Polystyrene-grafted graphene with improved solubility in organic solvents and its compatibility with polymers

A simple “grafting to” method is developed to covalently functionalize chemically modified graphene with a polystyrene-based graft copolymer, polystyrene-g-(glycidyl methacrylate-co-styrene) (PS-g-(GMA-co-St)). PS-grafted graphene (PS-g-graphene for short), with a PS grafting degree of ∼60 wt%, is soluble in a wide variety of organic solvents. A freestanding, highly flexible film of PS-g-graphene is obtained by vacuum filtration of a PS-g-graphene/chloroform solution with a polytetrafluoroethylene membrane, and its electrical conductivity is measured to be ∼170 S m−1. The film itself is a mechanically strong, electrically conductive graphene/PS composite film. PS-g-graphene can be incorporated in the PS-based copolymer matrices with high compatibility, yielding a new class of graphene/polymer composites.