Preparation of Thin-Layer Graphene Using RAFT Polymerization and a Thiol-Ene Click Reaction

In this paper, functionalization of graphene is conducted through click reactions for its effective dispersion. The poly(sodium 4-styrenesolfonate) (PSS) was synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. The chain end dithioester group of RAFT-polymerized PSS was reduced to a thiol and used to couple PSS to graphene oxide (GO) via a thiol-ene click reaction. An aqueous dispersion of reduced GO with PSS (PSS-rGO) resisted sedimentation due to steric effects and charge-charge repulsion between the PSS attached to rGO. Atomic force microscopy showed that the PSS-rGO mixture was composed of dispersed particles of thin-layer (1.5 nm thick) graphene. Thickness of the PSS-rGO was close to that of GO. This indicates that there was no significant re-aggregation during GO reducing process.