Oxidative polymerization of pyrrole on the surface of platelets of graphene oxide (GO) was demonstrated to generate polypyrrole/GO (PPy/GO) hybrid assemblies. The polymerization reactions were performed in GO acid dispersions using ammonium persulfate (APS) as an oxidant. Model kinetic reactions were carried out by H-1 NMR spectroscopy with APS at low temperatures. Evidence was found for an increase in the rate of polymerization of pyrrole in the presence of GO. IR and ESCA results indicate that the neutralization of the COOH groups on the GO may be due to interaction with the PPy. The morphology of PPy/GO assemblies analyzed by AFM revealed spherical particles of PPy agglomerated on the surface of GO platelets. Furthermore, TEM analysis indicated that polymerization of pyrrole occurred on both the surface of the GO and in between the GO layers. This type of synthesis could offer an approach to the generation of new solid hybrids and allow systematic changes of their physical properties. (C) 2015 Elsevier Ltd. All rights reserved.