched the fluorescenc e of the organic dye. Upon exposure to water vapor, the metal was oxidized and the fluorescence of the dye recovered. The intensity profile developmen t over time was modeled, and a diffusion coefficient for a ultraviolet-cura ble adhesive was obtained which compared well to other resins of its type. This technique offers several advantages in characterizing transport proper ties in confined geometries, such as those used for the passivation of ligh t-emitting diodes or other electronic devices. (C) 1999 American Institute of Physics. [S0021-8979(99)07607-0].