Enhancement of Thermal and Gas Barrier Properties of Graphene-Based Nanocomposite Films

Poly(vinyl alcohol) (PVA), a naturally occurring and rapidly decomposing polymer, has gained significant attention in recent studies for its potential use in pollution preventive materials. Its cost-effectiveness and ease of availability as well as simple processing make it a suitable material for various applications. However, the only concern about PVA's applicability to various applications is its hydrophilic nature. To address this limitation, PVA-based nanocomposites can be created by incorporating inorganic fillers such as graphene (G). Graphene is a two-dimensional carbon crystal with a single atom-layer structure and has become a popular choice as a nanomaterial due to its outstanding properties. In this study, we present a simple and environmentally friendly solution processing technique to fabricate PVA and graphene-based nanocomposite films. The resulting composite films showed noticeable improvement in barrier properties against moisture, oxygen, heat, and mechanical failures. The improvement of the characteristic properties is attributed to the uniform dispersion of graphene in the PVA matrix as shown in the SEM image. The addition of graphene leads to a decrease in water vapor transmission rate (WVTR) by 79% and around 90% for the oxygen transmission rate (OTR) as compared to pristine PVA films. Notably, incorporating just 0.5 vol % of graphene results in an OTR value of as low as 0.7 cm m^-2 day^-1 bar^-1, making it highly suitable packaging applications. The films also exhibit remarkable flexibility and retained almost the same WVTR values even after going through tough bending cycles of more than 2000 at a bending radius of 2.5 cm. Overall, PVA/G nanocomposite films offer promising potential for PVA/G composite films for various attractive pollution prevention (such as corrosion resistant coatings) and packaging applications.