Barrier Characteristics of Montmorillonite/Poly-ethylenimine Bi-layer Film via Layer-by-Layer Process

Abstract

Ultra-thin gas barrier film is required for flexible OLED displays to prevent ingress of oxygen and water vapor into the device. Recently, polymer/clay nanocomposite has been attempted for such barrier applications. In this study, barrier films consist of polyelectrolyte and montmorillonite were prepared using Layer-by-Layer self-assembly on PET substrate. In order to improve the barrier characteristics of polyelectrolyte/montmorillonite nano-film, the effects of various parameters including aspect ratio, and structure of polyelectrolyte formed on montmorillonite and thickness of the nano-films were investigated. Especially, the montmorillonite with high aspect ratio by utilizing cross filtering the montmorillonite solution was found to be effective in enhancing the barrier characteristics of the film. The results demonstrated that the ultra-thin montmorillonite/polyelectrolyte multi-layer barrier film has a potential of reducing the permeation rates suitable for flexible OLEDs.