Polyvinyl alcohol fiber with enhanced strength and modulus and intense cyan fluorescence based on covalently functionalized graphene quantum dots

In this study, we proposed a novel and efficient way to strengthen polyvinyl alcohol (PVA) fiber using graphene quantum dots (GQDs). PVA molecular chains were grafted onto the surface of GQDs through Friedel-Crafts alkylation reaction to obtain functionalized GQDs (f-GQDs), and PVA/f-GQDs composite fiber was successfully prepared by wet spinning and post-treatment. The tensile strength and Young's modulus of the composite fiber reached up to 1229.24 MPa and 35.36 GPa which were approximately twice and 4 times those of the pure PVA fiber, respectively. Moreover, the composite fiber was demonstrated excellent resistance to solvents. In addition, the PVA/f-GQDs composite fiber showed intense and uniform cyan fluorescence, meanwhile, it could maintain stable solid-state fluorescence in acid and alkali solutions and particularly after long-term immersion in water (1 month). This study proposes a promising route for obtaining high-performance conventional fibers with some new functions.