High Performance of PVA Nanocomposite Reinforced by Janus-like Asymmetrically Oxidized Graphene: Synergetic Effect of H-bonding Interaction and Interfacial Crystallization

Macromolecule nanocrystal network and strong interfacial interaction are always beneficial to enhance the mechanical property of polymer-based nanocomposites. Poly(vinyl alcohol) (PVA), a typical biocompatible semicrystalline polymer, is an ideal candidate for preparing high performance polymer-based nanocomposites. However, the rich hydrogen bonds between PVA matrix and graphene oxide (GO) can disrupt the formation of PVA nanocrystal network. Thus, it remains a great challenge to achieve both strong and tough PVA-GO nanocomposites. Herein, by introducing a novel Janus-like amphiphilic graphene oxide (JGO), both hydrogen bonding and interfacial crystallization have been constructed between JGO sheets and PVA matrix. Benefiting from amphiphilic interfacial interaction and the enhanced crystal network, both PVA-JGO dried films and their swollen hydrogel films show superior mechanical properties than those of traditional PVA-GO nanocomposites. PVA-JGO dried films exhibit a 264% improvement of toughness at a JGO loading of 1 wt%. Meanwhile, the corresponding PVA-JGO swollen hydrogel films display simultaneous improvement of nearly 8 times increase of tensile strength and 20 times increase of toughness compared to traditional PVA-GO nanocomposite. This work indicates multiple interfacial interactions and macromolecule crystal networks can be concurrent in PVA nanocomposites by innovative modification of nanofillers, providing a new strategy to construct PVA nanocomposites with high strength and high toughness. The integration of outstanding mechanical and swelling resistance properties on PVA-JGO nanocomposite films render their promising applications, such as packaging and toughening hydrogel materials.