▎ 摘　　要

In this work, inspired by the bio-adhesive dopamine self-polymerization, we report a novel two-step surface polymerization strategy to produce polymer grafted graphene composite using mussel-functionalized graphene as macro ATRP initiator. First, a homogeneous bio-adhesive polydopamine layer bearing ATRP initiator was attached to graphene via a simple in situ oxidative copolymerization of dopamine (DA) and ATRP initiator-bearing DA (DA-BiBB), leading to graphene based macro-ATRP-initiator (RGO@PDA-Br). Then surface-initiated ATRP of styrene was performed from RGO@PDA-Br, resulting in the formation of polystyrene (PS) grafted graphene (RGO@PDA-PS). The resulting RGO@PDA-PS was characterized by various techniques, including FT-IR, Raman, XPS, TGA, TEM, AFM, and water contact angles (WCA), confirming the successful formation of PS layer on the surface of graphene. The amount of grafted PS can be adjusted by controlling the polymerization time and the amount of monomer fed into the system. The obtained RGO@PDA-PS showed enhanced dispersibility in common organic solvents. In addition, the grafted PS did not exhibit any delamination or exfoliation from graphene surface even after 2 h ultrasonic test, indicating good stability of RGO@PDA-PS, which could be attributed to the strong adhesion of PDA layer to graphene surface. In addition to styrene, this strategy is also workable for other vinyl monomers. Thermo-responsive and pH-responsive polymers have also been grafted onto graphene surface employing this method, indicating the generality and versatility of our strategy. Considering the facile preparation procedure and high stability of RGO@PDA-PS, this approach permits us to modify graphene with polymer via robust linkage in a convenient and nondestructive way, which combines the most advantages of non-covalent and covalent methods. (C) 2016 Elsevier B.V. All rights reserved.