A facile graft from method to prepare molecular-level dispersed graphene-polymer composites

Graphenepolymer composites of positive-charged poly(dimethyl aminoethyl acrylate), negative-charged poly(acrylic acid), and neutral polystyrene were prepared by graft from methodology using reversible addition fragmentation chain transfer (RAFT) polymerization via a pyrene functional RAFT agent (PFRA) modified graphene precursor. Fluorescence spectroscopy and attenuated total reflection infrared (ATR-IR) evidenced that the PFRA was attached on the graphene basal planes by pp stacking interactions, which is strong enough to anti-dissociation in the polymerization mixture up to 80 degrees C. Atomic force microscopy (AFM) revealed that the thickness of a graphenepolymer sheet was about 4.0 nm. Graphene composites of different polymers with the same polymerization degree exhibited similar conductivity; however, when the polymer chain was designed as random copolymer the conductivity was significantly decreased. It was also observed that the longer the grafted polymer chains the lower the conductivity. ATR-IR spectroscopy and thermogravimetric analysis were also performed to characterize the as-prepared composites. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012