The development of low cost, easy processable, barrier encapsulant materials is of critical importance for the rapid commercialization of organic/electronic devices. In this study, flexible and thermally stable composites were prepared by simple solution processing using polyvinyl alcohol as the base polymer matrix and reactive zinc oxide nanoparticles as the dispersed phase. These materials were characterized for their applications as barrier materials for moisture and oxygen sensitive organic devices. Various studies such as thermal analysis, mechanical analysis, surface analysis and permeability studies were used to characterize the composite films for their possible use as a passivation material. The material was used to encapsulate Schottky structured devices, and the performance of these encapsulated devices under accelerated weathering was studied. © 2012 The Royal Society of Chemistry.