High-performance, multi-functional and well-dispersed graphene/epoxy nanocomposites via internal antiplasticization and π-πF interactions

It is a longstanding challenge for epoxy-based nanocomposites to optimize the dispersity of graphene so as to improve the mechanical properties and endow more functions. Non-covalent functionalization of graphene via dispersants is a crucial strategy to achieve well-dispersion, which can maintain the original physical/chemical properties. However, the reported dispersants significantly reduce mechanical properties of matrix and their stable graphene concentration is limited. Herein, 2,3,5,6-tetrafluorobenzyloxyglycidyl ether (TFGE) is synthesized and used as a dispersant to realize non-covalent functionalization of graphene, which can further improve the interface, dispersity and loading of graphene via π-πF interactions between tetrafluorophenyl and graphene, compared with π-π interactions. Moreover, TFGE can simultaneously reinforce and toughen the matrix via internal antiplasticization. The well-designed epoxy-based nanocomposite with ultralow graphene loading (less than 0.03 wt%) shows outstanding mechanical and thermomechanical properties, photo/thermochromic ability, light absorption, flame resistance as well as adhesive strength. This facile strategy provides an efficient guideline for better design and large-scale preparation of high-performance and multi-functional graphene/epoxy nanocomposites applied in adhesive, coating, anti-fake and structural materials.