Exploiting a branched radical polymerization strategy to enhance the degree of grafting onto graphene oxide

Abstract

The synthesis of polymer-grafted graphene oxide (GO) using a branched radical polymerization strategy is described. A methacrylate-based macromonomer is used as a chain-transfer agent to enhance the degree of grafting and prevent macroscopic gel formation. A methacrylic acid-based macromonomer was first synthesized via aqueous solution catalytic chain transfer polymerization. The resultant macromonomer was used as a chain transfer agent in the radical polymerization of poly(ethylene glycol) methacrylate (PEGMA) in the presence of a dispersion of GO in a water/DMF mixture (50 : 50 w/w). The degree of grafting was determined using thermogravimetric analyses and infrared spectroscopy, and the geometrical evolution was investigated using atomic force microscopy. The grafting efficiency increased with the degree of branching.