TiO2/EVOH based reactive interlayer in Surlyn for organic device encapsulation

Barrier materials are important for improving the stability and lifetimes of organic electronic devices. A simple technique for improving the barrier properties of polymer films was considered in this work by using TiO2 nanoparticles in the interlayer to be incorporated in the polymer film. TiO2 was synthesized by the solution combustion technique, was further functionalized using stearic acid or octadecylamine to induce hydrophobicity and enhance processing of the composite interlayer. The grafting of these compounds on to TiO2 was investigated using Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis and thermo-gravimetric analysis. The functionalized and neat TiO2 were blended with poly (vinyl alcohol-ethylene) (EVOH) and were melt compressed between Surlyn films. The resulting nanocomposite films were tested for their transparency and barrier properties using UV-visible spectroscopy and calcium degradation test, respectively. Further, the effectiveness of these barrier films in encapsulating organic devices was determined from accelerated aging tests. Therefore, the synthesized barrier films with neat and functionalized TiO2 in the interlayers proved to be effective as moisture barrier composite films.