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.